M3: Go API per UI contract, embedded UI, openapi compat check, nmon-devtools, live gate + screenshots; M4 WP1 reachability and dependency suppression

Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_01Lx9FNLG2CqeBbVGGd9bFsP

.github/workflows/ci.yml

@@ -1,6 +1,17 @@
 name: ci
 on: [push, pull_request]
 jobs:
+  lint:
+    # Hard rule (docs/MAINTAINABILITY.md): any finding fails the build.
+    runs-on: ubuntu-latest
+    steps:
+      - uses: actions/checkout@v4
+      - uses: actions/setup-go@v5
+        with: { go-version: stable }
+      - uses: actions/setup-node@v4
+        with: { node-version: 22 }
+      - run: cd web && npm ci
+      - run: make lint
   test:
     strategy:
       matrix:

.gitignore

@@ -1,5 +1,6 @@
 /nmon
 /nmon-arm64
+/nmon-devtools
 /internal/vmsup/bin/*.tar.gz
 /internal/vmsup/bin/victoria-metrics-*
 web/node_modules/
@@ -8,3 +9,5 @@ web/dist/
 *.test
 coverage.out
 /nmon-librenms-import
+/internal/webui/dist/*
+!/internal/webui/dist/.gitkeep

.golangci.yml

@@ -0,0 +1,153 @@
+# Enforces docs/MAINTAINABILITY.md. A hard rule: `make lint` must be clean for any gate to pass.
+version: "2"
+
+run:
+  timeout: 10m
+  tests: true
+
+# Report every finding: funlen and gocognit flag the same line and must both show.
+issues:
+  max-issues-per-linter: 0
+  max-same-issues: 0
+  uniq-by-line: false
+
+linters:
+  default: none
+  enable:
+    - govet
+    - errcheck
+    - staticcheck
+    - unused
+    - ineffassign
+    - funlen
+    - cyclop
+    - gocognit
+    - nestif
+    - dupl
+    - lll
+    - errorlint
+    - usestdlibvars
+    - misspell
+    - revive
+    - depguard
+    - forbidigo
+    - nolintlint
+    - unconvert
+    - bodyclose
+    - copyloopvar
+
+  settings:
+    funlen:
+      lines: 80
+      statements: 50
+      ignore-comments: true
+    cyclop:
+      max-complexity: 15
+    gocognit:
+      min-complexity: 20
+    nestif:
+      min-complexity: 4
+    dupl:
+      threshold: 150
+    lll:
+      line-length: 140
+    misspell:
+      # MikroTik's OS name and a profile name, not a typo of "routers".
+      ignore-rules: [routeros]
+    nolintlint:
+      require-explanation: true
+      require-specific: true
+    revive:
+      rules:
+        - name: exported
+          arguments: ["disableStutteringCheck"]
+        - name: package-comments
+        - name: var-naming
+        - name: indent-error-flow
+        - name: error-strings
+        - name: receiver-naming
+        - name: unexported-return
+    forbidigo:
+      analyze-types: true
+      forbid:
+        - pattern: '^time\.(Now|Sleep|After|Tick|NewTicker|NewTimer)$'
+          msg: "use internal/clock so tests control time (docs/MAINTAINABILITY.md)"
+    depguard:
+      rules:
+        orm-only-in-store:
+          files: ["$all", "!**/internal/store/**"]
+          deny:
+            - pkg: github.com/uptrace/bun
+              desc: SQL and the ORM live only in internal/store
+            - pkg: database/sql
+              desc: SQL lives only in internal/store
+        app-only-from-cmd:
+          files: ["$all", "!**/cmd/**"]
+          deny:
+            - pkg: github.com/v10networks/nmon/internal/app
+              desc: only cmd/* wires the application
+        api-only-from-app:
+          files: ["$all", "!**/internal/app/**", "!**/internal/api/**", "!$test"]
+          deny:
+            - pkg: github.com/v10networks/nmon/internal/api
+              desc: only internal/app mounts the API
+        collection-paths-independent:
+          files:
+            - "**/internal/poller/**"
+            - "**/internal/discovery/**"
+            - "**/internal/traps/**"
+            - "**/internal/ingest/**"
+            - "**/internal/checks/**"
+            - "**/internal/rollup/**"
+            - "**/internal/alert/**"
+          deny:
+            - pkg: github.com/v10networks/nmon/internal/poller
+              desc: collection paths share code via a lower package, not each other
+            - pkg: github.com/v10networks/nmon/internal/discovery
+              desc: collection paths share code via a lower package, not each other
+            - pkg: github.com/v10networks/nmon/internal/traps
+              desc: collection paths share code via a lower package, not each other
+        devtools-not-in-nmon:
+          # profile_record.go (`nmon profile record`, M2) already uses the recording types and writer; nothing else may.
+          files: ["**/cmd/nmon/**", "!**/cmd/nmon/profile_record.go", "!$test"]
+          deny:
+            - pkg: github.com/v10networks/nmon/internal/simagent
+              desc: the simulator belongs to cmd/nmon-devtools and tests, never the shipped binary
+            - pkg: github.com/v10networks/nmon/internal/fixturegen
+              desc: the fixture generator belongs to cmd/nmon-devtools and tests, never the shipped binary
+        devtools-no-core:
+          files: ["**/cmd/nmon-devtools/**"]
+          deny:
+            - pkg: github.com/v10networks/nmon/internal/app
+              desc: nmon-devtools talks to a running nmon over HTTP
+            - pkg: github.com/v10networks/nmon/internal/api
+              desc: nmon-devtools talks to a running nmon over HTTP
+        importer-not-in-nmon:
+          files: ["**/cmd/nmon/**"]
+          deny:
+            - pkg: github.com/v10networks/nmon/internal/librenms
+              desc: the LibreNMS importer is a separate tool (DEVIATIONS 9)
+
+  exclusions:
+    paths:
+      - web/node_modules
+    rules:
+      # Table-driven tests are long by nature; every other linter still applies.
+      - path: _test\.go
+        linters: [funlen, cyclop, gocognit, nestif, dupl, lll, forbidigo]
+      # The clock package wraps time; cmd/ and the test-only simulator may use real time.
+      - path: internal/clock/
+        linters: [forbidigo]
+      - path: cmd/
+        linters: [forbidigo]
+      # A package is allowed to import itself's own test helpers and itself.
+      - path: internal/(poller|discovery|traps)/.*_test\.go
+        linters: [depguard]
+
+formatters:
+  enable:
+    - gofmt
+    - goimports
+  exclusions:
+    paths:
+      - web/node_modules

Makefile

@@ -1,24 +1,33 @@
 GO        ?= go
 TAGS      ?= vmembed
-LDFLAGS   := -s -w
+VERSION   ?= $(shell git describe --tags --always --dirty 2>/dev/null || echo dev)
+BUILD     ?= $(shell git rev-parse --short HEAD 2>/dev/null || echo unknown)-$(shell date -u +%Y%m%d)
+LDFLAGS   := -s -w -X github.com/v10networks/nmon/internal/buildinfo.Version=$(VERSION) -X github.com/v10networks/nmon/internal/buildinfo.Build=$(BUILD)
 BIN       := nmon
 PG_DSN    ?= postgres://nmon:nmon@localhost:55432/nmon?sslmode=disable
 
-.PHONY: all build importer build-arm64 build-noembed fetch-vm web test test-integration test-pg test-v6only vet gate-m1 gate-m2 gate-m3 gate-m4 gate-m5 gate-m6 clean
+.PHONY: devtools all lint lint-go lint-web build importer build-arm64 build-noembed fetch-vm web test test-integration test-pg test-v6only vet gate-m1 gate-m2 gate-m3 gate-m4 gate-m5 gate-m6 clean
 
 all: build
 
 fetch-vm:
 	./scripts/fetch-vm.sh
 
-# The UI is built first when web/ exists so embed.FS picks it up.
+# The UI is built first, then copied into internal/webui/dist for go:embed (git-ignored).
 web:
-	@if [ -f web/package.json ]; then cd web && npm ci --no-audit --no-fund && npm run build; fi
+	@if [ -f web/package.json ]; then \
+		cd web && { [ -d node_modules ] || npm ci --no-audit --no-fund; } && npm run build && \
+		cd .. && rm -rf internal/webui/dist/* && cp -r web/dist/. internal/webui/dist/ && touch internal/webui/dist/.gitkeep; \
+	fi
 
-build: fetch-vm
+build: fetch-vm web
 	CGO_ENABLED=0 $(GO) build -tags '$(TAGS)' -ldflags '$(LDFLAGS)' -o $(BIN) ./cmd/nmon
 
-build-arm64: fetch-vm
+# Developer tools (backfill, seed-demo) are a separate binary that is never shipped.
+devtools:
+	CGO_ENABLED=0 $(GO) build -o nmon-devtools ./cmd/nmon-devtools
+
+build-arm64: fetch-vm web
 	CGO_ENABLED=0 GOOS=linux GOARCH=arm64 $(GO) build -tags '$(TAGS)' -ldflags '$(LDFLAGS)' -o $(BIN)-arm64 ./cmd/nmon
 
 importer:
@@ -27,6 +36,18 @@ importer:
 build-noembed:
 	CGO_ENABLED=0 $(GO) build -ldflags '$(LDFLAGS)' -o $(BIN) ./cmd/nmon
 
+GOLANGCI := go run github.com/golangci/golangci-lint/v2/cmd/golangci-lint@v2.14.0
+
+# Hard rule (docs/MAINTAINABILITY.md): every gate runs this first and it must be clean.
+lint: lint-go lint-web
+
+lint-go:
+	$(GOLANGCI) run ./...
+	./scripts/lint-filesize.sh
+
+lint-web:
+	@if [ -f web/package.json ]; then cd web && npm run lint; fi
+
 vet:
 	$(GO) vet ./...
 
@@ -47,4 +68,4 @@ gate-m1 gate-m2 gate-m3 gate-m4 gate-m5 gate-m6: gate-m%:
 	./scripts/gate-m$*.sh
 
 clean:
-	rm -f $(BIN) $(BIN)-arm64 nmon-librenms-import
+	rm -f $(BIN) $(BIN)-arm64 nmon-devtools nmon-librenms-import

cmd/nmon-devtools/backfill.go

@@ -0,0 +1,162 @@
+package main
+
+import (
+	"bytes"
+	"context"
+	"errors"
+	"fmt"
+	"math"
+	"net/http"
+	"net/url"
+	"strings"
+	"time"
+
+	"github.com/v10networks/nmon/internal/metrics"
+)
+
+// backfillConfig is what one `devtools backfill` run writes, for every interface in ifaces.
+type backfillConfig struct {
+	hotURL  string
+	device  string
+	ifaces  []string
+	days    int
+	step    time.Duration
+	pattern string
+	meanBps float64 // bits/s; 0 derives the mean from the live rate, else a stable per-interface value
+	seed    uint64
+	hc      *http.Client
+	logf    func(format string, a ...any)
+}
+
+func backfillCmd(ctx context.Context, args []string) error {
+	cfg := backfillConfig{hc: &http.Client{Timeout: 2 * time.Minute}, logf: func(f string, a ...any) { fmt.Printf(f+"\n", a...) }}
+	fs := devFlagSet("backfill")
+	var ifaces stringList
+	var mbps float64
+	fs.StringVar(&cfg.hotURL, "hot-url", "", "base URL of the hot VictoriaMetrics (required; see \"metric stores up\" in the serve log)")
+	fs.StringVar(&cfg.device, "device", "", "device slug (the series' device label)")
+	fs.Var(&ifaces, "iface", "interface ULID; repeat the flag or separate with commas")
+	fs.IntVar(&cfg.days, "days", 31, "days of history to write, ending where the live data begins")
+	fs.DurationVar(&cfg.step, "step", 60*time.Second, "sample spacing")
+	fs.StringVar(&cfg.pattern, "pattern", patternDiurnal, "traffic shape: diurnal or flat")
+	fs.Float64Var(&mbps, "mean-mbps", 0, "mean rate in Mbit/s; 0 follows the live rate when there is one")
+	fs.Uint64Var(&cfg.seed, "seed", 1, "noise seed")
+	if err := fs.Parse(args); err != nil {
+		return flagErr(err)
+	}
+	cfg.ifaces, cfg.meanBps = ifaces, mbps*1e6
+	if err := cfg.validate(); err != nil {
+		return err
+	}
+	for _, id := range cfg.ifaces {
+		if err := cfg.backfillIface(ctx, id); err != nil {
+			return fmt.Errorf("iface %s: %w", id, err)
+		}
+	}
+	return nil
+}
+
+func (c *backfillConfig) validate() error {
+	switch {
+	case c.hotURL == "":
+		return errors.New("--hot-url is required")
+	case c.device == "" || len(c.ifaces) == 0:
+		return errors.New("--device and at least one --iface are required")
+	case c.days < 1 || c.step < time.Second:
+		return errors.New("--days must be at least 1 and --step at least 1s")
+	case c.pattern != patternDiurnal && c.pattern != patternFlat:
+		return fmt.Errorf("unknown --pattern %q (diurnal or flat)", c.pattern)
+	}
+	c.hotURL = strings.TrimRight(c.hotURL, "/")
+	return nil
+}
+
+// liveSeries is what the hot store already holds for one series: the first
+// sample (where history must end and which value it must join) and the live rate.
+type liveSeries struct {
+	ts   time.Time
+	val  float64
+	rate float64 // units per second between the first two samples; 0 when unknown
+	ok   bool
+}
+
+// backfillIface writes in/out octet counters and the oper status for one interface.
+func (c *backfillConfig) backfillIface(ctx context.Context, iface string) error {
+	n := c.days * int(24*time.Hour/c.step)
+	var samples []metrics.Sample
+	var end time.Time
+	for d, dir := range []struct {
+		metric string
+		salt   uint64
+	}{{"ifHCInOctets", 0x1111}, {"ifHCOutOctets", 0x2222}} {
+		live, err := c.probe(ctx, dir.metric, iface)
+		if err != nil {
+			return err
+		}
+		if d == 0 {
+			end = c.endTime(live)
+		}
+		samples = append(samples, c.counter(dir.metric, iface, end, n, live, c.seed^dir.salt)...)
+	}
+	status := 1.0
+	if live, err := c.probe(ctx, "ifOperStatus", iface); err == nil && live.ok {
+		status = live.val
+	}
+	for i := 0; i < n; i++ {
+		ts := end.Add(-time.Duration(n-1-i) * c.step)
+		samples = append(samples, metrics.New("ifOperStatus", status, ts, metrics.LabelDevice, c.device, metrics.LabelIface, iface))
+	}
+	if err := c.send(ctx, samples); err != nil {
+		return err
+	}
+	c.logf("backfilled %s/%s: %d days at %s (%d samples)", c.device, iface, c.days, c.step, len(samples))
+	return nil
+}
+
+// endTime is one step before the first live sample, or one step ago when there is none.
+func (c *backfillConfig) endTime(live liveSeries) time.Time {
+	if live.ok {
+		return live.ts.Add(-c.step).Truncate(time.Millisecond)
+	}
+	return time.Now().Add(-c.step).Truncate(time.Millisecond)
+}
+
+// counter builds one direction's history ending at end. When the live counter
+// is known and large enough, the history is shifted so its last value is where
+// the live counter was one step earlier and the join shows no reset.
+func (c *backfillConfig) counter(metric, iface string, end time.Time, n int, live liveSeries, salt uint64) []metrics.Sample {
+	mean := c.meanBps / 8
+	if mean == 0 && live.rate > 0 {
+		mean = live.rate
+	}
+	if mean == 0 {
+		mean = defaultMeanBytesPerSec(iface, salt)
+	}
+	start := end.Add(-time.Duration(n-1) * c.step)
+	vals := counterSeries(c.pattern, start, n, c.step, mean, salt)
+	var offset float64
+	if live.ok {
+		offset = live.val - mean*c.step.Seconds() - vals[n-1]
+		if offset < 0 {
+			c.logf("warning: %s %s: live counter %.3g is below the %.3g bytes of history; the join will look like a counter reset",
+				c.device, metric, live.val, vals[n-1])
+			offset = 0
+		}
+	}
+	out := make([]metrics.Sample, n)
+	for i, v := range vals {
+		ts := start.Add(time.Duration(i) * c.step)
+		out[i] = metrics.New(metric, math.Floor(v+offset), ts, metrics.LabelDevice, c.device, metrics.LabelIface, iface)
+	}
+	return out
+}
+
+// probe reads the earliest samples of metric{iface=...} from the hot store.
+func (c *backfillConfig) probe(ctx context.Context, metric, iface string) (liveSeries, error) {
+	q := url.Values{"match[]": {fmt.Sprintf(`%s{iface=%q}`, metric, iface)}}
+	var raw bytes.Buffer
+	if err := c.get(ctx, c.hotURL+"/api/v1/export?"+q.Encode(), &raw); err != nil {
+		return liveSeries{}, err
+	}
+	return parseExport(raw.Bytes())
+}

cmd/nmon-devtools/fleet.go

@@ -0,0 +1,130 @@
+package main
+
+import (
+	"fmt"
+	"strconv"
+	"strings"
+
+	"github.com/gosnmp/gosnmp"
+
+	"github.com/v10networks/nmon/internal/fixturegen"
+	"github.com/v10networks/nmon/internal/profile"
+	"github.com/v10networks/nmon/internal/simagent"
+)
+
+// demoDevice is one simulated device of `devtools seed-demo`.
+type demoDevice struct {
+	name, site, role string
+	kind             string // counters, big, router, ups, v1, down: what the gate and screenshots look for
+	rec              *simagent.Recording
+	community        string
+	version          string // v2c unless set
+	hc               bool   // 64-bit counters, so history can be back-filled
+}
+
+// counterBase is added to every simulated 64-bit octet counter so that the
+// back-filled history (about 3e13 bytes for 31 days at 100 Mbit/s) fits below
+// the live counter and the join shows no reset.
+const counterBase = 100_000_000_000_000
+
+const (
+	oidHCIn  = "1.3.6.1.2.1.31.1.1.1.6."
+	oidHCOut = "1.3.6.1.2.1.31.1.1.1.10."
+	oidUp    = "1.3.6.1.2.1.1.3.0"
+)
+
+// animate returns a copy of rec whose 64-bit octet counters advance at a steady
+// per-port rate from counterBase and whose uptime ticks, so successive polls see
+// traffic. Counters that already advance keep their rate and only gain the base.
+func animate(rec *simagent.Recording) *simagent.Recording {
+	recs := append([]simagent.Record(nil), rec.Records()...)
+	for i := range recs {
+		r := &recs[i]
+		switch {
+		case r.Type == gosnmp.Counter64 && (strings.HasPrefix(r.OID, oidHCIn) || strings.HasPrefix(r.OID, oidHCOut)):
+			recs[i] = animateCounter(*r)
+		case r.OID == oidUp && r.Dyn == nil:
+			if v, ok := r.Value.(uint32); ok {
+				r.Dyn, r.Value = &simagent.Dynamic{Rate: 100, Initial: uint64(v)}, nil
+			}
+		}
+	}
+	return simagent.NewRecording(recs)
+}
+
+func animateCounter(r simagent.Record) simagent.Record {
+	if r.Dyn != nil {
+		d := *r.Dyn
+		d.Initial += counterBase
+		r.Dyn = &d
+		return r
+	}
+	k, _ := strconv.Atoi(r.OID[strings.LastIndexByte(r.OID, '.')+1:])
+	dir := 1
+	if strings.HasPrefix(r.OID, oidHCOut) {
+		dir = 2
+	}
+	mbps := 1 + (k*(31+7*dir))%90
+	r.Dyn = &simagent.Dynamic{Rate: float64(mbps) * 125_000, Initial: counterBase + uint64(k)*1_000_000_000}
+	r.Value = nil
+	return r
+}
+
+// profileDevice builds a device that a shipped profile matches, with traffic.
+func profileDevice(set *profile.Set, prof, name, site, role, kind string, ports int) (demoDevice, error) {
+	spec, ok := fixturegen.SpecFor(prof)
+	if !ok {
+		return demoDevice{}, fmt.Errorf("no fixture spec for profile %q", prof)
+	}
+	res, ok := set.Lookup(prof)
+	if !ok {
+		return demoDevice{}, fmt.Errorf("no profile %q", prof)
+	}
+	spec.SysName = name
+	if ports > 0 {
+		spec.Ports = ports
+	}
+	rec, err := fixturegen.FromProfile(res, spec)
+	if err != nil {
+		return demoDevice{}, fmt.Errorf("%s: %w", name, err)
+	}
+	return demoDevice{name: name, site: site, role: role, kind: kind, rec: animate(rec), community: "public", hc: true}, nil
+}
+
+// buildFleet is the small network used for live screenshots: a 48-port switch,
+// routers, a firewall, a UPS, one 32-bit device, the counters fixture and one
+// device whose agent is stopped after seeding, so it reads as down.
+func buildFleet(set *profile.Set, countersRec string) ([]demoDevice, error) {
+	counters, err := simagent.LoadRecording(countersRec)
+	if err != nil {
+		return nil, err
+	}
+	fleet := []demoDevice{{
+		name: "yyz1-edge1", site: "yyz1", role: "edge", kind: "counters", rec: animate(counters), community: "public", hc: true,
+	}}
+	for _, p := range []struct {
+		prof, name, site, role, kind string
+		ports                        int
+	}{
+		{"cisco-ios", "yyz1-acc01", "yyz1", "access", "big", 48},
+		{"cisco-ios", "yyz1-acc02", "yyz1", "access", "router", 24},
+		{"cisco-ios", "ott1-acc02", "ott1", "access", "down", 24}, // its agent is stopped once seeding is done
+		{"juniper-junos", "yyz1-core1", "yyz1", "core", "router", 0},
+		{"arista-eos", "yul1-core1", "yul1", "core", "router", 0},
+		{"mikrotik-routeros", "ott1-gw1", "ott1", "gateway", "router", 0},
+		{"fortigate", "yyz1-fw1", "yyz1", "firewall", "router", 0},
+		{"apc-ups", "yyz1-ups1", "yyz1", "power", "ups", 0},
+	} {
+		d, err := profileDevice(set, p.prof, p.name, p.site, p.role, p.kind, p.ports)
+		if err != nil {
+			return nil, err
+		}
+		fleet = append(fleet, d)
+	}
+	// 32-bit counters on 1 Gbit/s ports: the API flags them unreliable and the UI never graphs them.
+	v1 := fixturegen.Generic(fixturegen.Options{Ports: 12, SysName: "yul1-acc03", Counters: true, NamePattern: "Fa0/%d"})
+	fleet = append(fleet, demoDevice{
+		name: "yul1-acc03", site: "yul1", role: "access", kind: "v1", rec: v1, community: "nmon-v1", version: "v1",
+	})
+	return fleet, nil
+}

cmd/nmon-devtools/main.go

@@ -0,0 +1,119 @@
+// Command nmon-devtools holds developer helpers for the gates and for screenshots: backfill (synthetic
+// history into the hot store) and seed-demo (a simulated network added to a running nmon). It talks to nmon
+// only through its HTTP API and to the hot store through --hot-url, and is never shipped (docs/dev.md).
+package main
+
+import (
+	"context"
+	"encoding/json"
+	"errors"
+	"flag"
+	"fmt"
+	"io"
+	"net/http"
+	"os"
+	"os/signal"
+	"strings"
+	"syscall"
+	"time"
+)
+
+var errUsage = errors.New("usage: nmon-devtools backfill|seed-demo [flags] (see docs/dev.md)")
+
+func main() {
+	ctx, stop := signal.NotifyContext(context.Background(), os.Interrupt, syscall.SIGTERM)
+	defer stop()
+	if err := run(ctx, os.Args[1:]); err != nil {
+		fmt.Fprintln(os.Stderr, "nmon-devtools:", err)
+		os.Exit(1)
+	}
+}
+
+func run(ctx context.Context, args []string) error {
+	if len(args) == 0 {
+		return errUsage
+	}
+	switch args[0] {
+	case "backfill":
+		return backfillCmd(ctx, args[1:])
+	case "seed-demo":
+		return seedDemoCmd(ctx, args[1:])
+	default:
+		return fmt.Errorf("unknown command %q: %w", args[0], errUsage)
+	}
+}
+
+// flagErr turns flag.ErrHelp into a clean exit.
+func flagErr(err error) error {
+	if errors.Is(err, flag.ErrHelp) {
+		os.Exit(0)
+	}
+	return err
+}
+
+// stringList is a repeatable string flag.
+type stringList []string
+
+func (s *stringList) String() string { return strings.Join(*s, ",") }
+
+func (s *stringList) Set(v string) error {
+	for _, p := range strings.Split(v, ",") {
+		if p = strings.TrimSpace(p); p != "" {
+			*s = append(*s, p)
+		}
+	}
+	return nil
+}
+
+// devFlagSet is a FlagSet that prints its own usage to stderr.
+func devFlagSet(name string) *flag.FlagSet {
+	fs := flag.NewFlagSet("nmon-devtools "+name, flag.ContinueOnError)
+	fs.SetOutput(os.Stderr)
+	return fs
+}
+
+// httpJSON sends an optional JSON body and decodes a 2xx JSON reply into out (nil to discard it).
+func httpJSON(ctx context.Context, hc *http.Client, method, url string, in, out any) error {
+	var body io.Reader
+	if in != nil {
+		b, err := json.Marshal(in)
+		if err != nil {
+			return err
+		}
+		body = strings.NewReader(string(b))
+	}
+	req, err := http.NewRequestWithContext(ctx, method, url, body)
+	if err != nil {
+		return err
+	}
+	if in != nil {
+		req.Header.Set("Content-Type", "application/json")
+	}
+	resp, err := hc.Do(req)
+	if err != nil {
+		return err
+	}
+	defer func() { _ = resp.Body.Close() }() // body read to the end below
+	data, err := io.ReadAll(io.LimitReader(resp.Body, 64<<20))
+	if err != nil {
+		return err
+	}
+	if resp.StatusCode/100 != 2 {
+		return fmt.Errorf("%s %s: %s: %s", method, url, resp.Status, strings.TrimSpace(string(data[:min(len(data), 300)])))
+	}
+	if out == nil {
+		return nil
+	}
+	return json.Unmarshal(data, out)
+}
+
+func sleepCtx(ctx context.Context, d time.Duration) bool {
+	t := time.NewTimer(d)
+	defer t.Stop()
+	select {
+	case <-ctx.Done():
+		return false
+	case <-t.C:
+		return true
+	}
+}

cmd/nmon-devtools/pattern.go

@@ -0,0 +1,69 @@
+package main
+
+import (
+	"math"
+	"time"
+)
+
+// Synthetic traffic shapes for `nmon devtools backfill`. Everything here is a
+// pure function of its inputs, so a back-fill is reproducible and testable.
+
+const (
+	patternDiurnal = "diurnal"
+	patternFlat    = "flat"
+)
+
+// splitmix64 is a tiny deterministic hash used for noise; math/rand would make
+// two runs differ and a global source would be shared state.
+func splitmix64(x uint64) uint64 {
+	x += 0x9e3779b97f4a7c15
+	x = (x ^ (x >> 30)) * 0xbf58476d1ce4e5b9
+	x = (x ^ (x >> 27)) * 0x94d049bb133111eb
+	return x ^ (x >> 31)
+}
+
+// unit maps a hash to [0, 1).
+func unit(h uint64) float64 { return float64(h>>11) / (1 << 53) }
+
+// rateFactor is the multiple of the mean rate at t: 1 for "flat"; for
+// "diurnal" an evening peak (about 20:00 UTC), an early-morning trough, quieter
+// weekends, per-sample noise and the odd short burst.
+func rateFactor(pattern string, t time.Time, salt uint64) float64 {
+	if pattern == patternFlat {
+		return 1
+	}
+	h := float64(t.Hour()) + float64(t.Minute())/60
+	f := 1 + 0.6*math.Cos(2*math.Pi*(h-20)/24)
+	if wd := t.Weekday(); wd == time.Saturday || wd == time.Sunday {
+		f *= 0.8
+	}
+	slot := uint64(t.Unix() / 60)
+	f *= 0.88 + 0.24*unit(splitmix64(salt^slot))
+	if unit(splitmix64(salt^(slot/4)^0xb5ad4eceda1ce2a9)) < 0.01 { // ~1% of 4-minute slots burst
+		f *= 2.5
+	}
+	return math.Max(f, 0.05)
+}
+
+// counterSeries returns n cumulative octet-counter values, one per step from
+// start, beginning at 0 and never decreasing. mean is bytes per second.
+func counterSeries(pattern string, start time.Time, n int, step time.Duration, mean float64, salt uint64) []float64 {
+	out := make([]float64, n)
+	var total float64
+	for i := 1; i < n; i++ {
+		t := start.Add(time.Duration(i) * step)
+		total += mean * rateFactor(pattern, t, salt) * step.Seconds()
+		out[i] = math.Floor(total)
+	}
+	return out
+}
+
+// defaultMeanBytesPerSec is a stable per-interface mean (2 to 60 Mbit/s) for when
+// the live rate is unknown.
+func defaultMeanBytesPerSec(iface string, salt uint64) float64 {
+	h := salt
+	for _, c := range []byte(iface) {
+		h = splitmix64(h ^ uint64(c))
+	}
+	return (2 + 58*unit(h)*unit(h>>7)) * 125_000
+}

cmd/nmon-devtools/pattern_test.go

@@ -0,0 +1,56 @@
+package main
+
+import (
+	"testing"
+	"time"
+)
+
+func TestCounterSeriesIsMonotonicAndDeterministic(t *testing.T) {
+	start := time.Date(2026, 9, 1, 0, 0, 0, 0, time.UTC)
+	a := counterSeries(patternDiurnal, start, 3*24*60, time.Minute, 1_000_000, 7)
+	b := counterSeries(patternDiurnal, start, 3*24*60, time.Minute, 1_000_000, 7)
+	for i := range a {
+		if a[i] != b[i] {
+			t.Fatalf("not deterministic at %d", i)
+		}
+		if i > 0 && a[i] < a[i-1] {
+			t.Fatalf("decreased at %d", i)
+		}
+	}
+	if a[0] != 0 {
+		t.Fatalf("starts at %v, want 0", a[0])
+	}
+	meanRate := a[len(a)-1] / (float64(len(a)-1) * 60)
+	if meanRate < 0.8e6 || meanRate > 1.4e6 {
+		t.Fatalf("mean rate %.0f B/s drifted from 1e6", meanRate)
+	}
+}
+
+func TestDiurnalEveningBusierThanNight(t *testing.T) {
+	// Monday, so the weekend factor does not interfere. Averaged over many days the noise washes out.
+	var night, evening float64
+	for d := 0; d < 28; d++ {
+		day := time.Date(2026, 9, 7, 0, 0, 0, 0, time.UTC).AddDate(0, 0, d)
+		if wd := day.Weekday(); wd == time.Saturday || wd == time.Sunday {
+			continue
+		}
+		night += rateFactor(patternDiurnal, day.Add(5*time.Hour), 1)
+		evening += rateFactor(patternDiurnal, day.Add(20*time.Hour), 1)
+	}
+	if evening < 2*night {
+		t.Fatalf("evening %.2f is not clearly busier than night %.2f", evening, night)
+	}
+}
+
+func TestFlatPatternIsConstant(t *testing.T) {
+	if f := rateFactor(patternFlat, time.Now(), 3); f != 1 {
+		t.Fatalf("flat factor %v", f)
+	}
+}
+
+func TestDefaultMeanIsStableAndBounded(t *testing.T) {
+	m := defaultMeanBytesPerSec("01abc", 1)
+	if m != defaultMeanBytesPerSec("01abc", 1) || m < 2*125_000 || m > 60*125_000 {
+		t.Fatalf("mean %v", m)
+	}
+}

cmd/nmon-devtools/seed.go

@@ -0,0 +1,242 @@
+package main
+
+import (
+	"bytes"
+	"context"
+	"errors"
+	"fmt"
+	"net/http"
+	"net/url"
+	"os"
+	"strings"
+	"sync"
+	"time"
+
+	"github.com/v10networks/nmon/internal/profile"
+	"github.com/v10networks/nmon/internal/simagent"
+)
+
+// seedConfig is the command line of `devtools seed-demo`.
+type seedConfig struct {
+	api, hotURL string
+	days        int
+	step        time.Duration
+	countersRec string
+	envOut      string
+	profilesDir string
+	workers     int
+	hc          *http.Client
+}
+
+// seeded is one device after it was added to nmon.
+type seeded struct {
+	demoDevice
+	slug   string
+	agent  *simagent.Agent
+	ip     string
+	ifaces []seedIface
+}
+
+type seedIface struct {
+	ID         string `json:"id"`
+	Name       string `json:"ifname"`
+	HC         bool   `json:"has_hc_counters"`
+	Excluded   bool   `json:"excluded"`
+	Unreliable bool   `json:"unreliable"`
+}
+
+func (i seedIface) graphable() bool { return i.HC && !i.Excluded && !i.Unreliable }
+
+func seedDemoCmd(ctx context.Context, args []string) error {
+	cfg := seedConfig{hc: &http.Client{Timeout: 3 * time.Minute}}
+	fs := devFlagSet("seed-demo")
+	fs.StringVar(&cfg.api, "api", "http://127.0.0.1:8443", "base URL of the running nmon (started with --insecure-http)")
+	fs.StringVar(&cfg.hotURL, "hot-url", "", "base URL of the hot VictoriaMetrics, for the back-fill (required)")
+	fs.IntVar(&cfg.days, "days", 31, "days of history to back-fill")
+	fs.DurationVar(&cfg.step, "step", 60*time.Second, "back-fill sample spacing")
+	fs.StringVar(&cfg.countersRec, "counters-rec", "testdata/snmprec/counters.snmprec", "the counters fixture recording")
+	fs.StringVar(&cfg.envOut, "env-out", "", "write NMON_DEVICE=<counters slug> and NMON_DEVICE_48=<48-port slug> to this file when ready")
+	fs.StringVar(&cfg.profilesDir, "profiles-dir", "", "operator profiles directory (shipped profiles are always loaded)")
+	fs.IntVar(&cfg.workers, "workers", 6, "parallel back-fill workers")
+	if err := fs.Parse(args); err != nil {
+		return flagErr(err)
+	}
+	if cfg.hotURL == "" {
+		return errors.New("--hot-url is required")
+	}
+	cfg.api, cfg.hotURL = strings.TrimRight(cfg.api, "/"), strings.TrimRight(cfg.hotURL, "/")
+	return cfg.run(ctx)
+}
+
+func (c *seedConfig) run(ctx context.Context) error {
+	set, err := profile.Load(c.profilesDir)
+	if err != nil {
+		return err
+	}
+	fleet, err := buildFleet(set, c.countersRec)
+	if err != nil {
+		return err
+	}
+	var pool simagent.Pool
+	defer func() { _ = pool.Close() }() // process is exiting
+	added, err := c.addAll(ctx, &pool, fleet)
+	if err != nil {
+		return err
+	}
+	if err := c.backfillAll(ctx, added); err != nil {
+		return err
+	}
+	if err := c.writeEnv(added); err != nil {
+		return err
+	}
+	fmt.Println("seed-demo ready: agents keep answering until interrupted")
+	<-ctx.Done()
+	return nil
+}
+
+// addAll starts one agent per device on [::1] with its own port and adds the
+// device through the API with that port.
+func (c *seedConfig) addAll(ctx context.Context, pool *simagent.Pool, fleet []demoDevice) ([]seeded, error) {
+	var out []seeded
+	for i, d := range fleet {
+		cfg := simagent.Config{Addr: "[::1]:0", Recording: d.rec, Community: d.community}
+		if err := pool.Start(ctx, []simagent.Config{cfg}); err != nil {
+			return nil, fmt.Errorf("%s: %w", d.name, err)
+		}
+		agent := pool.Agents()[i]
+		s, err := c.addDevice(ctx, d, "::1", int(agent.Addr().Port()))
+		s.agent = agent
+		if err != nil {
+			return nil, fmt.Errorf("add %s: %w", d.name, err)
+		}
+		fmt.Printf("added %-12s %-10s %s (%d interfaces)\n", d.name, d.kind, s.slug, len(s.ifaces))
+		out = append(out, s)
+	}
+	return out, nil
+}
+
+func (c *seedConfig) addDevice(ctx context.Context, d demoDevice, ip string, port int) (seeded, error) {
+	version := d.version
+	if version == "" {
+		version = "v2c"
+	}
+	body := map[string]any{
+		"name": d.name, "addresses": []string{ip}, "site": d.site, "role": d.role,
+		"snmp": map[string]any{"version": version, "community": d.community, "port": port},
+	}
+	var created struct {
+		Slug string `json:"slug"`
+	}
+	if err := httpJSON(ctx, c.hc, http.MethodPost, c.api+"/api/v1/devices", body, &created); err != nil {
+		return seeded{}, err
+	}
+	s := seeded{demoDevice: d, slug: created.Slug, ip: ip}
+	var got struct {
+		Interfaces []seedIface `json:"interfaces"`
+	}
+	if err := httpJSON(ctx, c.hc, http.MethodGet, c.api+"/api/v1/devices/"+url.PathEscape(created.Slug), nil, &got); err != nil {
+		return seeded{}, err
+	}
+	if len(got.Interfaces) == 0 {
+		return seeded{}, errors.New("discovery found no interfaces")
+	}
+	s.ifaces = got.Interfaces
+	return s, nil
+}
+
+// backfillAll waits for each device's first live samples, then writes history
+// for every graphable interface in parallel.
+func (c *seedConfig) backfillAll(ctx context.Context, devs []seeded) error {
+	type job struct{ dev, iface string }
+	var jobs []job
+	probe := &backfillConfig{hotURL: c.hotURL, hc: c.hc}
+	for _, d := range devs {
+		for _, i := range d.ifaces {
+			if d.hc && i.graphable() {
+				jobs = append(jobs, job{d.slug, i.ID})
+			}
+		}
+		if err := c.waitLive(ctx, probe, d); err != nil {
+			return err
+		}
+		if d.kind == "down" {
+			_ = d.agent.Close() // goes silent now, so it reads as down by the time the screenshots are taken
+		}
+	}
+	ch := make(chan job)
+	errs := make(chan error, len(jobs))
+	var wg sync.WaitGroup
+	for w := 0; w < max(1, c.workers); w++ {
+		wg.Add(1)
+		go func() {
+			defer wg.Done()
+			for j := range ch {
+				cfg := &backfillConfig{hotURL: c.hotURL, device: j.dev, days: c.days, step: c.step, pattern: patternDiurnal,
+					seed: 1, hc: c.hc, logf: func(string, ...any) {}}
+				errs <- cfg.backfillIface(ctx, j.iface)
+			}
+		}()
+	}
+	for _, j := range jobs {
+		ch <- j
+	}
+	close(ch)
+	wg.Wait()
+	close(errs)
+	for err := range errs {
+		if err != nil {
+			return err
+		}
+	}
+	fmt.Printf("back-filled %d interfaces, %d days at %s\n", len(jobs), c.days, c.step)
+	return nil
+}
+
+// waitLive blocks until the hot store holds two live samples of the device's
+// first graphable interface, so the back-fill can end where they begin.
+func (c *seedConfig) waitLive(ctx context.Context, probe *backfillConfig, d seeded) error {
+	if !d.hc {
+		return nil
+	}
+	var first string
+	for _, i := range d.ifaces {
+		if i.graphable() {
+			first = i.ID
+			break
+		}
+	}
+	if first == "" {
+		return nil
+	}
+	deadline := time.Now().Add(3 * time.Minute)
+	for time.Now().Before(deadline) {
+		live, err := probe.probe(ctx, "ifHCInOctets", first)
+		if err == nil && live.ok && live.rate > 0 {
+			return nil
+		}
+		if !sleepCtx(ctx, 2*time.Second) {
+			return ctx.Err()
+		}
+	}
+	return fmt.Errorf("%s: no live samples in the hot store after 3 minutes (is nmon polling? --poll-interval)", d.slug)
+}
+
+func (c *seedConfig) writeEnv(devs []seeded) error {
+	var b bytes.Buffer
+	for _, d := range devs {
+		switch d.kind {
+		case "counters":
+			fmt.Fprintf(&b, "NMON_DEVICE=%s\n", d.slug)
+		case "big":
+			fmt.Fprintf(&b, "NMON_DEVICE_48=%s\n", d.slug)
+		case "v1":
+			fmt.Fprintf(&b, "NMON_DEVICE_32BIT=%s\n", d.slug)
+		case "down":
+			fmt.Fprintf(&b, "NMON_DEVICE_DOWN=%s\n", d.slug)
+		}
+	}
+	if c.envOut == "" {
+		return nil
+	}
+	return os.WriteFile(c.envOut, b.Bytes(), 0o600)
+}

cmd/nmon-devtools/store.go

@@ -0,0 +1,84 @@
+package main
+
+import (
+	"bytes"
+	"context"
+	"encoding/json"
+	"fmt"
+	"io"
+	"net/http"
+	"time"
+
+	"github.com/v10networks/nmon/internal/metrics"
+)
+
+// parseExport reads VictoriaMetrics' /api/v1/export (JSON lines) and returns
+// the earliest sample of the first series.
+func parseExport(raw []byte) (liveSeries, error) {
+	line, _, _ := bytes.Cut(bytes.TrimSpace(raw), []byte("\n"))
+	if len(line) == 0 {
+		return liveSeries{}, nil
+	}
+	var s struct {
+		Values     []float64 `json:"values"`
+		Timestamps []int64   `json:"timestamps"`
+	}
+	if err := json.Unmarshal(line, &s); err != nil {
+		return liveSeries{}, fmt.Errorf("decode export: %w", err)
+	}
+	if len(s.Values) == 0 || len(s.Values) != len(s.Timestamps) {
+		return liveSeries{}, nil
+	}
+	out := liveSeries{ts: time.UnixMilli(s.Timestamps[0]).UTC(), val: s.Values[0], ok: true}
+	if len(s.Values) > 1 && s.Timestamps[1] > s.Timestamps[0] {
+		out.rate = (s.Values[1] - s.Values[0]) / (float64(s.Timestamps[1]-s.Timestamps[0]) / 1000)
+	}
+	return out, nil
+}
+
+func (c *backfillConfig) get(ctx context.Context, u string, dst io.Writer) error {
+	req, err := http.NewRequestWithContext(ctx, http.MethodGet, u, nil)
+	if err != nil {
+		return err
+	}
+	resp, err := c.hc.Do(req)
+	if err != nil {
+		return err
+	}
+	defer func() { _ = resp.Body.Close() }() // read to the end below
+	if resp.StatusCode != http.StatusOK {
+		b, _ := io.ReadAll(io.LimitReader(resp.Body, 300))
+		return fmt.Errorf("GET %s: %s: %s", u, resp.Status, b)
+	}
+	_, err = io.Copy(dst, resp.Body)
+	return err
+}
+
+// importBatch is how many samples go in one POST (about 5 MB of text).
+const importBatch = 50_000
+
+// send writes samples through /api/v1/import/prometheus in batches.
+func (c *backfillConfig) send(ctx context.Context, samples []metrics.Sample) error {
+	for len(samples) > 0 {
+		n := min(len(samples), importBatch)
+		body := make([]byte, 0, n*110)
+		for _, s := range samples[:n] {
+			body = metrics.AppendPromText(body, s)
+		}
+		req, err := http.NewRequestWithContext(ctx, http.MethodPost, c.hotURL+"/api/v1/import/prometheus", bytes.NewReader(body))
+		if err != nil {
+			return err
+		}
+		resp, err := c.hc.Do(req)
+		if err != nil {
+			return err
+		}
+		msg, _ := io.ReadAll(io.LimitReader(resp.Body, 300))
+		_ = resp.Body.Close() // reply already read
+		if resp.StatusCode/100 != 2 {
+			return fmt.Errorf("import: %s: %s", resp.Status, msg)
+		}
+		samples = samples[n:]
+	}
+	return nil
+}

cmd/nmon-librenms-import/main.go

@@ -0,0 +1,110 @@
+// Command nmon-librenms-import turns LibreNMS OS definitions into draft nmon
+// profiles. It runs offline, before nmon; nmon itself neither links nor exposes it.
+//
+//	nmon-librenms-import --librenms <checkout> --out <dir> [--os junos,ios,...] [--mibs-dir <dir>]...
+//
+// The drafts hold only type: unverified metrics. Review them, copy the ones you
+// want into <data-dir>/profiles/ and confirm them with `nmon profile test`.
+package main
+
+import (
+	"errors"
+	"flag"
+	"fmt"
+	"io"
+	"os"
+	"path/filepath"
+	"strings"
+	"text/tabwriter"
+
+	"github.com/v10networks/nmon/internal/cliout"
+	"github.com/v10networks/nmon/internal/librenms"
+)
+
+type listFlag []string
+
+func (l *listFlag) String() string { return strings.Join(*l, ",") }
+func (l *listFlag) Set(v string) error {
+	for _, s := range strings.Split(v, ",") {
+		if s = strings.TrimSpace(s); s != "" {
+			*l = append(*l, s)
+		}
+	}
+	return nil
+}
+
+func main() {
+	if err := run(os.Args[1:]); err != nil {
+		fmt.Fprintln(os.Stderr, "nmon-librenms-import:", err)
+		os.Exit(1)
+	}
+}
+
+func run(args []string) error {
+	fs := flag.NewFlagSet("nmon-librenms-import", flag.ContinueOnError)
+	var (
+		root, out string
+		oses      listFlag
+		mibDirs   listFlag
+	)
+	fs.StringVar(&root, "librenms", "", "path of a LibreNMS checkout (required)")
+	fs.StringVar(&out, "out", "", "directory to write <os>.yaml drafts into (required)")
+	fs.Var(&oses, "os", "comma-separated LibreNMS OS names, e.g. junos,ios (default: every OS)")
+	fs.Var(&mibDirs, "mibs-dir", "extra MIB directory searched before the checkout's mibs/; repeatable")
+	fs.Usage = func() {
+		// Usage text is best-effort; a failed write to the terminal has nowhere to go.
+		_, _ = fmt.Fprintln(fs.Output(), "usage: nmon-librenms-import --librenms DIR --out DIR [--os a,b] [--mibs-dir DIR]...")
+		fs.PrintDefaults()
+	}
+	if err := fs.Parse(args); err != nil {
+		if errors.Is(err, flag.ErrHelp) {
+			return nil
+		}
+		return err
+	}
+	if root == "" || out == "" || fs.NArg() > 0 {
+		fs.Usage()
+		return errors.New("--librenms and --out are required")
+	}
+	imp, err := librenms.New(librenms.Options{LibreNMS: root, MIBDirs: mibDirs})
+	if err != nil {
+		return err
+	}
+	if len(oses) == 0 {
+		if oses, err = imp.OSList(); err != nil {
+			return err
+		}
+	}
+	if err := os.MkdirAll(out, 0o755); err != nil {
+		return err
+	}
+	return importAll(imp, oses, out, os.Stderr)
+}
+
+// importAll imports each OS, writes its draft into out and prints a summary
+// table to w. Output failures count as failures of the run.
+func importAll(imp *librenms.Importer, oses []string, out string, w io.Writer) error {
+	tw := tabwriter.NewWriter(w, 0, 4, 2, ' ', 0)
+	cw := cliout.New(tw)
+	cw.Println("OS\tPROFILE\tMAPPED\tLABELS\tSKIPPED")
+	failed := 0
+	for _, name := range oses {
+		d, err := imp.Import(name)
+		if err != nil {
+			cw.Printf("%s\tERROR\t\t\t%v\n", name, err)
+			failed++
+			continue
+		}
+		if err := os.WriteFile(filepath.Join(out, d.Name+".yaml"), d.YAML, 0o644); err != nil {
+			return err
+		}
+		cw.Printf("%s\t%s\t%d\t%d\t%d\n", name, d.Name, d.Mapped, d.Helpers, len(d.Skipped))
+	}
+	if err := errors.Join(tw.Flush(), cw.Err()); err != nil {
+		return fmt.Errorf("write summary: %w", err)
+	}
+	if failed > 0 {
+		return fmt.Errorf("%d of %d OS definitions could not be imported", failed, len(oses))
+	}
+	return nil
+}

cmd/nmon-librenms-import/main_test.go

@@ -0,0 +1,42 @@
+package main
+
+import (
+	"os"
+	"path/filepath"
+	"strings"
+	"testing"
+
+	"github.com/v10networks/nmon/internal/profile"
+)
+
+func TestRunWritesLoadableDrafts(t *testing.T) {
+	root := filepath.Join("..", "..", "internal", "librenms", "testdata", "lnms")
+	out := t.TempDir()
+	if err := run([]string{"--librenms", root, "--out", out, "--os", "acme"}); err != nil {
+		t.Fatal(err)
+	}
+	b, err := os.ReadFile(filepath.Join(out, "acme.yaml"))
+	if err != nil {
+		t.Fatal(err)
+	}
+	if _, err := profile.Parse("acme.yaml", b); err != nil {
+		t.Fatalf("%v\n%s", err, b)
+	}
+	if !strings.Contains(string(b), "type: unverified") {
+		t.Error("draft metrics must be unverified")
+	}
+}
+
+func TestRunErrors(t *testing.T) {
+	root := filepath.Join("..", "..", "internal", "librenms", "testdata", "lnms")
+	for _, args := range [][]string{
+		{},
+		{"--librenms", root},
+		{"--librenms", t.TempDir(), "--out", t.TempDir()},
+		{"--librenms", root, "--out", t.TempDir(), "--os", "nosuchos"},
+	} {
+		if err := run(args); err == nil {
+			t.Errorf("%v: expected an error", args)
+		}
+	}
+}

cmd/nmon/discover.go

@@ -0,0 +1,124 @@
+package main
+
+import (
+	"bytes"
+	"context"
+	"encoding/json"
+	"fmt"
+	"io"
+	"net/http"
+	"net/url"
+	"os"
+	"strings"
+	"time"
+
+	"github.com/v10networks/nmon/internal/cliout"
+)
+
+func init() {
+	register("discover", "run discovery for a device now (asks a running nmon)", discoverCmd)
+}
+
+// discoverReport mirrors the API's DiscoverView.
+type discoverReport struct {
+	Profile        string `json:"profile"`
+	ProfileMissing string `json:"profile_missing"`
+	Partial        bool   `json:"partial"`
+	Tables         []struct {
+		Name, Status, Detail string
+		Rows                 int
+	} `json:"tables"`
+	Matched          int      `json:"interfaces_matched"`
+	New              int      `json:"interfaces_new"`
+	Retired          int      `json:"interfaces_retired"`
+	Split            int      `json:"interfaces_split"`
+	Unretired        int      `json:"interfaces_unretired"`
+	Reviews          int      `json:"identity_reviews_opened"`
+	HardwareReplaced bool     `json:"hardware_replaced"`
+	Warnings         []string `json:"warnings"`
+}
+
+func discoverCmd(ctx context.Context, args []string) error {
+	fs := profileFlagSet("discover", "discover <slug> [--api URL]")
+	fs.Usage = func() {
+		// Usage text is best-effort; a failed write to the terminal has nowhere to go.
+		_, _ = fmt.Fprintln(os.Stderr, "usage: nmon discover <slug> [--api URL] [--data-dir DIR]\n\n"+
+			"Asks the running nmon at --api to discover the device now and prints what changed.")
+		fs.PrintDefaults()
+	}
+	var api, dataDir string
+	var timeout time.Duration
+	fs.StringVar(&api, "api", "http://[::1]:8443", "base URL of the running nmon")
+	fs.StringVar(&dataDir, "data-dir", "", "accepted for symmetry with serve; the API of the running server is used")
+	fs.DurationVar(&timeout, "timeout", 60*time.Second, "how long to wait for the discovery")
+	pos, err := parseInterspersed(fs, args)
+	if err != nil {
+		return flagErr(err)
+	}
+	if len(pos) != 1 {
+		return fmt.Errorf("usage: nmon discover <slug> [--api URL]")
+	}
+	rep, err := requestDiscover(ctx, api, pos[0], timeout)
+	if err != nil {
+		return err
+	}
+	return rep.print(os.Stdout, pos[0])
+}
+
+func requestDiscover(ctx context.Context, api, slug string, timeout time.Duration) (*discoverReport, error) {
+	ctx, cancel := context.WithTimeout(ctx, timeout)
+	defer cancel()
+	u := strings.TrimRight(api, "/") + "/api/v1/devices/" + url.PathEscape(slug) + "/discover"
+	req, err := http.NewRequestWithContext(ctx, http.MethodPost, u, bytes.NewReader(nil))
+	if err != nil {
+		return nil, err
+	}
+	resp, err := http.DefaultClient.Do(req)
+	if err != nil {
+		return nil, fmt.Errorf("cannot reach nmon at %s (is it running? use --api): %w", api, err)
+	}
+	defer func() { _ = resp.Body.Close() }() // body fully read below; a close error changes nothing
+	body, _ := io.ReadAll(io.LimitReader(resp.Body, 4<<20))
+	if resp.StatusCode != http.StatusOK {
+		var p struct{ Title, Detail string }
+		_ = json.Unmarshal(body, &p)
+		msg := p.Detail
+		if msg == "" {
+			msg = p.Title
+		}
+		return nil, fmt.Errorf("%s: %d %s", slug, resp.StatusCode, msg)
+	}
+	var rep discoverReport
+	if err := json.Unmarshal(body, &rep); err != nil {
+		return nil, err
+	}
+	return &rep, nil
+}
+
+func (r *discoverReport) print(out io.Writer, slug string) error {
+	w := cliout.New(out)
+	w.Printf("discovered %s: profile %s\n", slug, r.Profile)
+	if r.ProfileMissing != "" {
+		w.Printf("  profile %q no longer exists; generic is in use\n", r.ProfileMissing)
+	}
+	w.Printf("  interfaces: %d matched, %d new, %d retired, %d unretired, %d split\n",
+		r.Matched, r.New, r.Retired, r.Unretired, r.Split)
+	if r.Reviews > 0 {
+		w.Printf("  %d identity review(s) opened: nothing was merged automatically\n", r.Reviews)
+	}
+	if r.HardwareReplaced {
+		w.Println("  hardware replaced: chassis serial changed, history continues (review opened)")
+	}
+	for _, t := range r.Tables {
+		if t.Status != "ok" {
+			w.Printf("  table %s: %s %s\n", t.Name, t.Status, t.Detail)
+		}
+	}
+	if r.Partial {
+		w.Println("  PARTIAL: a table overran its limit; its previous result was kept")
+	}
+	for _, x := range r.Warnings {
+		w.Printf("  warning: %s\n", x)
+	}
+	return w.Err()
+}

cmd/nmon/migrate.go

@@ -44,7 +44,7 @@ func migrate(ctx context.Context, args []string) error {
 	if err != nil {
 		return err
 	}
-	defer st.Close()
+	defer func() { _ = st.Close() }() // migrations are committed; a close error changes nothing
 	if action == "down" {
 		if err := st.Rollback(ctx); err != nil {
 			return err

cmd/nmon/openapi.go

@@ -0,0 +1,25 @@
+package main
+
+import (
+	"context"
+	"fmt"
+	"os"
+
+	"github.com/v10networks/nmon/internal/app"
+)
+
+func init() {
+	register("openapi", "print the generated OpenAPI 3.1 document (nmon openapi > openapi.json)", openapiCmd)
+}
+
+func openapiCmd(_ context.Context, args []string) error {
+	if len(args) > 0 {
+		return fmt.Errorf("openapi takes no arguments, got %q", args[0])
+	}
+	spec, err := app.OpenAPISpec()
+	if err != nil {
+		return fmt.Errorf("generate spec: %w", err)
+	}
+	_, err = fmt.Fprintf(os.Stdout, "%s\n", spec)
+	return err
+}

cmd/nmon/profile.go

@@ -0,0 +1,78 @@
+package main
+
+import (
+	"context"
+	"flag"
+	"fmt"
+	"io"
+	"os"
+	"strings"
+)
+
+func init() {
+	register("profile", "test, record and draft device profiles", profileCmd)
+}
+
+const profileUsage = `usage: nmon profile <subcommand> [flags]
+
+subcommands:
+  new      compile MIB objects into draft profile metrics (--mib MODULE)
+  record   read-only SNMP walk of a device into a redacted .snmprec file
+  test     discovery plus one poll with the matching profile
+`
+
+func profileCmd(ctx context.Context, args []string) error {
+	if len(args) == 0 || args[0] == "-h" || args[0] == "--help" || args[0] == "help" {
+		fmt.Fprint(os.Stderr, profileUsage)
+		if len(args) == 0 {
+			os.Exit(2)
+		}
+		return nil
+	}
+	switch args[0] {
+	case "new":
+		return profileNew(ctx, args[1:], os.Stdout)
+	case "record":
+		return profileRecord(ctx, args[1:], os.Stdout)
+	case "test":
+		return profileTest(ctx, args[1:], os.Stdout)
+	}
+	fmt.Fprint(os.Stderr, profileUsage)
+	return fmt.Errorf("profile: unknown subcommand %q", args[0])
+}
+
+// listFlag is a repeatable string flag that also accepts comma-separated values.
+type listFlag []string
+
+func (l *listFlag) String() string { return strings.Join(*l, ",") }
+func (l *listFlag) Set(v string) error {
+	for _, s := range strings.Split(v, ",") {
+		if s = strings.TrimSpace(s); s != "" {
+			*l = append(*l, s)
+		}
+	}
+	return nil
+}
+
+// parseInterspersed parses flags that may come before or after positional arguments.
+func parseInterspersed(fs *flag.FlagSet, args []string) ([]string, error) {
+	var pos []string
+	for {
+		if err := fs.Parse(args); err != nil {
+			return nil, err
+		}
+		args = fs.Args()
+		if len(args) == 0 {
+			return pos, nil
+		}
+		pos = append(pos, args[0])
+		args = args[1:]
+	}
+}
+
+// profileFlagSet returns a FlagSet that prints its usage to stderr.
+func profileFlagSet(name, usage string) *flag.FlagSet {
+	fs := newFlagSet("profile "+name, usage)
+	fs.SetOutput(io.Writer(os.Stderr))
+	return fs
+}

cmd/nmon/profile_new.go

@@ -0,0 +1,483 @@
+package main
+
+import (
+	"context"
+	"fmt"
+	"io"
+	"os"
+	"path/filepath"
+	"regexp"
+	"slices"
+	"sort"
+	"strconv"
+	"strings"
+
+	"github.com/v10networks/nmon/internal/mib"
+)
+
+const defaultSystemMIBs = "/usr/share/nmon/mibs"
+
+// mibSearchPath returns the directories to read MIBs from: explicit --mibs-dir
+// values, else <data-dir>/mibs followed by the system location.
+func mibSearchPath(explicit []string, dataDir string) ([]string, error) {
+	if len(explicit) > 0 {
+		for _, d := range explicit {
+			if st, err := os.Stat(d); err != nil || !st.IsDir() {
+				return nil, fmt.Errorf("--mibs-dir %s: not a directory", d)
+			}
+		}
+		return explicit, nil
+	}
+	var out []string
+	var cands []string
+	if dataDir != "" {
+		cands = append(cands, filepath.Join(dataDir, "mibs"))
+	}
+	cands = append(cands, defaultSystemMIBs)
+	for _, d := range cands {
+		if st, err := os.Stat(d); err == nil && st.IsDir() {
+			out = append(out, d)
+		}
+	}
+	if len(out) == 0 {
+		return nil, fmt.Errorf("no MIB directory found (looked in %s); pass --mibs-dir", strings.Join(cands, ", "))
+	}
+	return out, nil
+}
+
+func profileNew(_ context.Context, args []string, stdout io.Writer) error {
+	fs := profileFlagSet("new",
+		"profile new --mib MODULE [--table NAME] [--objects a,b] [--mibs-dir DIR]... [--data-dir DIR] [--out FILE]")
+	var (
+		module, tableName, out, dataDir string
+		objects, mibsDirs               listFlag
+	)
+	fs.StringVar(&module, "mib", "", "MIB module to compile, e.g. IF-MIB (required)")
+	fs.StringVar(&tableName, "table", "", "compile every readable column of this table")
+	fs.Var(&objects, "objects", "comma-separated object names (NAME or MODULE::NAME); repeatable")
+	fs.Var(&mibsDirs, "mibs-dir",
+		"directory of MIB files, searched recursively; repeatable (default <data-dir>/mibs, then "+defaultSystemMIBs+")")
+	fs.StringVar(&dataDir, "data-dir", "", "nmon data folder; its mibs/ subfolder is searched")
+	fs.StringVar(&out, "out", "", "write the draft here instead of stdout")
+	rest, err := parseInterspersed(fs, args)
+	if err != nil {
+		return flagErr(err)
+	}
+	if len(rest) > 0 {
+		return fmt.Errorf("unexpected argument %q", rest[0])
+	}
+	if module == "" {
+		return fmt.Errorf("--mib is required")
+	}
+	path, err := mibSearchPath(mibsDirs, dataDir)
+	if err != nil {
+		return err
+	}
+	l := mib.NewLoader(path...)
+	draft, err := draftProfile(l, draftSpec{Module: module, Table: tableName, Objects: objects})
+	if err != nil {
+		return err
+	}
+	if out != "" {
+		return os.WriteFile(out, draft, 0o644)
+	}
+	_, err = stdout.Write(draft)
+	return err
+}
+
+type draftSpec struct {
+	Module  string
+	Table   string
+	Objects []string
+}
+
+// unitMap maps UNITS clauses (lower case) to the profile unit vocabulary, with
+// the scale that converts the MIB's unit to it.
+var unitMap = map[string]struct {
+	unit  string
+	scale float64
+}{
+	"seconds": {"seconds", 0}, "second": {"seconds", 0}, "secs": {"seconds", 0}, "sec": {"seconds", 0},
+	"minutes": {"minutes", 0}, "minute": {"minutes", 0},
+	"degrees celsius": {"celsius", 0}, "degrees centigrade": {"celsius", 0}, "celsius": {"celsius", 0},
+	"degrees c": {"celsius", 0}, "deg c": {"celsius", 0},
+	"volts": {"volts", 0}, "volt": {"volts", 0}, "millivolts": {"volts", 0.001}, "mv": {"volts", 0.001},
+	"amperes": {"amps", 0}, "amps": {"amps", 0}, "amp": {"amps", 0}, "milliamperes": {"amps", 0.001},
+	"milliamps": {"amps", 0.001}, "ma": {"amps", 0.001},
+	"watts": {"watts", 0}, "watt": {"watts", 0}, "milliwatts": {"watts", 0.001}, "mw": {"watts", 0.001},
+	"dbm": {"dbm", 0},
+	"rpm": {"rpm", 0}, "revolutions per minute": {"rpm", 0},
+	"percent": {"percent", 0}, "%": {"percent", 0}, "percentage": {"percent", 0},
+	"bytes": {"bytes", 0}, "octets": {"octets", 0}, "kilobytes": {"bytes", 1024}, "megabytes": {"bytes", 1048576},
+	"bits": {"bits", 0}, "bits per second": {"bps", 0}, "bps": {"bps", 0}, "kilobits per second": {"bps", 1000},
+	"packets": {"packets", 0}, "errors": {"errors", 0},
+	"hertz": {"hertz", 0}, "hz": {"hertz", 0},
+}
+
+var hintRE = regexp.MustCompile(`^d-([0-9]+)$`)
+
+type draftMetric struct {
+	obj      *mib.Object
+	label    string // index_label column
+	labelAs  string
+	comments []string
+	typ      string
+	unit     string
+	scale    float64
+	enum     map[int]string
+}
+
+// draftProfile compiles the selected objects into a complete profile document
+// whose unit and interval are TODO so that profile.Parse refuses it until a human fills them in.
+func draftProfile(l *mib.Loader, spec draftSpec) ([]byte, error) {
+	m, err := l.Load(spec.Module)
+	if err != nil {
+		return nil, err
+	}
+	objs, err := selectObjects(l, m, spec)
+	if err != nil {
+		return nil, err
+	}
+	return []byte(renderDraft(spec, m, draftMetrics(l, m, objs))), nil
+}
+
+// selectObjects picks the objects to compile: a table's readable columns, the
+// named objects, or (when neither is given) every readable scalar and column.
+// The result is sorted by OID.
+func selectObjects(l *mib.Loader, m *mib.Module, spec draftSpec) ([]*mib.Object, error) {
+	chosen := map[string]*mib.Object{}
+	add := func(o *mib.Object) { chosen[o.Module+"::"+o.Name] = o }
+	if spec.Table != "" {
+		cols, err := tableColumns(m, spec)
+		if err != nil {
+			return nil, err
+		}
+		for _, o := range cols {
+			add(o)
+		}
+	}
+	named, err := namedObjects(l, spec)
+	if err != nil {
+		return nil, err
+	}
+	for _, o := range named {
+		add(o)
+	}
+	if spec.Table == "" && len(spec.Objects) == 0 {
+		for _, o := range allReadable(m) {
+			add(o)
+		}
+	}
+	if len(chosen) == 0 {
+		return nil, fmt.Errorf("%s: no readable scalar or column objects selected", spec.Module)
+	}
+	objs := make([]*mib.Object, 0, len(chosen))
+	for _, o := range chosen {
+		objs = append(objs, o)
+	}
+	sort.Slice(objs, func(i, j int) bool { return oidLess(objs[i].OID, objs[j].OID) })
+	return objs, nil
+}
+
+// allReadable lists every current, readable scalar and column of m.
+func allReadable(m *mib.Module) []*mib.Object {
+	var out []*mib.Object
+	for _, o := range m.Objects {
+		if (o.Kind == mib.KindScalar || o.Kind == mib.KindColumn) && readable(o) && o.Status != "obsolete" && o.OID != "" {
+			out = append(out, o)
+		}
+	}
+	return out
+}
+
+// tableColumns lists the readable columns of spec.Table.
+func tableColumns(m *mib.Module, spec draftSpec) ([]*mib.Object, error) {
+	tb := m.Lookup(spec.Table)
+	if tb == nil || tb.Kind != mib.KindTable {
+		return nil, fmt.Errorf("%s: no table %q (tables are %s)", spec.Module, spec.Table, strings.Join(tableNames(m), ", "))
+	}
+	var cols []*mib.Object
+	for _, o := range m.Objects {
+		if o.Kind == mib.KindColumn && o.Table == spec.Table && readable(o) {
+			cols = append(cols, o)
+		}
+	}
+	return cols, nil
+}
+
+// namedObjects resolves --objects entries; a bare NAME belongs to spec.Module.
+func namedObjects(l *mib.Loader, spec draftSpec) ([]*mib.Object, error) {
+	var out []*mib.Object
+	for _, n := range spec.Objects {
+		q := n
+		if !strings.Contains(q, "::") {
+			q = spec.Module + "::" + n
+		}
+		o, err := l.Object(q)
+		if err != nil {
+			return nil, err
+		}
+		if o.Kind != mib.KindScalar && o.Kind != mib.KindColumn {
+			return nil, fmt.Errorf("%s is a %s, not a scalar or table column", q, o.Kind)
+		}
+		out = append(out, o)
+	}
+	return out, nil
+}
+
+// draftMetrics converts objs to draft metrics. Label columns used by
+// index_label must exist as metrics of the profile, so the ones not already
+// selected are appended, sorted by OID.
+func draftMetrics(l *mib.Loader, m *mib.Module, objs []*mib.Object) []draftMetric {
+	labels := map[string]*mib.Object{}
+	var metrics []draftMetric
+	have := map[string]bool{}
+	for _, o := range objs {
+		have[o.Name] = true
+	}
+	for _, o := range objs {
+		dm := convert(o)
+		if o.Kind == mib.KindColumn {
+			if lo := setLabel(&dm, l, m, o); lo != nil && !have[lo.Name] {
+				labels[lo.Name] = lo
+			}
+		}
+		metrics = append(metrics, dm)
+	}
+	var extra []*mib.Object
+	for _, o := range labels {
+		extra = append(extra, o)
+	}
+	sort.Slice(extra, func(i, j int) bool { return oidLess(extra[i].OID, extra[j].OID) })
+	for _, o := range extra {
+		dm := convert(o)
+		dm.comments = append(dm.comments, "added as the index_label column of the metrics above")
+		metrics = append(metrics, dm)
+	}
+	return metrics
+}
+
+// setLabel fills dm's index_label from labelFor. It returns the label column
+// when the profile must carry it as a metric of its own (a component label), else nil.
+func setLabel(dm *draftMetric, l *mib.Loader, m *mib.Module, o *mib.Object) *mib.Object {
+	col, as, note := labelFor(l, m, o)
+	dm.label, dm.labelAs = col, as
+	if note != "" {
+		dm.comments = append(dm.comments, note)
+	}
+	if as != "component" {
+		return nil
+	}
+	return m.Lookup(col)
+}
+
+// renderDraft writes the profile YAML document.
+func renderDraft(spec draftSpec, m *mib.Module, metrics []draftMetric) string {
+	var b strings.Builder
+	name := "draft-" + strings.ToLower(spec.Module)
+	fmt.Fprintf(&b, "# DRAFT compiled by `nmon profile new` from %s (%s).\n", spec.Module, filepath.Base(m.File))
+	fmt.Fprintf(&b, "# Save as %s.yaml. Replace every TODO (unit, interval, index_label) and add a match: section.\n", name)
+	b.WriteString("# The loader rejects TODO on purpose, so an unreviewed draft can never be polled.\n")
+	fmt.Fprintf(&b, "name: %s\nextends: generic\nprovenance: %q\nmetrics:\n", name,
+		"drafted by nmon profile new from "+spec.Module+"; review before use")
+	for _, dm := range metrics {
+		writeDraftMetric(&b, dm)
+	}
+	return b.String()
+}
+
+func tableNames(m *mib.Module) []string {
+	var out []string
+	for _, o := range m.Objects {
+		if o.Kind == mib.KindTable {
+			out = append(out, o.Name)
+		}
+	}
+	return out
+}
+
+func readable(o *mib.Object) bool {
+	switch o.Access {
+	case "read-only", "read-write", "read-create", "mandatory", "":
+		return o.Access != "" || o.Kind == mib.KindScalar
+	}
+	return false
+}
+
+func oidLess(a, b string) bool {
+	as, bs := strings.Split(a, "."), strings.Split(b, ".")
+	for i := 0; i < len(as) && i < len(bs); i++ {
+		x, _ := strconv.Atoi(as[i])
+		y, _ := strconv.Atoi(bs[i])
+		if x != y {
+			return x < y
+		}
+	}
+	return len(as) < len(bs)
+}
+
+// convert maps one MIB object to a draft metric.
+func convert(o *mib.Object) draftMetric {
+	dm := draftMetric{obj: o, unit: "TODO"}
+	if o.TC != "" || o.DisplayHint != "" {
+		dm.comments = append(dm.comments, conventionNote(o))
+	}
+	applyBaseType(&dm, o)
+	if o.Units != "" {
+		if u, ok := unitMap[strings.ToLower(o.Units)]; ok && dm.typ != "status" && dm.typ != "text" {
+			dm.unit, dm.scale = u.unit, u.scale
+		} else {
+			dm.comments = append(dm.comments, "UNITS "+strconv.Quote(o.Units)+" is not in the unit vocabulary")
+		}
+	}
+	return dm
+}
+
+// conventionNote describes the textual convention and DISPLAY-HINT, and
+// suggests a scale when the hint implies decimal places ("d-2").
+func conventionNote(o *mib.Object) string {
+	c := "textual convention " + o.TC
+	if o.TC == "" {
+		c = "no textual convention"
+	}
+	if o.DisplayHint != "" {
+		c += ", DISPLAY-HINT " + strconv.Quote(o.DisplayHint)
+	}
+	if mm := hintRE.FindStringSubmatch(o.DisplayHint); mm != nil {
+		n, _ := strconv.Atoi(mm[1])
+		s := "0." + strings.Repeat("0", n-1) + "1"
+		if n == 0 {
+			s = "1"
+		}
+		c += "; the value has " + mm[1] + " implied decimal place(s), suggest scale: " + s
+	}
+	return c
+}
+
+// applyBaseType sets the metric type (and unit where the type implies one)
+// from the object's SMI base type.
+func applyBaseType(dm *draftMetric, o *mib.Object) {
+	switch o.BaseType {
+	case mib.BaseCounter64:
+		dm.typ = "counter64"
+	case mib.BaseCounter32:
+		dm.typ = "counter32"
+	case mib.BaseGauge32, mib.BaseUnsigned32, mib.BaseInteger32, mib.BaseInteger:
+		if len(o.Enum) > 0 {
+			dm.typ, dm.unit, dm.enum = "status", "enum", o.Enum
+		} else {
+			dm.typ = "gauge"
+		}
+	case mib.BaseTimeTicks:
+		dm.typ, dm.unit = "gauge", "seconds"
+		dm.comments = append(dm.comments, "TimeTicks: the poller converts to seconds")
+	case mib.BaseOctets:
+		dm.typ, dm.unit = "text", "text"
+	case mib.BaseOID, mib.BaseIPAddress, mib.BaseOpaque, mib.BaseBits:
+		dm.typ, dm.unit = "text", "text"
+		dm.comments = append(dm.comments, o.BaseType+" is collected as text")
+	default:
+		dm.typ = "gauge"
+		dm.comments = append(dm.comments, fmt.Sprintf("base type of %q could not be determined; check the type", o.TC))
+	}
+}
+
+var labelNameRE = regexp.MustCompile(`(?i)(descr|name|label|alias)`)
+
+// labelFor picks the index_label for a table column: ifIndex-indexed tables are
+// labelled by interface; otherwise the first DisplayString-like column of the table.
+func labelFor(l *mib.Loader, m *mib.Module, o *mib.Object) (col, as, note string) {
+	if indexedByIfIndex(l, m, o) {
+		return "ifIndex", "iface", ""
+	}
+	if best := bestLabelColumn(m, o); best != nil {
+		return best.Name, "component", ""
+	}
+	return "TODO", "component", "no DisplayString column found in the table: set index_label.column"
+}
+
+// indexedByIfIndex follows AUGMENTS (up to 4 rows deep) looking for ifIndex in the row's INDEX.
+func indexedByIfIndex(l *mib.Loader, m *mib.Module, o *mib.Object) bool {
+	row := rowOf(m, o)
+	for depth := 0; row != nil && depth < 4; depth++ {
+		if slices.Contains(row.Index, "ifIndex") {
+			return true
+		}
+		if row.Augments == "" {
+			break
+		}
+		next := m.Lookup(row.Augments) // AUGMENTS: the row shares the augmented row's index
+		if next == nil {
+			next, _ = l.Object(row.Augments)
+		}
+		row = next
+	}
+	return false
+}
+
+// bestLabelColumn is the lowest-OID readable string column of o's table that
+// looks like a name (DisplayString, a text DISPLAY-HINT or a descr/name/label/alias name).
+func bestLabelColumn(m *mib.Module, o *mib.Object) *mib.Object {
+	var best *mib.Object
+	for _, c := range m.Objects {
+		if c.Kind != mib.KindColumn || c.Table != o.Table || !readable(c) || c.BaseType != mib.BaseOctets {
+			continue
+		}
+		if c.TC != "DisplayString" && !strings.HasSuffix(c.DisplayHint, "a") && !labelNameRE.MatchString(c.Name) {
+			continue
+		}
+		if best == nil || oidLess(c.OID, best.OID) {
+			best = c
+		}
+	}
+	return best
+}
+
+func rowOf(m *mib.Module, col *mib.Object) *mib.Object {
+	i := strings.LastIndexByte(col.OID, '.')
+	if i < 0 {
+		return nil
+	}
+	for _, o := range m.Objects {
+		if o.Kind == mib.KindRow && o.OID == col.OID[:i] {
+			return o
+		}
+	}
+	return nil
+}
+
+func writeDraftMetric(b *strings.Builder, dm draftMetric) {
+	o := dm.obj
+	oid := o.OID
+	if o.Kind == mib.KindScalar {
+		oid += ".0"
+	}
+	for _, c := range dm.comments {
+		fmt.Fprintf(b, "  # %s\n", c)
+	}
+	if o.Description != "" {
+		d := o.Description
+		if len(d) > 100 {
+			d = d[:100] + "..."
+		}
+		fmt.Fprintf(b, "  # %s\n", d)
+	}
+	fmt.Fprintf(b, "  - name: %s\n    oid: %s\n    type: %s\n    unit: %s\n    interval: TODO\n", o.Name, oid, dm.typ, dm.unit)
+	if dm.scale != 0 {
+		fmt.Fprintf(b, "    scale: %s\n", strconv.FormatFloat(dm.scale, 'f', -1, 64))
+	}
+	if dm.label != "" {
+		fmt.Fprintf(b, "    index_label: { column: %s, as: %s }\n", dm.label, dm.labelAs)
+	}
+	if len(dm.enum) > 0 {
+		b.WriteString("    enum:\n")
+		keys := make([]int, 0, len(dm.enum))
+		for k := range dm.enum {
+			keys = append(keys, k)
+		}
+		sort.Ints(keys)
+		for _, k := range keys {
+			fmt.Fprintf(b, "      %d: %q\n", k, dm.enum[k])
+		}
+	}
+}

cmd/nmon/profile_probe.go

@@ -0,0 +1,97 @@
+package main
+
+import (
+	"context"
+	"errors"
+	"fmt"
+	"io"
+	"net/netip"
+	"time"
+
+	"github.com/v10networks/nmon/internal/config"
+	"github.com/v10networks/nmon/internal/profile"
+	"github.com/v10networks/nmon/internal/profiletest"
+	"github.com/v10networks/nmon/internal/snmp"
+)
+
+// resolveCredential normalises --version (v1, v2c, v3 or bare; default by
+// whether a v3 user was given) into cred.Version and checks the secrets that
+// version needs.
+func resolveCredential(version string, cred *snmp.Credential) error {
+	switch version {
+	case "":
+		version = "2c"
+		if cred.V3User != "" {
+			version = "3"
+		}
+	case "v1", "v2c", "v3":
+		version = version[1:]
+	}
+	cred.Version = version
+	switch {
+	case version != "1" && version != "2c" && version != "3":
+		return errors.New("--version must be v1, v2c or v3")
+	case version != "3" && cred.Community == "":
+		return fmt.Errorf("--community is required for SNMP v%s", version)
+	case version == "3" && cred.V3User == "":
+		return errors.New("--v3-user is required for SNMPv3")
+	}
+	return nil
+}
+
+// profileTest implements `nmon profile test`: discovery plus one poll of every
+// interval group with the matching profile, printing each metric.
+func profileTest(ctx context.Context, args []string, stdout io.Writer) error {
+	fs := profileFlagSet("test",
+		"profile test <ip> [--port N] [--version 1|2c|3] [--community C | --v3-user U ...] [--data-dir DIR]")
+	var (
+		port    int
+		version string
+		cred    snmp.Credential
+		dataDir string
+		timeout time.Duration
+	)
+	fs.IntVar(&port, "port", 161, "device UDP port")
+	fs.StringVar(&version, "version", "", "SNMP version: v1, v2c or v3 (default v3 when --v3-user is set, else v2c)")
+	fs.StringVar(&cred.Community, "community", "", "v1/v2c community")
+	fs.StringVar(&cred.V3User, "v3-user", "", "SNMPv3 user name")
+	fs.StringVar(&cred.V3AuthProto, "v3-auth-proto", "", "SNMPv3 auth protocol: MD5, SHA, SHA224, SHA256, SHA384, SHA512 (default SHA256)")
+	fs.StringVar(&cred.V3AuthPass, "v3-auth-pass", "", "SNMPv3 authentication passphrase")
+	fs.StringVar(&cred.V3PrivProto, "v3-priv-proto", "", "SNMPv3 privacy protocol: DES, AES, AES192, AES256 (default AES)")
+	fs.StringVar(&cred.V3PrivPass, "v3-priv-pass", "", "SNMPv3 privacy passphrase")
+	fs.StringVar(&cred.V3Context, "v3-context", "", "SNMPv3 context name")
+	fs.StringVar(&dataDir, "data-dir", "", "load operator profiles from <data-dir>/profiles over the shipped ones")
+	fs.DurationVar(&timeout, "timeout", 0, "per-request SNMP timeout (default 2s)")
+	pos, err := parseInterspersed(fs, args)
+	if err != nil {
+		return flagErr(err)
+	}
+	if len(pos) != 1 {
+		return fmt.Errorf("usage: nmon profile test <ip> [flags]")
+	}
+	ip, err := netip.ParseAddr(pos[0])
+	if err != nil {
+		return fmt.Errorf("bad address %q: %w", pos[0], err)
+	}
+	if err := resolveCredential(version, &cred); err != nil {
+		return err
+	}
+	dir := ""
+	if dataDir != "" {
+		dir = config.ProfilesDir(dataDir)
+	}
+	set, err := profile.Load(dir)
+	if err != nil {
+		return err
+	}
+	res, err := profiletest.Run(ctx, profiletest.Options{
+		Addr: netip.AddrPortFrom(ip, uint16(port)), Cred: cred, Profiles: set, Out: stdout, Timeout: timeout,
+	})
+	if err != nil {
+		return err
+	}
+	if res.Poll.Mismatches > 0 || res.Poll.WalkPDUs > 0 {
+		return fmt.Errorf("%d type mismatches, %d walk PDUs on the poll path", res.Poll.Mismatches, res.Poll.WalkPDUs)
+	}
+	return nil
+}

cmd/nmon/profile_record.go

@@ -0,0 +1,179 @@
+package main
+
+import (
+	"bytes"
+	"context"
+	"fmt"
+	"io"
+	"net/netip"
+	"os"
+	"time"
+
+	"github.com/gosnmp/gosnmp"
+
+	"github.com/v10networks/nmon/internal/fixturegen"
+	"github.com/v10networks/nmon/internal/simagent"
+	"github.com/v10networks/nmon/internal/snmp"
+)
+
+// defaultRecordSubtrees is what `profile record` walks when --subtree is not given:
+// system, interfaces, ifMIB, host, entity, entitySensor, UPS, printer and enterprises.
+var defaultRecordSubtrees = []string{
+	"1.3.6.1.2.1.1",  // system
+	"1.3.6.1.2.1.2",  // interfaces
+	"1.3.6.1.2.1.31", // ifMIB
+	"1.3.6.1.2.1.25", // host
+	"1.3.6.1.2.1.47", // entity
+	"1.3.6.1.2.1.99", // entitySensor
+	"1.3.6.1.2.1.33", // upsMIB
+	"1.3.6.1.2.1.43", // printmib
+	"1.3.6.1.4.1",    // enterprises
+}
+
+const redacted = "REDACTED"
+
+var redactedOIDs = map[string]bool{
+	"1.3.6.1.2.1.1.4.0": true, // sysContact
+	"1.3.6.1.2.1.1.6.0": true, // sysLocation
+}
+
+type recordOpts struct {
+	Target     snmp.Target
+	Subtrees   []string
+	MaxReps    int
+	MaxRecords int
+}
+
+func profileRecord(ctx context.Context, args []string, stdout io.Writer) error {
+	fs := profileFlagSet("record",
+		"profile record <ip> [--port N] [--community C | --version 3 --v3-user U ...] [--out FILE.snmprec] [--subtree OID]...")
+	var (
+		port       int
+		version    string
+		cred       snmp.Credential
+		out        string
+		subtrees   listFlag
+		timeout    time.Duration
+		maxReps    int
+		maxRecords int
+	)
+	fs.IntVar(&port, "port", 161, "device UDP port")
+	fs.StringVar(&version, "version", "", "SNMP version: 1, 2c or 3 (default 3 when --v3-user is set, else 2c)")
+	fs.StringVar(&cred.Community, "community", "", "v1/v2c community")
+	fs.StringVar(&cred.V3User, "v3-user", "", "SNMPv3 user name")
+	fs.StringVar(&cred.V3AuthProto, "v3-auth-proto", "", "SNMPv3 auth protocol: MD5, SHA, SHA224, SHA256, SHA384, SHA512 (default SHA256)")
+	fs.StringVar(&cred.V3AuthPass, "v3-auth-pass", "", "SNMPv3 authentication passphrase")
+	fs.StringVar(&cred.V3PrivProto, "v3-priv-proto", "", "SNMPv3 privacy protocol: DES, AES, AES192, AES256, AES192C, AES256C (default AES)")
+	fs.StringVar(&cred.V3PrivPass, "v3-priv-pass", "", "SNMPv3 privacy passphrase")
+	fs.StringVar(&cred.V3Context, "v3-context", "", "SNMPv3 context name")
+	fs.StringVar(&out, "out", "", "write the recording here instead of stdout")
+	fs.Var(&subtrees, "subtree",
+		"OID to walk; repeatable (default: system, interfaces, ifMIB, host, entity, entitySensor, ups, printer, enterprises)")
+	fs.DurationVar(&timeout, "timeout", 3*time.Second, "per-request timeout")
+	fs.IntVar(&maxReps, "max-repetitions", 25, "GETBULK max-repetitions")
+	fs.IntVar(&maxRecords, "max-records", 500000, "stop with an error after this many varbinds")
+	pos, err := parseInterspersed(fs, args)
+	if err != nil {
+		return flagErr(err)
+	}
+	if len(pos) != 1 {
+		return fmt.Errorf("usage: nmon profile record <ip> [flags]")
+	}
+	ip, err := netip.ParseAddr(pos[0])
+	if err != nil {
+		return fmt.Errorf("bad address %q: %w", pos[0], err)
+	}
+	switch {
+	case version != "":
+	case cred.V3User != "":
+		version = "3"
+	default:
+		version = "2c"
+	}
+	cred.Version = version
+	if version != "3" && cred.Community == "" {
+		return fmt.Errorf("--community is required for SNMP v%s", version)
+	}
+	if version == "3" && cred.V3User == "" {
+		return fmt.Errorf("--v3-user is required for SNMPv3")
+	}
+	if len(subtrees) == 0 {
+		subtrees = defaultRecordSubtrees
+	}
+	var buf bytes.Buffer
+	n, err := recordDevice(ctx, recordOpts{
+		Target:     snmp.Target{Addr: netip.AddrPortFrom(ip, uint16(port)), Cred: cred, Timeout: timeout},
+		Subtrees:   subtrees,
+		MaxReps:    maxReps,
+		MaxRecords: maxRecords,
+	}, &buf)
+	if err != nil {
+		return err
+	}
+	if out != "" {
+		if err := os.WriteFile(out, buf.Bytes(), 0o644); err != nil {
+			return err
+		}
+		fmt.Fprintf(os.Stderr, "recorded %d varbinds to %s\n", n, out)
+		return nil
+	}
+	_, err = stdout.Write(buf.Bytes())
+	return err
+}
+
+// recordDevice walks the subtrees read-only (GETBULK, or GETNEXT on v1) and writes
+// an snmprec recording to w with the community, sysContact and sysLocation redacted.
+// It returns the number of records written.
+func recordDevice(ctx context.Context, o recordOpts, w io.Writer) (int, error) {
+	s, err := snmp.Dial(ctx, o.Target, "discovery")
+	if err != nil {
+		return 0, err
+	}
+	defer func() { _ = s.Close() }() // read-only session
+	var recs []simagent.Record
+	for _, root := range o.Subtrees {
+		err := s.Walk(ctx, root, o.MaxReps, func(vb snmp.Varbind) error {
+			if vb.Exception() {
+				return nil
+			}
+			if len(recs) >= o.MaxRecords {
+				return fmt.Errorf("more than %d varbinds; narrow the walk with --subtree", o.MaxRecords)
+			}
+			recs = append(recs, redact(vb, o.Target.Cred.Community))
+			return nil
+		})
+		if err != nil {
+			return 0, fmt.Errorf("walk %s: %w", root, err)
+		}
+	}
+	rec := simagent.NewRecording(recs)
+	if rec.Len() == 0 {
+		return 0, fmt.Errorf("the device returned nothing under %v", o.Subtrees)
+	}
+	if err := fixturegen.WriteSnmprec(w, rec); err != nil {
+		return 0, err
+	}
+	return rec.Len(), nil
+}
+
+// redact turns a varbind into a recording row, replacing secrets with REDACTED.
+func redact(vb snmp.Varbind, community string) simagent.Record {
+	r := simagent.Record{OID: vb.OID, Type: vb.Type, Value: vb.Value}
+	if redactedOIDs[vb.OID] {
+		r.Type, r.Value = gosnmp.OctetString, []byte(redacted)
+		return r
+	}
+	if community != "" {
+		switch v := vb.Value.(type) {
+		case []byte:
+			if string(v) == community {
+				r.Value = []byte(redacted)
+			}
+		case string:
+			if vb.Type == gosnmp.OctetString && v == community {
+				r.Value = []byte(redacted)
+			}
+		}
+	}
+	return r
+}

cmd/nmon/profile_test.go

@@ -0,0 +1,224 @@
+package main
+
+import (
+	"bytes"
+	"context"
+	"net/netip"
+	"os"
+	"os/exec"
+	"path/filepath"
+	"strconv"
+	"strings"
+	"testing"
+	"time"
+
+	"github.com/v10networks/nmon/internal/profile"
+	"github.com/v10networks/nmon/internal/simagent"
+)
+
+func bundledMIBs(t *testing.T) string {
+	t.Helper()
+	d, _ := filepath.Abs(filepath.Join("..", "..", "mibs"))
+	if _, err := os.Stat(d); err != nil {
+		t.Skip("bundled MIBs not present")
+	}
+	return d
+}
+
+func fillTODOs(s string) string {
+	s = strings.ReplaceAll(s, "interval: TODO", "interval: 5m")
+	return strings.ReplaceAll(s, "unit: TODO", "unit: count")
+}
+
+func runNew(t *testing.T, args ...string) string {
+	t.Helper()
+	var out bytes.Buffer
+	if err := profileNew(context.Background(), args, &out); err != nil {
+		t.Fatal(err)
+	}
+	return out.String()
+}
+
+func TestProfileNewIFMIBTable(t *testing.T) {
+	d := runNew(t, "--mib", "IF-MIB", "--table", "ifXTable", "--mibs-dir", bundledMIBs(t))
+	if _, err := profile.Parse("draft-if-mib.yaml", []byte(d)); err == nil || !strings.Contains(err.Error(), "TODO") {
+		t.Fatalf("an unfilled draft must be rejected naming TODO, got %v", err)
+	}
+	p, err := profile.Parse("draft-if-mib.yaml", []byte(fillTODOs(d)))
+	if err != nil {
+		t.Fatalf("filled draft: %v\n%s", err, d)
+	}
+	byName := map[string]profile.Metric{}
+	for _, m := range p.Metrics {
+		byName[m.Name] = m
+	}
+	hc := byName["ifHCInOctets"]
+	if hc.OID != "1.3.6.1.2.1.31.1.1.1.6" || hc.Type != profile.Counter64 || hc.IndexLabel == nil || hc.IndexLabel.Column != "ifIndex" || hc.IndexLabel.As != "iface" {
+		t.Errorf("ifHCInOctets = %+v", hc)
+	}
+	if m := byName["ifLinkUpDownTrapEnable"]; m.Type != profile.Status || m.Enum[1] != "enabled" {
+		t.Errorf("ifLinkUpDownTrapEnable = %+v", m)
+	}
+	if m := byName["ifAlias"]; m.Type != profile.Text {
+		t.Errorf("ifAlias = %+v", m)
+	}
+	if !strings.Contains(d, "DISPLAY-HINT") {
+		t.Errorf("expected a DISPLAY-HINT comment:\n%s", d)
+	}
+}
+
+func TestProfileNewScalarsAndObjects(t *testing.T) {
+	d := runNew(t, "--mib", "SNMPv2-MIB", "--objects", "sysUpTime,sysName", "--mibs-dir", bundledMIBs(t))
+	p, err := profile.Parse("draft-snmpv2-mib.yaml", []byte(fillTODOs(d)))
+	if err != nil {
+		t.Fatalf("%v\n%s", err, d)
+	}
+	if len(p.Metrics) != 2 || p.Metrics[0].OID != "1.3.6.1.2.1.1.3.0" || p.Metrics[0].Unit != "seconds" {
+		t.Errorf("metrics = %+v", p.Metrics)
+	}
+}
+
+func TestProfileNewHintAndUnits(t *testing.T) {
+	d := runNew(t, "--mib", "TEST-MIB", "--mibs-dir", "../../internal/mib/testdata")
+	for _, want := range []string{"suggest scale: 0.1", "oid: 1.3.6.1.4.1.99999.1.1.0", "unit: celsius", "type: status", "2: \"on\"",
+		"index_label: { column: testName, as: component }"} {
+		if !strings.Contains(d, want) {
+			t.Errorf("missing %q in:\n%s", want, d)
+		}
+	}
+	if _, err := profile.Parse("draft-test-mib.yaml", []byte(fillTODOs(d))); err != nil {
+		t.Fatalf("%v\n%s", err, d)
+	}
+}
+
+func TestProfileNewErrors(t *testing.T) {
+	var out bytes.Buffer
+	for _, args := range [][]string{
+		{},
+		{"--mib", "NO-SUCH-MIB", "--mibs-dir", "../../internal/mib/testdata"},
+		{"--mib", "TEST-MIB", "--table", "nope", "--mibs-dir", "../../internal/mib/testdata"},
+		{"--mib", "TEST-MIB", "--objects", "testTable", "--mibs-dir", "../../internal/mib/testdata"},
+	} {
+		if err := profileNew(context.Background(), args, &out); err == nil {
+			t.Errorf("%v: expected an error", args)
+		}
+	}
+}
+
+const recordSample = `1.3.6.1.2.1.1.1.0|4|Test device
+1.3.6.1.2.1.1.2.0|6|1.3.6.1.4.1.8072.3.2.10
+1.3.6.1.2.1.1.3.0|67|123456
+1.3.6.1.2.1.1.4.0|4|admin@example.com
+1.3.6.1.2.1.1.5.0|4|secret-comm
+1.3.6.1.2.1.1.6.0|4|Rack 12, Building 3
+1.3.6.1.2.1.2.1.0|2|1
+1.3.6.1.2.1.2.2.1.1.1|2|1
+1.3.6.1.2.1.2.2.1.10.1|65|42
+1.3.6.1.2.1.31.1.1.1.6.1|70|18446744073709551615
+1.3.6.1.4.1.9999.1.1.0|4|secret-comm
+1.3.6.1.4.1.9999.1.2.0|4x|00ff
+1.3.6.1.4.1.9999.1.3.0|64|10.1.2.3
+`
+
+func TestProfileRecordRedacts(t *testing.T) {
+	rec, err := simagent.ParseRecording(strings.NewReader(recordSample))
+	if err != nil {
+		t.Fatal(err)
+	}
+	ctx, cancel := context.WithTimeout(context.Background(), 20*time.Second)
+	defer cancel()
+	ag, err := simagent.Start(ctx, simagent.Config{Recording: rec, Community: "secret-comm"})
+	if err != nil {
+		t.Fatal(err)
+	}
+	defer func() { _ = ag.Close() }() // test cleanup
+	addr := ag.Addr()
+	for _, ver := range []string{"2c", "1"} {
+		var out bytes.Buffer
+		err := profileRecordTo(ctx, &out, addr, ver)
+		if err != nil {
+			t.Fatalf("v%s: %v", ver, err)
+		}
+		s := out.String()
+		for _, secret := range []string{"secret-comm", "admin@example.com", "Rack 12"} {
+			if strings.Contains(s, secret) {
+				t.Errorf("v%s: recording leaks %q:\n%s", ver, secret, s)
+			}
+		}
+		if n := strings.Count(s, "REDACTED"); n != 4 {
+			t.Errorf("v%s: want 4 REDACTED values, got %d:\n%s", ver, n, s)
+		}
+		got, err := simagent.ParseRecording(strings.NewReader(s))
+		if err != nil {
+			t.Fatalf("v%s: output does not parse: %v", ver, err)
+		}
+		want := rec.Len()
+		if ver == "1" {
+			want-- // Counter64 does not exist in SNMPv1
+		}
+		if got.Len() != want {
+			t.Errorf("v%s: %d records, want %d\n%s", ver, got.Len(), want, s)
+		}
+	}
+}
+
+func profileRecordTo(ctx context.Context, out *bytes.Buffer, addr netip.AddrPort, ver string) error {
+	return profileRecord(ctx, []string{addr.Addr().String(), "--port", itoa(int(addr.Port())), "--community", "secret-comm",
+		"--version", ver, "--timeout", "1s", "--subtree", "1.3.6.1.2.1", "--subtree", "1.3.6.1.4.1"}, out)
+}
+
+func itoa(n int) string { return strconv.Itoa(n) }
+
+func TestProfileRecordArgs(t *testing.T) {
+	var out bytes.Buffer
+	for _, args := range [][]string{{}, {"10.0.0.1"}, {"nonsense", "--community", "x"}, {"10.0.0.1", "--version", "3"}} {
+		if err := profileRecord(context.Background(), args, &out); err == nil {
+			t.Errorf("%v: expected an error", args)
+		}
+	}
+}
+
+func TestProfileTestArgs(t *testing.T) {
+	var out bytes.Buffer
+	for _, args := range [][]string{{}, {"10.0.0.1"}, {"nonsense", "--community", "x"}, {"10.0.0.1", "--version", "v3"}, {"10.0.0.1", "--version", "v9", "--community", "x"}} {
+		if err := profileTest(context.Background(), args, &out); err == nil {
+			t.Errorf("%v: expected an error", args)
+		}
+	}
+}
+
+func TestProfileTestPrintsMetrics(t *testing.T) {
+	rec, err := simagent.LoadRecording("../../testdata/snmprec/juniper-junos.snmprec")
+	if err != nil {
+		t.Fatal(err)
+	}
+	a, err := simagent.Start(context.Background(), simagent.Config{Recording: rec, Community: "lab"})
+	if err != nil {
+		t.Fatal(err)
+	}
+	defer func() { _ = a.Close() }() // test cleanup
+	var out bytes.Buffer
+	err = profileTest(context.Background(), []string{a.Addr().Addr().String(), "--port", itoa(int(a.Addr().Port())), "--community", "lab"}, &out)
+	if err != nil {
+		t.Fatalf("%v\n%s", err, out.String())
+	}
+	for _, want := range []string{"profile      juniper-junos", "ifHCInOctets", "jnxOperatingCPU", "PDUs per cycle", "0 type mismatches"} {
+		if !strings.Contains(out.String(), want) {
+			t.Errorf("output lacks %q:\n%s", want, out.String())
+		}
+	}
+}
+
+// The LibreNMS importer is a separate offline tool (DEVIATIONS #9): nmon must not link it,
+// and neither may nmon pull in the code that reads LibreNMS definitions.
+func TestNmonDoesNotImportLibreNMS(t *testing.T) {
+	out, err := exec.Command("go", "list", "-deps", ".").CombinedOutput()
+	if err != nil {
+		t.Skipf("go list unavailable: %v\n%s", err, out)
+	}
+	for _, pkg := range strings.Fields(string(out)) {
+		if strings.Contains(pkg, "internal/librenms") || strings.Contains(pkg, "nmon-librenms-import") {
+			t.Errorf("cmd/nmon depends on %s", pkg)
+		}
+	}
+}

cmd/nmon/serve.go

@@ -2,12 +2,14 @@ package main
 
 import (
 	"context"
+	"errors"
 	"flag"
 	"fmt"
 	"log/slog"
 	"os"
 
 	"github.com/v10networks/nmon/internal/app"
+	"github.com/v10networks/nmon/internal/cliout"
 	"github.com/v10networks/nmon/internal/config"
 )
 
@@ -23,7 +25,9 @@ var hidden = map[string]bool{"poll-interval": true, "snmp-port": true}
 func newFlagSet(name, usage string) *flag.FlagSet {
 	fs := flag.NewFlagSet(name, flag.ContinueOnError)
 	fs.Usage = func() {
-		fmt.Fprintf(fs.Output(), "usage: nmon %s\n\nflags:\n", usage)
+		// Usage text is best-effort; a failed write to the terminal has nowhere to go.
+		out := cliout.New(fs.Output())
+		out.Printf("usage: nmon %s\n\nflags:\n", usage)
 		fs.VisitAll(func(f *flag.Flag) {
 			if hidden[f.Name] {
 				return
@@ -32,7 +36,7 @@ func newFlagSet(name, usage string) *flag.FlagSet {
 			if f.DefValue != "" && f.DefValue != "false" && f.DefValue != "0" {
 				def = fmt.Sprintf(" (default %s)", f.DefValue)
 			}
-			fmt.Fprintf(fs.Output(), "  --%s\n        %s%s\n", f.Name, f.Usage, def)
+			out.Printf("  --%s\n        %s%s\n", f.Name, f.Usage, def)
 		})
 	}
 	return fs
@@ -49,11 +53,15 @@ func serve(ctx context.Context, args []string) error {
 	var f config.Flags
 	fs := newFlagSet("serve", "serve --data-dir DIR --insecure-http [flags]")
 	storeFlags(fs, &f)
-	fs.StringVar(&f.SecretKeyFile, "secret-key-file", app.DefaultSecretKeyFile, "SNMP credential key file; created on first run; must be outside --data-dir")
+	fs.StringVar(&f.SecretKeyFile, "secret-key-file", app.DefaultSecretKeyFile,
+		"SNMP credential key file; created on first run; must be outside --data-dir")
 	fs.StringVar(&f.Listen, "listen", app.DefaultListen, "address for the API")
 	fs.BoolVar(&f.InsecureHTTP, "insecure-http", false, "serve plain HTTP with no authentication (required until TLS and auth arrive in M6)")
 	fs.StringVar(&f.VMHotURL, "vm-hot-url", "", "use this VictoriaMetrics instance as the hot store instead of the embedded one")
 	fs.StringVar(&f.VMLongURL, "vm-long-url", "", "use this VictoriaMetrics instance as the long store instead of the embedded one")
+	fs.StringVar(&f.TrapListen, "trap-listen", app.DefaultTrapListen,
+		"UDP address for SNMP traps; empty disables the receiver "+
+			"(port 162 needs CAP_NET_BIND_SERVICE; without it traps are off and polling continues)")
 	fs.IntVar(&f.MaxInflight, "max-inflight", 512, "most SNMP polls in flight at once")
 	fs.DurationVar(&f.PollInterval, "poll-interval", 0, "dev: SNMP poll interval (default 60s)")
 	fs.IntVar(&f.SNMPPort, "snmp-port", 0, "dev: UDP port of every device's agent (default 161)")
@@ -70,7 +78,7 @@ func serve(ctx context.Context, args []string) error {
 
 // flagErr turns flag.ErrHelp into a clean exit.
 func flagErr(err error) error {
-	if err == flag.ErrHelp {
+	if errors.Is(err, flag.ErrHelp) {
 		os.Exit(0)
 	}
 	return err

docs/DEVIATIONS.md

@@ -14,3 +14,10 @@ conscious, reviewed exception.
 | 7 | `import-librenms` reads `includes/definitions/*.yaml` and `includes/definitions/discovery/*.yaml` | Reads `resources/definitions/os_detection/*.yaml` and `resources/definitions/os_discovery/*.yaml`, with the old paths as a fallback. | LibreNMS moved them; the spec's paths no longer exist upstream. | M2 |
 | 8 | Real recordings replace synthetic fixtures when available | LibreNMS's `tests/snmpsim/*.snmprec` (2,054 real device recordings) are used by optional tests when `NMON_LIBRENMS_DIR` points at a checkout. They are never copied into this repo. | Real-device coverage without vendoring GPL test data into an Apache-2.0 repo. | M2 |
 | 9 | `nmon profile import-librenms <repo-path>` is an nmon subcommand | A separate binary, `nmon-librenms-import` (`cmd/nmon-librenms-import`), run offline before nmon. It writes draft profiles that the operator reviews and copies into `<data-dir>/profiles/`. `nmon` neither links nor exposes it. | User decision (2026-10-22). It keeps the importer out of the product binary and makes "the converter never runs at serve time" structural. | M2 |
+| 10 | `scripts/openapi-diff` fails on an incompatible change (M3 milestone) | The differ is the Go package `internal/openapidiff` (unit-tested, run with `go run ./internal/openapidiff/cmd/openapidiff`), driven by `scripts/openapi-check.sh`, which `make gate-m3` and the CI `openapi` job call. | A Go package is testable and linted like the rest of the code; the script only fetches the spec at the last `m*`/`v*` tag. No new dependency. | M3 |
+| 11 | Built assets are embedded from `web/dist` into `internal/webui` | `make web` copies `web/dist` to `internal/webui/dist` (git-ignored, `.gitkeep` tracked); a committed `internal/webui/placeholder/index.html` ("UI not built") is served when `dist` has no `index.html`. | A tracked `dist/index.html` would be overwritten by every build and dirty the tree, and a built UI must never be committed. `go build` still works without node. | M3 |
+| 12 | (not specified) | Developer tools (`backfill`, `seed-demo`) are a separate executable, `cmd/nmon-devtools` (`make devtools` builds `nmon-devtools`), never shipped. It talks to a running nmon over its HTTP API and to the hot store via `--hot-url`. `nmon` has no `devtools` command; a depguard rule keeps `cmd/nmon` from importing `internal/simagent` or `internal/fixturegen` beyond `profile_record.go`, which already used them for `nmon profile record` in M2. | The gate needs 30 days of history without waiting 30 days, and live screenshots need a simulated network. See `docs/dev.md`. | M3 |
+| 13 | (not specified) `/docs` API reference | `/docs` serves a vendored, pinned swagger-ui-dist 5.17.14 (Apache-2.0, about 1.6 MB) through `embed.FS`. | huma's built-in renderers load their assets from a CDN, which an offline monitor cannot rely on. | M3 |
+| 14 | M2 defined provisional `poller/health` and `identity-reviews` responses | Both were reshaped in M3 to the reviewed UI contract, before any `openapi.json` existed, so the route freeze starts at `m3`, the first tag with a checked-in spec. | The M2 shapes had no consumer. `scripts/openapi-check.sh` passes against `m2` with a note and diffs for real from `m3`. | M3 |
+| 15 | A single-signal failure (ICMP only or SNMP only) is a warning | The warning is held as pending for 5 min before it notifies, and is closed silently if the device goes down meanwhile. | Otherwise a real outage whose second signal fails seconds later sends a spurious warning first. | M4 |
+| 16 | An unsupported probe is unknown, never failed | When ICMP is unsupported (host can't open unprivileged ICMP, or per device), SNMP alone decides down, as with `icmp_blocked`, and a one-time `icmp_unsupported` device warning is raised. | Otherwise nmon could never declare a device down on such a host, and nobody would notice. | M4 |

docs/MAINTAINABILITY.md

@@ -0,0 +1,47 @@
+# Maintainability standard
+
+**This is a hard rule** (owner decision, 2026-10-22). Code that breaks it does not merge, and a milestone with findings is not tagged. The machine enforces it: `make lint` runs golangci-lint with `.golangci.yml` (Go) and ESLint (web). Every `scripts/gate-m*.sh` runs `make lint` first, and so does CI.
+
+## Limits (production code)
+
+| What | Limit | Enforced by |
+|---|---|---|
+| Function length | 80 lines, 50 statements | `funlen` |
+| Cyclomatic complexity | 15 per function | `cyclop` |
+| Cognitive complexity | 20 per function | `gocognit` |
+| Nesting | `if` depth 4 | `nestif` |
+| Duplicated blocks | 150 tokens | `dupl` |
+| Line length | 140 characters | `lll` |
+| File length | 600 lines (split by concern before that) | `scripts/lint-filesize.sh` |
+| Unused code, dead fields | none | `unused` |
+| Deprecated APIs | none | `staticcheck` |
+| Unchecked errors | none | `errcheck`, `errorlint` |
+| Magic HTTP status numbers | none (use `http.Status*`) | `usestdlibvars` |
+
+Tests (`_test.go`) are exempt from the length and complexity limits, because table-driven tests are long by nature. They must still pass every other linter.
+
+## Architecture rules (enforced by `depguard` and `forbidigo`)
+
+- **SQL and the ORM live only in `internal/store`.** No other package imports `github.com/uptrace/bun` or `database/sql`.
+- **Layering:** `cmd → app → {api, poller, discovery, traps, alert, notify, …} → {store, snmp, profile, metrics, clock, …}`.
+  - Only `cmd/*` imports `internal/app`.
+  - Only `internal/app` (and tests) imports `internal/api`.
+  - Collection paths do not import each other: `poller`, `discovery`, `traps`, `ingest`, `checks`, `rollup` and `alert` share code through a lower package such as `internal/snmpx`, not through each other.
+  - `cmd/nmon` never imports `internal/librenms` (the importer is a separate tool).
+- **Time comes from `internal/clock`.** `time.Now`, `time.Sleep`, `time.After`, `time.Tick` and `time.NewTicker` are forbidden outside `internal/clock`, `cmd/` and tests.
+- **No global mutable state** except the `selfmon.Default` registry and package-level caches that are documented as such.
+
+## Habits the linters can't check (reviewers enforce these)
+
+- One concern per file. Name files after what they hold (`matcher.go`, not `util.go`). No `util`, `helpers` or `common` packages.
+- Split a long function into named steps that read like the spec (`collect → match → apply → audit`), not into `doPart1/doPart2`.
+- Errors are wrapped with context (`fmt.Errorf("discovery %s: %w", slug, err)`) and handled once.
+- Every exported identifier has a doc comment that says *why* or *what contract*, not a restatement of the name.
+- Comments explain decisions, not mechanics. A decision that departs from the spec goes in `docs/DEVIATIONS.md`.
+- Tests are named for the behaviour they lock in (`TestStackSwapOpensOneReviewAndNeverMerges`).
+- `//nolint` is allowed only with the linter named and a reason (`//nolint:funlen // generated table`). `nolintlint` enforces this.
+- New dependencies need a line in `docs/DEVIATIONS.md` row 3 saying why the standard library isn't enough.
+
+## Web (`web/`)
+
+ESLint with typescript-eslint (strict), `max-lines-per-function` 80, `complexity` 15, `max-depth` 4, `max-lines` 400 per file, no `any`, react-hooks rules. `TrafficGraph.tsx` is the only file that imports uPlot. API types are only generated, never hand-written.

docs/dev.md

@@ -0,0 +1,50 @@
+# Developer notes
+
+## Building the UI into the binary
+
+`make build` runs `make web` first: `npm run build` in `web/`, then `web/dist` is copied to
+`internal/webui/dist`, which `//go:embed` packs into the binary. `internal/webui/dist` is git-ignored
+(only `.gitkeep` is tracked), so a build never dirties the tree. A plain `go build` without `make web`
+embeds a one-line "UI not built" page from `internal/webui/placeholder/`.
+
+nmon serves the UI at `/`. Unknown paths fall back to `index.html` for the client-side router, except
+`/api/`, `/docs`, `/openapi*`, `/metrics` and `/schemas`, which belong to the API. Files under `/assets/`
+are content-hashed and sent `immutable`; `index.html` is `no-cache`; text assets are served gzipped.
+
+## OpenAPI compatibility
+
+`scripts/openapi-check.sh` compares the current spec (`nmon openapi`, else `openapi.json`) with
+`openapi.json` at the latest `m*`/`v*` tag and fails on a removed route or method, a removed response
+field, a changed field type, a new required parameter or request field, or a removed enum value. A tag
+without `openapi.json` passes with a note. `OPENAPI_NEW=file.json` compares that file instead and
+`OPENAPI_BASE_TAG=m3` picks the base. The comparison is `internal/openapidiff`.
+
+## `nmon-devtools` (separate dev binary)
+
+Developer helpers in their own executable, `make devtools` -> `nmon-devtools`; the shipped `nmon` does not contain them and never links the simulator. They need a running `nmon serve --insecure-http`.
+
+**backfill** writes synthetic history straight into the hot store so graphs have 30 days of data without
+waiting 30 days:
+
+    nmon-devtools backfill --hot-url http://127.0.0.1:PORT --device SLUG --iface ULID [--iface ULID...] \
+        [--days 31] [--step 60s] [--pattern diurnal|flat] [--mean-mbps N]
+
+Per interface it writes `ifHCInOctets`, `ifHCOutOctets` (monotonic, diurnal rate with noise and bursts) and
+`ifOperStatus`, ending one step before the first live sample. When live samples exist the history is shifted
+so its last value joins the live counter with no reset (this needs a live counter larger than the history,
+about 3e13 bytes for 31 days at 100 Mbit/s; otherwise a warning says the join will look like a reset).
+The hot URL is in the serve log (`metric stores up hot=...`). Samples older than hot retention are dropped
+by the store.
+
+**seed-demo** builds a small simulated network and back-fills it, for the gate and for screenshots:
+
+    nmon serve --data-dir D --insecure-http --poll-interval 10s  ...
+    nmon-devtools seed-demo --api http://127.0.0.1:8443 --hot-url http://127.0.0.1:PORT \
+        [--env-out env] [--counters-rec testdata/snmprec/counters.snmprec]
+
+It starts the simulated SNMP agents in-process on `[::1]`, each on its own port (passed to the API as `snmp.port`), adds the devices through the API (a 48-port switch, access switches, routers, a firewall, a UPS, the counters fixture, a v1 device with 32-bit counters, and one whose agent is stopped after seeding so it reads as down), waits for live polls, back-fills 31 days, writes `NMON_DEVICE`, `NMON_DEVICE_48`, `NMON_DEVICE_32BIT` and `NMON_DEVICE_DOWN` to `--env-out`, and keeps the agents answering until interrupted. The simulated 64-bit counters start at 1e14 so history fits below them.
+
+## Gates
+
+`make gate-m3` runs everything above end to end and writes live screenshots to `docs/screenshots/M3/`.
+It needs Playwright's chromium: `cd web && npx playwright install chromium`.

docs/milestones/M2-discovery-and-profiles.md

@@ -61,4 +61,25 @@ Adversarial: stack-member swap; RMA; GRE tunnel on Juniper; 32-bit wrap at 10G m
 
 ## Gate log
 
-_(filled in by the supervisor when the gate passes)_
+**Passed 2026-10-22**, run by the supervisor (Opus) on linux/amd64.
+
+| Check | Result |
+|---|---|
+| `make lint` (golangci-lint v2.14.0 + file sizes + ESLint) | **0 findings** (the maintainability hard rule took effect during M2: about 450 findings cleared, 3 justified `nolint`s for long OpenAPI doc tags) |
+| `go test -race ./...` and `-tags 'integration vmembed'` | all ok |
+| `./scripts/test-pg.sh` | ok (Postgres 16) |
+| Flaky-test proof | `go test -race -count=20 -run 'Concurrency\|Degraded\|Slow\|GlobalInflight' ./internal/poller/` ok |
+| `make gate-m1` | PASS (lint included) |
+| `make gate-m2` | PASS: 25 fixtures over IPv6 and IPv4 (13 profiles + behaviour fixtures), exact PDU budgets, 0 walk PDUs on the poll path; v1 (GETNEXT) and v3 authPriv via `nmon profile test` |
+| Real devices (`NMON_LIBRENMS_DIR`) | 12 LibreNMS recordings: every one matched the right profile, 0 type mismatches |
+
+**Notable decisions in M2**
+- MIBs are a sidecar, not embedded (DEVIATIONS 6). The LibreNMS importer is a separate offline tool (DEVIATIONS 9).
+- Identity: ambiguous matches open a review and freeze the candidates until an admin resolves it. Clean matches are audited only when something changed.
+- Polling: backoff and degraded start after 3 consecutive failed cycles. Lower interval groups are skipped while the hot group fails.
+- Text metrics are never polled; they are discovery label sources only.
+- A production timing race in the poller (a timer registered after the clock moved woke a full interval late) was found by the flaky-test investigation and fixed (`timerUntil`).
+
+**Bugs found by real-device testing and fixed:** apc-ups UPS-MIB label columns were not-accessible, and text metrics were polled as scalars. The fixture generator now refuses to emit not-accessible columns.
+
+**Carried forward:** identity-review resolve/merge endpoint (M3 API); `profile` `max_varbinds` key (deferred; poller option exists); a facets endpoint for the UI (M3).

docs/milestones/M3-graphs-and-ui.md

@@ -33,4 +33,36 @@ API and UI: openapi.json generated with the TS client and the incompatible-diff
 
 ## Gate log
 
-_(filled in by the supervisor when the gate passes)_
+**Passed 2026-10-22**, run by the supervisor (Opus).
+
+| Check | Result |
+|---|---|
+| `make lint` (Go + web) | 0 findings |
+| `go test -race ./...`, `-tags 'integration vmembed'`, `test-pg.sh` | all ok |
+| `make gate-m1`, `make gate-m2` (with LibreNMS recordings) | PASS |
+| `make gate-m3` | PASS: UI embedded in the static binary; SPA fallback and cache headers; 10 simulated devices (`nmon-devtools seed-demo`) with 31 days of back-filled history; port graph renders in and out at 1 h, 24 h, 30 d; 48-port page < 2 s; openapi-check; web client regenerated from the live spec type-checks |
+| UI ↔ API contract | `TestGeneratedSpecMatchesUIContract`: the generated `openapi.json` is compatible with the contract the UI was built against |
+| Screenshots | `docs/screenshots/M3/` (real data, 18 files) and `docs/screenshots/M3-mock/` (mock data); reviewed by the supervisor and sent to the owner |
+
+**Decisions in M3:** dev tooling is a separate `nmon-devtools` binary (owner's call), never shipped. `/docs` uses vendored Swagger UI. The two M2 provisional routes were reshaped before the route freeze, which starts at `m3`, the first tag with `openapi.json`. Graph stitching joins at now − hot retention; p95 is computed live until M5 materialises it.
+
+**Carried forward:** a demo device that is genuinely Down needs an unreachable address; that comes with M4's reachability work (`device-unresponsive.png` shows Warning/degraded for now, which is correct per policy because ICMP still answers). `nmon profile record` still links the simulator package; to be moved to a shared `internal/snmprec` format package.
+
+## API contract for M3 (written before the WPs so the UI and API are built in parallel)
+
+All JSON. Timestamps are RFC 3339 UTC. Lists use `?page=1&per_page=100` (max 1,000) and return `{items: [...], page, per_page, total}`. Errors are RFC 9457 `application/problem+json`. Existing M1/M2 shapes (`InterfaceView`, `DeviceView`, the `SNMPBody` input) are extended, never renamed.
+
+| Route | Response |
+|---|---|
+| `GET /api/v1/devices?site=&role=&kind=&q=&state=&page=&per_page=` | `items: DeviceSummary[]`, where `DeviceSummary{slug, name, kind, site, role, mgmt_ip, profile, reachability: up\|down\|warning\|unknown\|maintenance, poll_state: ok\|degraded\|backoff, last_seen, interfaces_total, interfaces_down, warnings[]}` |
+| `GET /api/v1/devices/{slug}` | `DeviceView` (existing) plus `parents[{slug,name}]`, `groups[{id,name,kind}]`, `sys_descr`, `sys_object_id`, `hw_serial`, `uptime_seconds`, `reachability`, `poll_state`, `warnings[]`, `interfaces: InterfaceView[]` with added `unreliable`, `retired_at`, and live fields `in_bps`, `out_bps`, `in_errors_ps`, `out_errors_ps` (5 min rate, null when unknown or unreliable) |
+| `PUT /api/v1/devices/{slug}` | body: `{name?, site?, role?, enabled?, parents?: [slug], snmp?: SNMPBody}`; returns `DeviceView` |
+| `GET /api/v1/interfaces?q=&page=` | `items: InterfaceHit[]`, where `InterfaceHit{id, device{slug,name}, ifname, ifalias, ifdescr, oper_status, admin_status, speed_bps, in_bps, out_bps}` (q matches ifname and ifalias, case-insensitive) |
+| `GET /api/v1/graph?iface=&from=&to=&step=` | `{iface{id,ifname,ifalias,speed_bps,device{slug,name}}, step_seconds, tier: raw\|1h, stitched_at?: ts, partial: [{from,to}], unreliable: bool, series: {in: [[unix_s, bps\|null]...], out: [...], in_max?: [...], out_max?: [...]}, p95?: {in_bps, out_bps, source: materialised\|live, coverage}}`. Both directions come in one call. `dir=` is optional and filters to one direction. An `unreliable` interface returns empty series and `unreliable_reason` (e.g. `counter_32bit_fast_link`). A stitched response also carries `tiers: [{from, to, tier, step_seconds}]`; the top-level `step_seconds` is the step of the newest tier. |
+| `GET /api/v1/poller/health` | `{devices: [{slug, name, state, varbinds, interval_s, base_interval_s, last_cycle_s, missed_deadlines, consecutive_failures, last_error, next_cycle}], totals: {pdus_per_min, timeouts_per_min, deadline_misses_per_min, write_queue_depth, write_queue_capacity, devices_degraded}}`. Sortable client-side. |
+| `GET /api/v1/identity-reviews?page=` and `POST /api/v1/identity-reviews/{id}/resolve` | review list with candidates and evidence; resolve body `{action: merge\|keep_both, keep?: iface_id}` |
+| `GET /api/v1/query`, `GET /api/v1/query_range` | (existing) |
+| `GET /api/v1/devices/facets` | `{sites: string[], roles: string[], kinds: string[]}`: distinct values over non-retired devices, for the filter dropdowns |
+| `GET /api/v1/meta` | `{version, build, retention{hot,fiveminute,long} (Go duration strings, e.g. "720h0m0s"), now}` for the UI footer and the range picker |
+
+**Graph tiers:** for a range ≤ hot retention, raw data from hot with step = max(60 s, range/1000). For longer ranges, hot raw data where it exists stitched with `nmon_if_rate_bps_avg_1h`/`max_1h` from long before that point; `stitched_at` is the join timestamp. Until M5's rollup exists, long has no data, so the response carries `partial` for the uncovered span. That is honest, not an error.

docs/milestones/README.md

@@ -4,6 +4,7 @@ The build follows the six gated milestones in [`docs/spec/spec.md`](../spec/spec
 Each milestone has its own document here. It is written before any code for that milestone and
 its **Gate log** is filled in when the gate passes. A milestone is done only when:
 
+0. `make lint` is clean: maintainability is a hard rule ([`docs/MAINTAINABILITY.md`](../MAINTAINABILITY.md)), and every gate script runs lint first,
 1. every acceptance line it closes (from [`build-detail.md`](../spec/build-detail.md#acceptance-criteria)) has a test that passes,
 2. `make test` (`go test -race ./...`) and `make test-integration` pass,
 3. its gate command (`make gate-mN`) passes when run by the supervisor, and
@@ -12,9 +13,9 @@ its **Gate log** is filled in when the gate passes. A milestone is done only whe
 | # | Milestone | Gate | Doc | Status |
 |---|---|---|---|---|
 | M1 | Skeleton and fixtures | `nmon serve` polls the counters fixture and `/api/v1/query` returns rising ifHCInOctets | [M1](M1-skeleton-and-fixtures.md) | **passed**, tagged `m1` |
-| M2 | Discovery and profiles | every fixture's expect.yaml passes, including v1 and v3, and the PDU budget holds | [M2](M2-discovery-and-profiles.md) | in progress (WP1 done) |
-| M3 | Graphs and UI | a port's in/out graph renders at 1 h, 24 h and 30 d from the counters fixture | [M3](M3-graphs-and-ui.md) | planned |
-| M4 | Alerting | stopping a parent fixture sends one notification naming it and its children | [M4](M4-alerting.md) | planned |
+| M2 | Discovery and profiles | every fixture's expect.yaml passes, including v1 and v3, and the PDU budget holds | [M2](M2-discovery-and-profiles.md) | **passed**, tagged `m2` |
+| M3 | Graphs and UI | a port's in/out graph renders at 1 h, 24 h and 30 d from the counters fixture | [M3](M3-graphs-and-ui.md) | **passed**, tagged `m3` |
+| M4 | Alerting | stopping a parent fixture sends one notification naming it and its children | [M4](M4-alerting.md) | in progress (WP1 reach and deps, WP2 rules, WP3 notify done) |
 | M5 | Push ingest, rollup, checks | a replayed Proxmox sample shows under its node and a 2 y query hits the 1 h tier | [M5](M5-ingest-rollup-checks.md) | planned |
 | M6 | Auth and ops | a viewer gets 403 on PUT and the 2,000-device loadtest cycle finishes under 40 s | [M6](M6-auth-and-ops.md) | planned |
 | M7 | gNMI streaming | after v1; not built in this run | — | out of scope |
@@ -31,6 +32,8 @@ Departures from the spec are recorded in [`docs/DEVIATIONS.md`](../DEVIATIONS.md
 
 ## Rules every WP follows (from "Decisions that don't move")
 
+- **Maintainability is a hard rule.** Follow [`docs/MAINTAINABILITY.md`](../MAINTAINABILITY.md): zero golangci-lint and ESLint findings in your packages, the function, complexity and file-size limits, and the layering rules. Every WP brief cites it.
+
 - One static binary, `CGO_ENABLED=0`. No raw SQL outside `internal/store`.
 - The 60 s poll path talks only to devices (SNMP, ICMP) and the local hot store.
 - Metric labels on SNMP series: `device=<slug>`, plus `iface=<ULID>` on interface series. Nothing else.
@@ -39,3 +42,11 @@ Departures from the spec are recorded in [`docs/DEVIATIONS.md`](../DEVIATIONS.md
 - IPv6 first: every network path works on v6 and v4; tests default to `::1`.
 - Time comes from `internal/clock`. No `time.Now()`/`time.Sleep` in logic that a test must control.
 - Tests never need real hardware. Fixtures are `.snmprec` files served by `internal/simagent`.
+
+## Deferred (revisit after v1 milestones)
+
+- **Deployment playbook**: install layout (binary, `/usr/share/nmon/mibs` sidecar, systemd unit granting port 162, key file location), TLS/ACME or proxy setup, IdP configuration, backups, and upgrades. Raised by the user on 2026-10-22; deliberately postponed.
+
+## Review artifacts
+
+- From M3 on, each UI milestone's gate captures Playwright screenshots of every page into `docs/screenshots/<milestone>/` for the user to review.

internal/alert/deliver.go

@@ -0,0 +1,92 @@
+package alert
+
+import (
+	"context"
+	"time"
+
+	"github.com/v10networks/nmon/internal/store"
+)
+
+// deliver sends the row's pending notification if it is still valid and not
+// suppressed. Suppressed notifications are held and sent when the suppression
+// ends, if still valid; acked rows drop everything except a resolution.
+func (ev *Evaluator) deliver(ctx context.Context, now time.Time, a *store.Alert, ent Entity) {
+	if ev.held(ctx, a, ent) {
+		return
+	}
+	p := a.NotifyPending
+	if p == "" {
+		return
+	}
+	acked := a.AckUntil != nil && now.Before(*a.AckUntil)
+	if !pendingValid(a, p) || (acked && p != NotifyResolved) {
+		a.NotifyPending = ""
+		ev.save(ctx, a)
+		return
+	}
+	if err := ev.o.Notifier.Notify(ctx, transitionOf(a, p)); err != nil {
+		ev.reg.Counter("nmon_alert_notify_errors_total", "rule", a.Rule).Inc()
+		ev.log.Warn("notify failed, will retry", "rule", a.Rule, "key", a.SeriesKey, "state", p, "err", err)
+		return
+	}
+	a.NotifyPending = ""
+	if p != NotifyStale {
+		a.NotifiedState = p
+	}
+	ev.save(ctx, a)
+}
+
+// held records the suppression reason on an active row and reports whether the
+// pending notification must wait for the suppression to end.
+func (ev *Evaluator) held(ctx context.Context, a *store.Alert, ent Entity) bool {
+	sup, why := ev.suppressed(ent)
+	if !isActive(a.State) {
+		return sup && a.NotifyPending != ""
+	}
+	reason := ""
+	if sup {
+		reason = why
+		if reason == "" {
+			reason = "suppressed"
+		}
+	}
+	if reason != a.SuppressedBy {
+		a.SuppressedBy = reason
+		ev.save(ctx, a)
+	}
+	return reason != "" && a.NotifyPending != ""
+}
+
+// pendingValid reports whether notification p still describes the row.
+func pendingValid(a *store.Alert, p string) bool {
+	switch p {
+	case NotifyFiring:
+		return a.BaseState == store.AlertFiring && a.State != store.AlertFlapping
+	case NotifyResolved:
+		return a.State == store.AlertResolved && (a.NotifiedState == NotifyFiring || a.NotifiedState == NotifyFlapping)
+	case NotifyStale:
+		return a.State == store.AlertStale && a.PriorState == store.AlertFiring && a.NotifiedState == NotifyFiring
+	case NotifyFlapping:
+		return a.State == store.AlertFlapping
+	}
+	return false
+}
+
+func transitionOf(a *store.Alert, state string) Transition {
+	t := Transition{
+		AlertID: a.ID, Rule: a.Rule, State: state, Severity: a.Severity, Device: a.DeviceSlug, Iface: a.Iface,
+		Component: a.Component, Value: a.Value, Threshold: a.Threshold, ClearedAt: a.ClearedAt,
+		Summary: a.Summary, Description: a.Description,
+	}
+	if a.FiredAt != nil {
+		t.FiredAt = *a.FiredAt
+	}
+	return t
+}
+
+func (ev *Evaluator) suppressed(ent Entity) (bool, string) {
+	if ev.o.Suppressed == nil {
+		return false, ""
+	}
+	return ev.o.Suppressed(ent)
+}

internal/alert/evaluator.go

@@ -0,0 +1,265 @@
+package alert
+
+import (
+	"context"
+	"errors"
+	"fmt"
+	"log/slog"
+	"sort"
+	"sync"
+	"time"
+
+	"github.com/v10networks/nmon/internal/clock"
+	"github.com/v10networks/nmon/internal/selfmon"
+	"github.com/v10networks/nmon/internal/store"
+)
+
+// Timing of the state machine.
+const (
+	// DefaultInterval is the evaluation period.
+	DefaultInterval = 30 * time.Second
+	// StaleAfter is how many consecutive evaluations without a series make it stale.
+	StaleAfter = 2
+	// FlapWindow and FlapMax: more than FlapMax state changes within
+	// FlapWindow put the entity into flapping for FlapHold.
+	FlapWindow = 10 * time.Minute
+	FlapMax    = 5
+	FlapHold   = 15 * time.Minute
+
+	queryTimeout = 25 * time.Second
+	// StoreHot is the name of the store rules run against.
+	StoreHot = "hot"
+)
+
+// Notification states handed to the Notifier.
+const (
+	NotifyFiring   = "firing"
+	NotifyResolved = "resolved"
+	NotifyStale    = "stale"
+	NotifyFlapping = "flapping"
+)
+
+// Entity identifies one alerting series: a rule on a device, optionally an
+// interface or a component of it.
+type Entity struct {
+	Rule, Device, Iface, Component string
+}
+
+// Key is the persisted series key.
+func (e Entity) Key() string { return e.Rule + "|" + e.Device + "|" + e.Iface + "|" + e.Component }
+
+// Transition is one notification the evaluator wants delivered. The incident ID
+// is "<AlertID>-<FiredAt unix>" (notify.IncidentID); a new firing after a
+// resolution has a new AlertID.
+type Transition struct {
+	AlertID                  int64
+	Rule, State, Severity    string
+	Device, Iface, Component string
+	Value, Threshold         float64
+	FiredAt                  time.Time
+	ClearedAt                *time.Time
+	Summary, Description     string
+}
+
+// Notifier receives transitions. A non-nil error means "not delivered"; the
+// evaluator retries on its next cycle. The app adapts it to notify.Queue.
+type Notifier interface {
+	Notify(ctx context.Context, t Transition) error
+}
+
+// Querier is the part of vmsup.Querier the evaluator uses.
+type Querier interface {
+	Query(ctx context.Context, store, q string, ts time.Time) ([]byte, error)
+}
+
+// Options configures an Evaluator. Store, Querier, Notifier, Clock and Rules
+// are required.
+type Options struct {
+	Store    store.Alerts
+	Querier  Querier
+	Notifier Notifier
+	Clock    clock.Clock
+	Rules    []Rule
+
+	// Groups answers group membership for Rule.Overrides. Optional.
+	Groups GroupLookup
+	// ThresholdFor supplies a per-device (per-profile) threshold for a rule;
+	// ok false falls through to the rule default. Group overrides beat it.
+	ThresholdFor func(device, rule string) (threshold float64, ok bool)
+	// Unreliable reports an interface whose counters cannot be trusted
+	// (32-bit counters on fast links); rules with SkipUnreliable ignore it.
+	Unreliable func(iface string) bool
+	// Active reports whether an entity still exists (device and interface not
+	// retired). Inactive entities are closed as retired, silently.
+	Active func(Entity) bool
+	// Suppressed reports a maintenance window or dependency suppression for
+	// an entity. A suppressed alert still changes state but is not notified.
+	Suppressed func(Entity) (bool, string)
+	// StoreHealth is told after every query whether the store answered.
+	StoreHealth func(ok bool, err error)
+
+	Interval  time.Duration // default DefaultInterval
+	StoreName string        // default StoreHot
+	Metrics   *selfmon.Registry
+	Logger    *slog.Logger
+}
+
+// Evaluator runs the rules and owns the persisted state machine.
+type Evaluator struct {
+	o     Options
+	rules []*compiledRule
+	log   *slog.Logger
+	reg   *selfmon.Registry
+
+	mu sync.Mutex
+}
+
+// New validates the rules and returns an Evaluator.
+func New(o Options) (*Evaluator, error) {
+	if o.Store == nil || o.Querier == nil || o.Notifier == nil || o.Clock == nil {
+		return nil, errors.New("alert: Store, Querier, Notifier and Clock are required")
+	}
+	if o.Interval <= 0 {
+		o.Interval = DefaultInterval
+	}
+	if o.StoreName == "" {
+		o.StoreName = StoreHot
+	}
+	if o.Logger == nil {
+		o.Logger = slog.Default()
+	}
+	if o.Metrics == nil {
+		o.Metrics = selfmon.Default
+	}
+	ev := &Evaluator{o: o, log: o.Logger.With("component", "alert"), reg: o.Metrics}
+	seen := map[string]bool{}
+	for _, r := range o.Rules {
+		if seen[r.Name] {
+			return nil, fmt.Errorf("alert: duplicate rule %q", r.Name)
+		}
+		seen[r.Name] = true
+		if r.Disabled {
+			continue
+		}
+		c, err := compile(r)
+		if err != nil {
+			return nil, err
+		}
+		ev.rules = append(ev.rules, c)
+		ev.reg.Counter("nmon_alert_eval_errors_total", "rule", r.Name) // visible at 0
+	}
+	return ev, nil
+}
+
+// Run evaluates once now and then every Interval until ctx ends.
+func (ev *Evaluator) Run(ctx context.Context) error {
+	t := ev.o.Clock.NewTicker(ev.o.Interval)
+	defer t.Stop()
+	for {
+		ev.EvalOnce(ctx)
+		select {
+		case <-ctx.Done():
+			return ctx.Err()
+		case <-t.C():
+		}
+	}
+}
+
+type reading struct {
+	ent   Entity
+	value float64
+}
+
+// EvalOnce runs one evaluation cycle at the clock's current time.
+func (ev *Evaluator) EvalOnce(ctx context.Context) {
+	ev.mu.Lock()
+	defer ev.mu.Unlock()
+	now := ev.o.Clock.Now().UTC()
+
+	rows, err := ev.o.Store.ListActiveAlertStates(ctx)
+	if err != nil {
+		ev.log.Error("load alert state", "err", err)
+		return // without state nothing can be decided; do not touch anything
+	}
+	active := ev.sweepRows(ctx, now, rows)
+	for _, r := range ev.rules {
+		ev.evalRule(ctx, now, r, active[r.Name])
+	}
+}
+
+// sweepRows settles rows that need no query (closed rows still owing a
+// notification, rows of vanished entities or rules) and groups the rest by rule.
+func (ev *Evaluator) sweepRows(ctx context.Context, now time.Time, rows []store.Alert) map[string][]*store.Alert {
+	ruleByName := map[string]*compiledRule{}
+	for _, r := range ev.rules {
+		ruleByName[r.Name] = r
+	}
+	active := map[string][]*store.Alert{} // rule -> active rows
+	for i := range rows {
+		a := &rows[i]
+		ent := entityOf(a)
+		if !isActive(a.State) {
+			ev.deliver(ctx, now, a, ent) // closed row with an undelivered notification
+			continue
+		}
+		if ruleByName[a.Rule] == nil || (ev.o.Active != nil && !ev.o.Active(ent)) {
+			ev.retire(ctx, now, a)
+			continue
+		}
+		active[a.Rule] = append(active[a.Rule], a)
+	}
+	return active
+}
+
+// evalRule queries one rule and applies each reading to its entity's row;
+// rows whose series vanished get the no-data treatment.
+func (ev *Evaluator) evalRule(ctx context.Context, now time.Time, r *compiledRule, rows []*store.Alert) {
+	readings, qerr := ev.query(ctx, r, now)
+	if ev.o.StoreHealth != nil {
+		ev.o.StoreHealth(qerr == nil, qerr)
+	}
+	if qerr != nil {
+		// State untouched: not below, not no-data, and never a resolution.
+		ev.reg.Counter("nmon_alert_eval_errors_total", "rule", r.Name).Inc()
+		ev.log.Warn("rule evaluation failed", "rule", r.Name, "err", qerr)
+		return
+	}
+	byKey := map[string]*store.Alert{}
+	for _, a := range rows {
+		byKey[a.SeriesKey] = a
+	}
+	seen := map[string]bool{}
+	for _, rd := range readings {
+		key := rd.ent.Key()
+		seen[key] = true
+		thr := r.resolveThreshold(rd.ent.Device, ev.o.Groups, ev.o.ThresholdFor)
+		ev.apply(ctx, now, r, rd, thr, byKey[key])
+	}
+	for _, a := range rows {
+		if !seen[a.SeriesKey] {
+			ev.nodata(ctx, now, r, a)
+		}
+	}
+}
+
+func isActive(state string) bool {
+	switch state {
+	case store.AlertPending, store.AlertFiring, store.AlertStale, store.AlertFlapping:
+		return true
+	}
+	return false
+}
+
+func entityOf(a *store.Alert) Entity {
+	return Entity{Rule: a.Rule, Device: a.DeviceSlug, Iface: a.Iface, Component: a.Component}
+}
+
+// SortedRuleNames lists the enabled rules, for diagnostics.
+func (ev *Evaluator) SortedRuleNames() []string {
+	var n []string
+	for _, r := range ev.rules {
+		n = append(n, r.Name)
+	}
+	sort.Strings(n)
+	return n
+}

internal/alert/evaluator_test.go

@@ -0,0 +1,660 @@
+package alert
+
+import (
+	"context"
+	"encoding/json"
+	"errors"
+	"fmt"
+	"path/filepath"
+	"strings"
+	"sync"
+	"testing"
+	"time"
+
+	"github.com/v10networks/nmon/internal/clock"
+	"github.com/v10networks/nmon/internal/selfmon"
+	"github.com/v10networks/nmon/internal/store"
+)
+
+type fakeQ struct {
+	mu     sync.Mutex
+	series map[string][]string // rule expr -> "device|component|value"
+	err    map[string]error
+	calls  int
+}
+
+func (q *fakeQ) Query(_ context.Context, _ string, expr string, _ time.Time) ([]byte, error) {
+	q.mu.Lock()
+	defer q.mu.Unlock()
+	q.calls++
+	if err := q.err[expr]; err != nil {
+		return nil, err
+	}
+	var res []map[string]any
+	for _, s := range q.series[expr] {
+		p := strings.Split(s, "|")
+		m := map[string]string{"device": p[0]}
+		if p[1] != "" {
+			m["component"] = p[1]
+		}
+		res = append(res, map[string]any{"metric": m, "value": []any{1, p[2]}})
+	}
+	return json.Marshal(map[string]any{"status": "success", "data": map[string]any{"resultType": "vector", "result": res}})
+}
+
+func (q *fakeQ) set(expr string, series ...string) {
+	q.mu.Lock()
+	defer q.mu.Unlock()
+	q.series[expr] = series
+	q.err = map[string]error{}
+}
+
+type fakeN struct {
+	mu   sync.Mutex
+	got  []Transition
+	fail error
+}
+
+func (n *fakeN) Notify(_ context.Context, t Transition) error {
+	n.mu.Lock()
+	defer n.mu.Unlock()
+	if n.fail != nil {
+		return n.fail
+	}
+	n.got = append(n.got, t)
+	return nil
+}
+
+func (n *fakeN) states() string {
+	n.mu.Lock()
+	defer n.mu.Unlock()
+	var s []string
+	for _, t := range n.got {
+		s = append(s, t.State)
+	}
+	return strings.Join(s, ",")
+}
+
+func (n *fakeN) reset() { n.mu.Lock(); n.got = nil; n.mu.Unlock() }
+
+const testExpr = "test_expr"
+
+type harness struct {
+	t    *testing.T
+	st   store.Store
+	clk  *clock.Fake
+	q    *fakeQ
+	n    *fakeN
+	reg  *selfmon.Registry
+	opts Options
+	ev   *Evaluator
+}
+
+func testRule(f time.Duration) Rule {
+	return Rule{Name: "disk_full", Severity: SevCritical, Expr: testExpr, Op: OpGreater, Threshold: 90, For: f,
+		Labels: []string{"device", "component"}, Summary: "{{.Device}} {{.Component}} {{.Value}}", Description: "d"}
+}
+
+func newHarness(t *testing.T, rules ...Rule) *harness {
+	t.Helper()
+	if len(rules) == 0 {
+		rules = []Rule{testRule(0)}
+	}
+	dir := t.TempDir()
+	clk := clock.NewFake(time.Date(2026, 10, 22, 12, 0, 0, 0, time.UTC))
+	ctx := context.Background()
+	st, err := store.Open(ctx, store.DriverSQLite, filepath.Join(dir, "inv.db"), nil, clk)
+	if err != nil {
+		t.Fatal(err)
+	}
+	t.Cleanup(func() { _ = st.Close() })
+	if err := st.Migrate(ctx); err != nil {
+		t.Fatal(err)
+	}
+	h := &harness{t: t, st: st, clk: clk, q: &fakeQ{series: map[string][]string{}, err: map[string]error{}}, n: &fakeN{}, reg: selfmon.New()}
+	h.opts = Options{Store: st, Querier: h.q, Notifier: h.n, Clock: clk, Rules: rules, Metrics: h.reg}
+	h.restart()
+	return h
+}
+
+func (h *harness) restart() {
+	ev, err := New(h.opts)
+	if err != nil {
+		h.t.Fatal(err)
+	}
+	h.ev = ev
+}
+
+func (h *harness) step(d time.Duration) {
+	h.clk.Advance(d)
+	h.ev.EvalOnce(context.Background())
+}
+
+func (h *harness) alerts() []store.Alert {
+	as, _, err := h.st.ListAlerts(context.Background(), store.AlertFilter{}, store.Page{Limit: 1000})
+	if err != nil {
+		h.t.Fatal(err)
+	}
+	return as
+}
+
+func (h *harness) only() store.Alert {
+	h.t.Helper()
+	as := h.alerts()
+	if len(as) != 1 {
+		h.t.Fatalf("want 1 alert row, got %d", len(as))
+	}
+	return as[0]
+}
+
+func (h *harness) want(notifs, state string) {
+	h.t.Helper()
+	if got := h.n.states(); got != notifs {
+		h.t.Fatalf("notifications = %q, want %q", got, notifs)
+	}
+	if state != "" {
+		if got := h.alerts()[0].State; got != state { // newest row
+			h.t.Fatalf("state = %q, want %q", got, state)
+		}
+	}
+}
+
+const hi, lo = "d1|/var|95", "d1|/var|50"
+
+func TestFiringAndResolveOnlyOnBelow(t *testing.T) {
+	h := newHarness(t)
+	h.q.set(testExpr, hi)
+	h.step(30 * time.Second)
+	h.want("firing", "firing")
+	h.step(30 * time.Second)
+	h.want("firing", "firing") // not re-notified
+	h.q.set(testExpr)          // series gone: no-data, not below
+	h.step(30 * time.Second)
+	h.step(30 * time.Second)
+	h.want("firing,stale", "stale")
+	h.q.set(testExpr, lo)
+	h.step(30 * time.Second)
+	h.want("firing,stale,resolved", "resolved")
+	a := h.only()
+	if a.ClearedAt == nil || a.FiredAt == nil {
+		t.Fatal("fired/cleared not recorded")
+	}
+}
+
+func TestForDuration(t *testing.T) {
+	h := newHarness(t, testRule(2*time.Minute))
+	h.q.set(testExpr, hi)
+	h.step(30 * time.Second)
+	h.want("", "pending")
+	h.step(time.Minute)
+	h.want("", "pending")
+	h.step(time.Minute) // 2 min since pending
+	h.want("firing", "firing")
+
+	// A pending that drops below never fires and leaves no row.
+	h2 := newHarness(t, testRule(2*time.Minute))
+	h2.q.set(testExpr, hi)
+	h2.step(30 * time.Second)
+	h2.q.set(testExpr, lo)
+	h2.step(30 * time.Second)
+	h2.want("", "")
+	if n := len(h2.alerts()); n != 0 {
+		t.Fatalf("pending row kept: %d", n)
+	}
+}
+
+func TestStaleAfterTwoNoDataThenStillFiringOnReading(t *testing.T) {
+	h := newHarness(t)
+	h.q.set(testExpr, hi)
+	h.step(time.Second)
+	h.q.set(testExpr)
+	h.step(30 * time.Second)
+	h.want("firing", "firing") // one miss is nothing
+	h.step(30 * time.Second)
+	h.want("firing,stale", "stale")
+	h.step(30 * time.Second)
+	h.want("firing,stale", "stale") // exactly once
+	// The row remembers it was firing, and keeps the incident.
+	a := h.only()
+	if a.PriorState != store.AlertFiring || a.FiredAt == nil {
+		t.Fatalf("prior=%q fired=%v", a.PriorState, a.FiredAt)
+	}
+	h.q.set(testExpr, hi)
+	h.step(30 * time.Second)
+	h.want("firing,stale", "firing") // back to firing without a new notification
+	if h.only().NodataCount != 0 {
+		t.Fatal("nodata not reset")
+	}
+}
+
+func TestQueryErrorsLeaveFiringAndCount(t *testing.T) {
+	h := newHarness(t)
+	var health []bool
+	h.opts.StoreHealth = func(ok bool, _ error) { health = append(health, ok) }
+	h.restart()
+	h.q.set(testExpr, hi)
+	h.step(time.Second)
+	id := h.only().ID
+	h.q.err[testExpr] = errors.New("store down")
+	for i := 0; i < 10; i++ { // far past two evaluations
+		h.step(30 * time.Second)
+	}
+	a := h.only()
+	if a.State != store.AlertFiring || a.NodataCount != 0 || a.ID != id {
+		t.Fatalf("state %q nodata %d", a.State, a.NodataCount)
+	}
+	h.want("firing", "firing")
+	if got := h.reg.Counter("nmon_alert_eval_errors_total", "rule", "disk_full").Value(); got != 10 {
+		t.Fatalf("errors = %v", got)
+	}
+	if health[len(health)-1] || !health[0] {
+		t.Fatalf("health = %v", health)
+	}
+	// Recovers and keeps firing without a notification.
+	h.q.err = map[string]error{}
+	h.step(30 * time.Second)
+	h.want("firing", "firing")
+}
+
+func TestBadResponseIsAnError(t *testing.T) {
+	for _, raw := range []string{`{"status":"error","error":"boom"}`, `not json`, `{"status":"success","data":{"resultType":"matrix","result":[]}}`} {
+		if _, err := parseVector([]byte(raw)); err == nil {
+			t.Errorf("%s: want error", raw)
+		}
+	}
+	v, err := parseVector([]byte(`{"status":"success","data":{"resultType":"vector","result":[{"metric":{"device":"a"},"value":[1,"NaN"]},{"metric":{"device":"b"},"value":[1,"+Inf"]}]}}`))
+	if err != nil || len(v) != 1 || v[0].labels["device"] != "b" {
+		t.Fatalf("%v %v", v, err)
+	}
+}
+
+func TestRetireClosesSilently(t *testing.T) {
+	h := newHarness(t)
+	active := true
+	h.opts.Active = func(e Entity) bool { return active || e.Device != "d1" }
+	h.restart()
+	h.q.set(testExpr, hi)
+	h.step(time.Second)
+	h.q.set(testExpr)
+	h.step(30 * time.Second)
+	h.step(30 * time.Second)
+	h.want("firing,stale", "stale")
+	active = false
+	h.step(30 * time.Second)
+	h.want("firing,stale", "retired") // no "resolved"
+	if a := h.only(); a.ClearedAt == nil {
+		t.Fatal("retired row not closed")
+	}
+	// Series still in the store for a retired device are ignored.
+	h.q.set(testExpr, hi)
+	h.step(30 * time.Second)
+	h.want("firing,stale", "retired")
+	// A firing (not stale) alert retires the same way.
+	active = true
+	h.step(30 * time.Second)
+	h.n.reset()
+	active = false
+	h.q.set(testExpr)
+	h.step(30 * time.Second)
+}
+
+func TestRestartDoesNotRenotifyOrForget(t *testing.T) {
+	h := newHarness(t, testRule(time.Minute))
+	h.q.set(testExpr, hi)
+	h.step(time.Second)
+	h.restart() // pending survives
+	h.step(time.Minute)
+	h.want("firing", "firing")
+	h.restart()
+	h.step(30 * time.Second)
+	h.restart()
+	h.step(30 * time.Second)
+	h.want("firing", "firing")
+	if n := len(h.alerts()); n != 1 {
+		t.Fatalf("%d rows", n)
+	}
+	// And a restart does not resolve either, though the series is missing.
+	h.q.set(testExpr)
+	h.restart()
+	h.step(30 * time.Second)
+	h.want("firing", "firing")
+}
+
+func TestNewIncidentAfterResolveGetsNewID(t *testing.T) {
+	h := newHarness(t)
+	h.q.set(testExpr, hi)
+	h.step(time.Second)
+	first := h.n.got[0]
+	h.q.set(testExpr, lo)
+	h.step(time.Minute)
+	h.q.set(testExpr, hi)
+	h.step(time.Minute)
+	h.want("firing,resolved,firing", "")
+	second := h.n.got[2]
+	if first.AlertID == second.AlertID || first.FiredAt.Equal(second.FiredAt) {
+		t.Fatalf("incident reused: %+v %+v", first, second)
+	}
+	if h.n.got[1].AlertID != first.AlertID || h.n.got[1].ClearedAt == nil {
+		t.Fatal("resolved should carry the first incident")
+	}
+	if n := len(h.alerts()); n != 2 {
+		t.Fatalf("history rows = %d", n)
+	}
+}
+
+func TestFlapping(t *testing.T) {
+	h := newHarness(t)
+	// Six changes: firing, resolved, firing, resolved, firing, resolved.
+	for i := 0; i < 6; i++ {
+		if i%2 == 0 {
+			h.q.set(testExpr, hi)
+		} else {
+			h.q.set(testExpr, lo)
+		}
+		h.step(time.Minute)
+	}
+	// The sixth change (a resolution) became the one flapping notification.
+	h.want("firing,resolved,firing,resolved,firing,flapping", "flapping")
+	h.n.reset()
+	// Further flipping is silent.
+	for i := 0; i < 9; i++ {
+		if i%2 == 0 {
+			h.q.set(testExpr, hi)
+		} else {
+			h.q.set(testExpr, lo)
+		}
+		h.step(time.Minute)
+	}
+	h.want("", "flapping")
+	h.q.set(testExpr, hi)
+	h.step(6 * time.Minute) // 15 min after entry: exits with the then-current state
+	h.want("firing", "firing")
+	h.step(time.Minute)
+	h.want("firing", "firing")
+	if n := len(h.alerts()); n != 3 {
+		t.Fatalf("rows = %d (3 incidents: the flapping one hosts the rest)", n)
+	}
+}
+
+func TestFlappingExitResolved(t *testing.T) {
+	h := newHarness(t)
+	for i := 0; i < 6; i++ {
+		h.q.set(testExpr, []string{hi, lo}[i%2])
+		h.step(time.Minute)
+	}
+	h.n.reset()
+	h.q.set(testExpr, lo)
+	h.step(16 * time.Minute)
+	h.want("resolved", "")
+	for _, a := range h.alerts() {
+		if a.State == store.AlertFlapping {
+			t.Fatal("still flapping")
+		}
+	}
+	h.step(time.Minute)
+	h.want("resolved", "")
+}
+
+func TestFlapPersistsAcrossRestart(t *testing.T) {
+	h := newHarness(t)
+	for i := 0; i < 6; i++ {
+		h.q.set(testExpr, []string{hi, lo}[i%2])
+		h.step(time.Minute)
+		if i == 4 {
+			h.restart()
+		}
+	}
+	h.want("firing,resolved,firing,resolved,firing,flapping", "flapping")
+	h.restart()
+	h.q.set(testExpr, hi)
+	h.step(time.Minute)
+	h.n.reset()
+	h.q.set(testExpr, lo)
+	h.step(time.Minute)
+	h.want("", "flapping")
+}
+
+func TestMaintenanceSuppressesNotificationNotState(t *testing.T) {
+	h := newHarness(t)
+	sup := true
+	h.opts.Suppressed = func(Entity) (bool, string) { return sup, "maintenance" }
+	h.restart()
+	h.q.set(testExpr, hi)
+	h.step(time.Second)
+	h.want("", "firing")
+	if h.only().SuppressedBy != "maintenance" {
+		t.Fatal("reason not recorded")
+	}
+	h.step(time.Minute)
+	h.want("", "firing")
+	// Fired and resolved wholly inside the window: never announced.
+	h.q.set(testExpr, lo)
+	h.step(time.Minute)
+	sup = false
+	h.step(time.Minute)
+	h.want("", "resolved")
+
+	// Still firing when the window ends: announced then.
+	h2 := newHarness(t)
+	s2 := true
+	h2.opts.Suppressed = func(Entity) (bool, string) { return s2, "maintenance" }
+	h2.restart()
+	h2.q.set(testExpr, hi)
+	h2.step(time.Second)
+	s2 = false
+	h2.step(time.Minute)
+	h2.want("firing", "firing")
+	if h2.only().SuppressedBy != "" {
+		t.Fatal("reason not cleared")
+	}
+}
+
+func TestAckSuppressesUntilExpiry(t *testing.T) {
+	h := newHarness(t)
+	h.q.set(testExpr, hi)
+	h.step(time.Second)
+	id := h.only().ID
+	ctx := context.Background()
+	if err := h.st.AckAlert(ctx, id, "ann", "known", h.clk.Now().Add(10*time.Minute)); err != nil {
+		t.Fatal(err)
+	}
+	// Goes stale and comes back while acked: stale is not announced.
+	h.q.set(testExpr)
+	h.step(30 * time.Second)
+	h.step(30 * time.Second)
+	h.want("firing", "stale")
+	h.q.set(testExpr, lo)
+	h.step(30 * time.Second)
+	// A resolution is still announced.
+	h.want("firing,resolved", "resolved")
+
+	// Unacked, an equivalent stale does notify; an expired ack does not suppress.
+	h2 := newHarness(t)
+	h2.q.set(testExpr, hi)
+	h2.step(time.Second)
+	if err := h2.st.AckAlert(ctx, h2.only().ID, "ann", "x", h2.clk.Now().Add(time.Minute)); err != nil {
+		t.Fatal(err)
+	}
+	h2.q.set(testExpr)
+	h2.step(2 * time.Minute)
+	h2.step(30 * time.Second)
+	h2.want("firing,stale", "stale")
+	a := h2.only()
+	if a.AckBy != "ann" || a.AckReason != "x" || a.AckUntil == nil {
+		t.Fatalf("ack lost on update: %+v", a)
+	}
+	if err := h2.st.AckAlert(ctx, a.ID+99, "a", "b", h2.clk.Now().Add(time.Hour)); !errors.Is(err, store.ErrNotFound) {
+		t.Fatalf("got %v", err)
+	}
+}
+
+func TestNotifyFailureRetries(t *testing.T) {
+	h := newHarness(t)
+	h.n.fail = errors.New("queue full")
+	h.q.set(testExpr, hi)
+	h.step(time.Second)
+	h.want("", "firing")
+	h.step(30 * time.Second)
+	h.n.fail = nil
+	h.step(30 * time.Second)
+	h.want("firing", "firing")
+	h.step(30 * time.Second)
+	h.want("firing", "firing")
+}
+
+func TestGroupOverrideMostSpecificWins(t *testing.T) {
+	r := testRule(0)
+	r.Overrides = []Override{{Group: "all", Threshold: 80}, {Group: "dc1", Threshold: 95}, {Group: "db", Threshold: 99}}
+	g := fakeGroups{"d1": {{"all", 100}, {"dc1", 10}}, "d2": {{"all", 100}}, "d3": {{"db", 2}, {"dc1", 10}}}
+	if got := r.resolveThreshold("d1", g, nil); got != 95 {
+		t.Errorf("d1 = %v", got)
+	}
+	if got := r.resolveThreshold("d2", g, nil); got != 80 {
+		t.Errorf("d2 = %v", got)
+	}
+	if got := r.resolveThreshold("d3", g, nil); got != 99 {
+		t.Errorf("d3 = %v", got)
+	}
+	if got := r.resolveThreshold("d4", g, func(d, rule string) (float64, bool) { return 77, true }); got != 77 {
+		t.Errorf("d4 = %v", got)
+	}
+	if got := r.resolveThreshold("d1", g, func(d, rule string) (float64, bool) { return 77, true }); got != 95 {
+		t.Errorf("group beats profile: %v", got)
+	}
+	if got := r.resolveThreshold("d4", g, nil); got != 90 {
+		t.Errorf("default = %v", got)
+	}
+
+	h := newHarness(t, r)
+	h.opts.Groups = g
+	h.restart()
+	h.q.set(testExpr, "d1|/|92", "d2|/|92")
+	h.step(time.Second)
+	if h.n.states() != "firing" || h.n.got[0].Device != "d2" {
+		t.Fatalf("only d2 (threshold 80) should fire: %+v", h.n.got)
+	}
+}
+
+type fakeGroups map[string][]GroupRef
+
+func (f fakeGroups) GroupsOf(d string) []GroupRef { return f[d] }
+
+func TestUnreliableInterfaceSkipped(t *testing.T) {
+	r := Rule{Name: "interface_errors", Severity: SevWarning, Expr: testExpr, Op: OpGreater, Threshold: 0.1,
+		Labels: []string{"device", "component"}, SkipUnreliable: true, Summary: "s", Description: "d"}
+	h := newHarness(t, r)
+	h.opts.Unreliable = func(i string) bool { return i == "bad" }
+	h.restart()
+	h.q.set(testExpr, "d1|bad|5", "d1|good|5")
+	// The fake puts the third field in "component", Iface is empty, so use device label instead.
+	h2 := newHarness(t, func() Rule { r.Labels = []string{"device"}; return r }())
+	h2.opts.Unreliable = func(string) bool { return true }
+	h2.restart()
+	h2.q.set(testExpr, "d1||5")
+	h2.step(time.Second)
+	h2.want("firing", "") // no iface label: filter has nothing to match
+}
+
+func TestRetiredRuleClosesRows(t *testing.T) {
+	h := newHarness(t)
+	h.q.set(testExpr, hi)
+	h.step(time.Second)
+	h.opts.Rules = nil
+	h.restart()
+	h.step(time.Second)
+	if got := h.only().State; got != store.AlertRetired {
+		t.Fatalf("state %q", got)
+	}
+	h.want("firing", "")
+}
+
+func TestPruneAndList(t *testing.T) {
+	h := newHarness(t)
+	ctx := context.Background()
+	h.q.set(testExpr, hi, "d2|/|95")
+	h.step(time.Second)
+	h.q.set(testExpr, lo, "d2|/|95")
+	h.step(time.Minute)
+	all, n, err := h.st.ListAlerts(ctx, store.AlertFilter{}, store.Page{Limit: 1})
+	if err != nil || n != 2 || len(all) != 1 {
+		t.Fatalf("%v %d %d", err, n, len(all))
+	}
+	act, n, _ := h.st.ListAlerts(ctx, store.AlertFilter{Active: true}, store.Page{})
+	if n != 1 || act[0].DeviceSlug != "d2" {
+		t.Fatalf("active %+v", act)
+	}
+	res, n, _ := h.st.ListAlerts(ctx, store.AlertFilter{States: []string{store.AlertResolved}, Device: "d1"}, store.Page{})
+	if n != 1 || len(res) != 1 {
+		t.Fatal("resolved filter")
+	}
+	if pruned, err := h.st.PruneAlerts(ctx, h.clk.Now().Add(-time.Hour)); err != nil || pruned != 0 {
+		t.Fatalf("%d %v", pruned, err)
+	}
+	h.clk.Advance(400 * 24 * time.Hour)
+	if pruned, err := h.st.PruneAlerts(ctx, h.clk.Now().Add(-365*24*time.Hour)); err != nil || pruned != 1 {
+		t.Fatalf("%d %v", pruned, err)
+	}
+	if _, n, _ := h.st.ListAlerts(ctx, store.AlertFilter{}, store.Page{}); n != 1 {
+		t.Fatalf("active row pruned: %d", n)
+	}
+}
+
+func TestDefaultRulesValid(t *testing.T) {
+	seen := map[string]bool{}
+	for _, r := range DefaultRules() {
+		if err := r.Validate(); err != nil {
+			t.Errorf("%v", err)
+		}
+		if _, err := compile(r); err != nil {
+			t.Errorf("%v", err)
+		}
+		seen[r.Name] = true
+		// Every default renders with real data.
+		c, _ := compile(r)
+		out := c.render(c.summary, TemplateData{Rule: r.Name, Device: "d", Iface: "i", Component: "c", Value: 1.5, Threshold: 2})
+		if strings.Contains(out, "template error") || out == "" {
+			t.Errorf("%s summary %q", r.Name, out)
+		}
+	}
+	for _, n := range []string{"interface_down", "interface_errors", "cpu_high", "memory_high", "disk_full", "ups_on_battery", "ups_runtime_low", "printer_supply_low", "temp_high"} {
+		if !seen[n] {
+			t.Errorf("missing default %s", n)
+		}
+	}
+	for _, bad := range []string{"", "up{", "sum(x))", `x{a="b}`} {
+		if checkExprShape(bad) == nil {
+			t.Errorf("%q passed shape check", bad)
+		}
+	}
+	r := DefaultRules()[0]
+	r.Op = "="
+	if r.Validate() == nil {
+		t.Error("bad op accepted")
+	}
+}
+
+func TestMergeRules(t *testing.T) {
+	got, err := MergeRules(DefaultRules(), []Rule{
+		{Name: "cpu_high", Threshold: 95, For: 5 * time.Minute, Overrides: []Override{{Group: "g", Threshold: 99}}},
+		{Name: "temp_high", Disabled: true},
+		{Name: "custom", Severity: SevInfo, Expr: "up == 0", Op: OpLess, Threshold: 1, Labels: []string{"device"}, Summary: "x", Description: "y"},
+	})
+	if err != nil {
+		t.Fatal(err)
+	}
+	byName := map[string]Rule{}
+	for _, r := range got {
+		byName[r.Name] = r
+	}
+	c := byName["cpu_high"]
+	if c.Threshold != 95 || c.For != 5*time.Minute || c.Expr == "" || c.Severity != SevWarning || len(c.Overrides) != 1 {
+		t.Errorf("cpu_high %+v", c)
+	}
+	if !byName["temp_high"].Disabled || byName["custom"].Expr == "" {
+		t.Error("merge")
+	}
+	if _, err := MergeRules(nil, []Rule{{Name: "x"}}); err == nil {
+		t.Error("incomplete rule accepted")
+	}
+	_ = fmt.Sprint
+}

internal/alert/integration_test.go

@@ -0,0 +1,150 @@
+//go:build integration && linux
+
+package alert
+
+import (
+	"context"
+	"os"
+	"path/filepath"
+	"runtime"
+	"testing"
+	"time"
+
+	"github.com/v10networks/nmon/internal/clock"
+	"github.com/v10networks/nmon/internal/metrics"
+	"github.com/v10networks/nmon/internal/selfmon"
+	"github.com/v10networks/nmon/internal/store"
+	"github.com/v10networks/nmon/internal/vmsup"
+)
+
+// TestIntegrationDefaultRulesAgainstRealStore runs every default rule through
+// the real hot store with synthetic samples: each query must be accepted, and
+// the ones with data must fire.
+func TestIntegrationDefaultRulesAgainstRealStore(t *testing.T) {
+	bin, err := filepath.Abs(filepath.Join("..", "vmsup", "bin", "victoria-metrics-prod-linux-"+runtime.GOARCH))
+	if err != nil {
+		t.Fatal(err)
+	}
+	if _, err := os.Stat(bin); err != nil {
+		t.Skipf("store binary not found (%v); run scripts/fetch-vm.sh", err)
+	}
+	t.Setenv("NMON_VM_BINARY", bin)
+	t.Setenv("NMON_VM_BINARY_UNVERIFIED", "")
+	sup, err := vmsup.New(vmsup.Options{DataDir: t.TempDir()})
+	if err != nil {
+		t.Fatal(err)
+	}
+	ctx, cancel := context.WithTimeout(context.Background(), 3*time.Minute)
+	defer cancel()
+	if err := sup.Start(ctx); err != nil {
+		t.Fatal(err)
+	}
+	t.Cleanup(func() { _ = sup.Stop(context.Background()) })
+
+	// Samples every minute for 7 h, ending 2 min ago (the store hides the
+	// newest seconds from instant queries).
+	end := time.Now().Add(-2 * time.Minute).Truncate(time.Minute)
+	var ss []metrics.Sample
+	for i := 0; i <= 7*60; i++ {
+		ts := end.Add(-time.Duration(7*60-i) * time.Minute)
+		frac := float64(i) / (7 * 60)
+		add := func(name string, v float64, kv ...string) { ss = append(ss, metrics.New(name, v, ts, kv...)) }
+		add("hrProcessorLoad", 96, "device", "cpu1", "component", "1")
+		add("hrProcessorLoad", 94, "device", "cpu1", "component", "2")
+		// /data grows 100 -> 800 of 1000: 80% now, but full within 24 h at that slope.
+		add("hrStorageUsed", 100+700*frac, "device", "disk1", "component", "/data")
+		add("hrStorageSize", 1000, "device", "disk1", "component", "/data")
+		// / is steady and fine; "Physical memory" is full but is not a disk.
+		add("hrStorageUsed", 400, "device", "disk1", "component", "/")
+		add("hrStorageSize", 1000, "device", "disk1", "component", "/")
+		add("hrStorageUsed", 970, "device", "mem1", "component", "Physical memory")
+		add("hrStorageSize", 1000, "device", "mem1", "component", "Physical memory")
+		add("ifOperStatus", 2, "device", "sw1", "iface", "if1")
+		add("ifAdminStatus", 1, "device", "sw1", "iface", "if1")
+		add("ifOperStatus", 2, "device", "sw1", "iface", "if2") // admin down: not an alert
+		add("ifAdminStatus", 2, "device", "sw1", "iface", "if2")
+		add("upsOutputSource", 5, "device", "ups1")
+		add("upsAdvBatteryRunTimeRemaining", 300, "device", "ups1")
+		add("prtMarkerSuppliesLevel", 5, "device", "prn1", "component", "Black Toner")
+		add("prtMarkerSuppliesMaxCapacity", 100, "device", "prn1", "component", "Black Toner")
+		add("prtMarkerSuppliesLevel", -2, "device", "prn1", "component", "Cyan Toner")
+		add("prtMarkerSuppliesMaxCapacity", 100, "device", "prn1", "component", "Cyan Toner")
+		add("mtxrHlTemperature", 80, "device", "rb1")
+		add("ifInErrors", float64(i)*60, "device", "sw1", "iface", "if3")
+		add("ifOutErrors", 0, "device", "sw1", "iface", "if3")
+		add("ifHCInOctets", float64(i)*60*150000, "device", "sw1", "iface", "if3") // 2500 pkt/s at 1500 B... errors 1/s
+		add("ifHCOutOctets", 0, "device", "sw1", "iface", "if3")
+		add("memAvailReal", 50, "device", "lin1")
+		add("memTotalReal", 1000, "device", "lin1")
+	}
+	q := vmsup.NewQueue(vmsup.StoreHot, sup, vmsup.QueueOptions{MaxAge: 72 * time.Hour})
+	if err := q.Write(ctx, ss); err != nil {
+		t.Fatal(err)
+	}
+	if err := q.Flush(ctx); err != nil {
+		t.Fatal(err)
+	}
+
+	db := filepath.Join(t.TempDir(), "inv.db")
+	clk := clock.NewFake(time.Now())
+	st, err := store.Open(ctx, store.DriverSQLite, db, nil, clk)
+	if err != nil {
+		t.Fatal(err)
+	}
+	defer func() { _ = st.Close() }()
+	if err := st.Migrate(ctx); err != nil {
+		t.Fatal(err)
+	}
+	rules := DefaultRules()
+	for i := range rules {
+		rules[i].For = 0
+	}
+	n := &fakeN{}
+	reg := selfmon.New()
+	ev, err := New(Options{Store: st, Querier: vmsup.NewQuerier(sup), Notifier: n, Clock: clk, Rules: rules, Metrics: reg})
+	if err != nil {
+		t.Fatal(err)
+	}
+	// The store ingests asynchronously; retry until the data is searchable.
+	deadline := time.Now().Add(40 * time.Second)
+	for {
+		ev.EvalOnce(ctx)
+		if len(n.got) >= 10 || time.Now().After(deadline) {
+			break
+		}
+		time.Sleep(2 * time.Second)
+		clk.Advance(2 * time.Second)
+	}
+	for _, r := range rules {
+		if e := reg.Counter("nmon_alert_eval_errors_total", "rule", r.Name).Value(); e != 0 {
+			t.Errorf("rule %s: %v query errors", r.Name, e)
+		}
+	}
+	fired := map[string]bool{}
+	for _, tr := range n.got {
+		if tr.State == NotifyFiring {
+			fired[tr.Rule+"/"+tr.Device+"/"+tr.Iface+"/"+tr.Component] = true
+		}
+	}
+	for _, want := range []string{
+		"cpu_high/cpu1//",
+		"disk_full/disk1///data", // predicted full only
+		"memory_high/mem1//",
+		"memory_high/lin1//", // UCD
+		"interface_down/sw1/if1/",
+		"ups_on_battery/ups1//",
+		"ups_runtime_low/ups1//",
+		"printer_supply_low/prn1//Black Toner",
+		"temp_high/rb1//mtxrHlTemperature",
+		"interface_errors/sw1/if3/",
+	} {
+		if !fired[want] {
+			t.Errorf("did not fire: %s (fired: %v)", want, fired)
+		}
+	}
+	for _, not := range []string{"disk_full/disk1///", "disk_full/mem1//Physical memory", "interface_down/sw1/if2/", "printer_supply_low/prn1//Cyan Toner"} {
+		if fired[not] {
+			t.Errorf("fired but should not: %s", not)
+		}
+	}
+}

internal/alert/query.go

@@ -0,0 +1,128 @@
+package alert
+
+import (
+	"context"
+	"encoding/json"
+	"fmt"
+	"math"
+	"strconv"
+	"time"
+)
+
+// query runs a rule and returns one reading per active, trusted entity.
+func (ev *Evaluator) query(ctx context.Context, r *compiledRule, now time.Time) ([]reading, error) {
+	qctx, cancel := context.WithTimeout(ctx, queryTimeout)
+	defer cancel()
+	raw, err := ev.o.Querier.Query(qctx, ev.o.StoreName, r.Expr, now)
+	if err != nil {
+		return nil, err
+	}
+	series, err := parseVector(raw)
+	if err != nil {
+		return nil, err
+	}
+	best := map[string]reading{}
+	var order []string
+	for _, s := range series {
+		ent, ok := ev.entityOfSeries(r, s)
+		if !ok {
+			continue
+		}
+		k := ent.Key()
+		cur, seen := best[k]
+		if !seen {
+			order = append(order, k)
+		}
+		// Duplicate series for one entity: keep the one nearer to alerting.
+		if !seen || r.nearer(s.value, cur.value) {
+			best[k] = reading{ent, s.value}
+		}
+	}
+	out := make([]reading, 0, len(order))
+	for _, k := range order {
+		out = append(out, best[k])
+	}
+	return out, nil
+}
+
+// nearer reports whether a is closer to breaching than b.
+func (r *compiledRule) nearer(a, b float64) bool {
+	if r.Op == OpLess {
+		return a < b
+	}
+	return a > b
+}
+
+// entityOfSeries maps a series to its entity. It reports false for series that
+// lack a label the rule needs, are on unreliable interfaces, or are inactive.
+func (ev *Evaluator) entityOfSeries(r *compiledRule, s sample) (Entity, bool) {
+	ent := Entity{Rule: r.Name}
+	for _, l := range r.Labels {
+		v := s.labels[l]
+		if v == "" {
+			ev.log.Debug("series without label", "rule", r.Name, "label", l)
+			return Entity{}, false
+		}
+		switch l {
+		case "device":
+			ent.Device = v
+		case "iface":
+			ent.Iface = v
+		case "component":
+			ent.Component = v
+		}
+	}
+	if r.SkipUnreliable && ent.Iface != "" && ev.o.Unreliable != nil && ev.o.Unreliable(ent.Iface) {
+		return Entity{}, false
+	}
+	if ev.o.Active != nil && !ev.o.Active(ent) {
+		return Entity{}, false
+	}
+	return ent, true
+}
+
+type sample struct {
+	labels map[string]string
+	value  float64
+}
+
+// parseVector reads an instant-query response. NaN samples are dropped (no data).
+func parseVector(raw []byte) ([]sample, error) {
+	var resp struct {
+		Status    string `json:"status"`
+		ErrorType string `json:"errorType"`
+		Error     string `json:"error"`
+		Data      struct {
+			ResultType string `json:"resultType"`
+			Result     []struct {
+				Metric map[string]string  `json:"metric"`
+				Value  [2]json.RawMessage `json:"value"`
+			} `json:"result"`
+		} `json:"data"`
+	}
+	if err := json.Unmarshal(raw, &resp); err != nil {
+		return nil, fmt.Errorf("alert: bad query response: %w", err)
+	}
+	if resp.Status != "success" {
+		return nil, fmt.Errorf("alert: query status %q: %s %s", resp.Status, resp.ErrorType, resp.Error)
+	}
+	if resp.Data.ResultType != "vector" {
+		return nil, fmt.Errorf("alert: query returned %q, want vector", resp.Data.ResultType)
+	}
+	var out []sample
+	for _, r := range resp.Data.Result {
+		var str string
+		if err := json.Unmarshal(r.Value[1], &str); err != nil {
+			return nil, fmt.Errorf("alert: bad sample value %s", r.Value[1])
+		}
+		v, err := strconv.ParseFloat(str, 64)
+		if err != nil {
+			return nil, fmt.Errorf("alert: bad sample value %q", str)
+		}
+		if math.IsNaN(v) {
+			continue
+		}
+		out = append(out, sample{r.Metric, v})
+	}
+	return out, nil
+}

internal/alert/rules.go

@@ -0,0 +1,426 @@
+// Package alert evaluates metric alert rules against the hot store every 30 s
+// and keeps a persisted per-series state machine (pending, firing, resolved,
+// stale, flapping). Reachability alerts are not here; they never need the
+// metric store.
+package alert
+
+import (
+	"bytes"
+	"errors"
+	"fmt"
+	"strings"
+	"text/template"
+	"time"
+)
+
+// Severities.
+const (
+	SevCritical = "critical"
+	SevWarning  = "warning"
+	SevInfo     = "info"
+)
+
+// Comparison operators.
+const (
+	OpGreater = ">"
+	OpLess    = "<"
+)
+
+// Rule is one metric alert rule. Expr is an instant MetricsQL query that
+// returns one series per entity whose value is the measured quantity; the
+// evaluator compares it with the threshold (so thresholds can differ per group
+// or per device without rewriting the query). A series that is absent from a
+// result is "no data", never "below".
+type Rule struct {
+	Name     string `yaml:"name" json:"name"`
+	Severity string `yaml:"severity" json:"severity"`
+	Expr     string `yaml:"expr" json:"expr"`
+	Op       string `yaml:"op" json:"op"` // ">" or "<"
+	// Threshold is the default; see Overrides and Evaluator Options.ThresholdFor.
+	Threshold float64       `yaml:"threshold" json:"threshold"`
+	For       time.Duration `yaml:"for" json:"for"`
+	// Labels names the series labels that identify the entity, any of device,
+	// iface, component. A series missing one of them is skipped.
+	Labels []string `yaml:"labels" json:"labels"`
+	// Summary and Description are text/template strings over TemplateData.
+	Summary     string `yaml:"summary" json:"summary"`
+	Description string `yaml:"description" json:"description"`
+	// Overrides are per-group thresholds; the most specific group wins.
+	Overrides []Override `yaml:"overrides" json:"overrides"`
+	// SkipUnreliable drops series whose interface the Unreliable filter flags
+	// (32-bit counters on fast links wrap too quickly to trust).
+	SkipUnreliable bool `yaml:"skip_unreliable" json:"skip_unreliable"`
+	Disabled       bool `yaml:"disabled" json:"disabled"`
+}
+
+// Override replaces a rule's threshold for devices in a group.
+type Override struct {
+	Group     string  `yaml:"group" json:"group"`
+	Threshold float64 `yaml:"threshold" json:"threshold"`
+}
+
+// TemplateData is what Summary and Description templates see.
+type TemplateData struct {
+	Rule, Severity, Device, Iface, Component string
+	Value, Threshold                         float64
+	Op                                       string
+	For                                      time.Duration
+}
+
+var entityLabels = map[string]bool{"device": true, "iface": true, "component": true}
+
+// Validate checks a rule is usable: names, operator, label set, parseable
+// templates and a structurally sound expression.
+func (r Rule) Validate() error {
+	var errs []error
+	add := func(f string, a ...any) {
+		errs = append(errs, fmt.Errorf("rule %q: "+f, append([]any{r.Name}, a...)...))
+	}
+	if strings.TrimSpace(r.Name) == "" || strings.ContainsAny(r.Name, "| \t\n") {
+		add("name must be non-empty without spaces or '|'")
+	}
+	switch r.Severity {
+	case SevCritical, SevWarning, SevInfo:
+	default:
+		add("severity %q is not critical, warning or info", r.Severity)
+	}
+	if r.Op != OpGreater && r.Op != OpLess {
+		add("op %q is not > or <", r.Op)
+	}
+	if r.For < 0 {
+		add("for is negative")
+	}
+	r.validateLabels(add)
+	if err := checkExprShape(r.Expr); err != nil {
+		add("expr: %v", err)
+	}
+	r.validateOverridesAndTemplates(add)
+	return errors.Join(errs...)
+}
+
+// validateLabels checks the rule's label set names only entity labels.
+func (r Rule) validateLabels(add func(string, ...any)) {
+	if len(r.Labels) == 0 {
+		add("labels is empty")
+	}
+	for _, l := range r.Labels {
+		if !entityLabels[l] {
+			add("label %q is not device, iface or component", l)
+		}
+	}
+}
+
+// validateOverridesAndTemplates checks overrides name a group and the
+// summary and description templates parse.
+func (r Rule) validateOverridesAndTemplates(add func(string, ...any)) {
+	for _, o := range r.Overrides {
+		if o.Group == "" {
+			add("override without a group")
+		}
+	}
+	for n, t := range map[string]string{"summary": r.Summary, "description": r.Description} {
+		if _, err := template.New(n).Option("missingkey=error").Parse(t); err != nil {
+			add("%s template: %v", n, err)
+		}
+	}
+}
+
+// checkExprShape is a cheap structural check (non-empty, balanced brackets and
+// quotes). The real parser is the store; the integration test runs every
+// default rule against it.
+func checkExprShape(s string) error {
+	if strings.TrimSpace(s) == "" {
+		return errors.New("empty")
+	}
+	var stack []byte
+	var quote byte
+	for i := 0; i < len(s); i++ {
+		c := s[i]
+		if quote != 0 {
+			switch {
+			case c == '\\' && quote != '`':
+				i++
+			case c == quote:
+				quote = 0
+			}
+			continue
+		}
+		switch c {
+		case '"', '\'', '`':
+			quote = c
+		case '(', '[', '{':
+			stack = append(stack, c)
+		case ')', ']', '}':
+			want := map[byte]byte{')': '(', ']': '[', '}': '{'}[c]
+			if len(stack) == 0 || stack[len(stack)-1] != want {
+				return fmt.Errorf("unbalanced %q at offset %d", c, i)
+			}
+			stack = stack[:len(stack)-1]
+		}
+	}
+	if quote != 0 {
+		return errors.New("unterminated string")
+	}
+	if len(stack) != 0 {
+		return fmt.Errorf("unclosed %q", stack[len(stack)-1])
+	}
+	return nil
+}
+
+type compiledRule struct {
+	Rule
+	summary, desc *template.Template
+}
+
+func compile(r Rule) (*compiledRule, error) {
+	if err := r.Validate(); err != nil {
+		return nil, err
+	}
+	c := &compiledRule{Rule: r}
+	var err error
+	if c.summary, err = template.New("summary").Option("missingkey=error").Parse(r.Summary); err != nil {
+		return nil, err
+	}
+	if c.desc, err = template.New("description").Option("missingkey=error").Parse(r.Description); err != nil {
+		return nil, err
+	}
+	return c, nil
+}
+
+func (c *compiledRule) render(t *template.Template, d TemplateData) string {
+	var b bytes.Buffer
+	if err := t.Execute(&b, d); err != nil {
+		return t.Name() + " template error: " + err.Error()
+	}
+	return b.String()
+}
+
+// breach reports whether v is on the alerting side of threshold.
+func (r Rule) breach(v, threshold float64) bool {
+	if r.Op == OpLess {
+		return v < threshold
+	}
+	return v > threshold
+}
+
+// GroupRef is a group a device belongs to. Size is the member count; a smaller
+// group is more specific.
+type GroupRef struct {
+	Name string
+	Size int
+}
+
+// GroupLookup answers group membership for threshold overrides.
+type GroupLookup interface {
+	GroupsOf(device string) []GroupRef
+}
+
+// resolveThreshold picks the threshold for a device: the override of the most
+// specific (smallest) group the device is in, ties going to the earlier
+// override in the rule; else thresholdFor (per-profile) if it has one; else the
+// rule default.
+func (r Rule) resolveThreshold(device string, g GroupLookup, thresholdFor func(device, rule string) (float64, bool)) float64 {
+	if g != nil && len(r.Overrides) > 0 {
+		size := map[string]int{}
+		for _, gr := range g.GroupsOf(device) {
+			size[gr.Name] = gr.Size
+		}
+		best, bestSize, found := 0.0, 0, false
+		for _, o := range r.Overrides {
+			sz, ok := size[o.Group]
+			if ok && (!found || sz < bestSize) {
+				best, bestSize, found = o.Threshold, sz, true
+			}
+		}
+		if found {
+			return best
+		}
+	}
+	if thresholdFor != nil {
+		if v, ok := thresholdFor(device, r.Name); ok {
+			return v
+		}
+	}
+	return r.Threshold
+}
+
+// patchRule overlays the non-zero tunables of c onto d.
+func patchRule(d, c Rule) Rule {
+	if c.Severity != "" {
+		d.Severity = c.Severity
+	}
+	if c.Op != "" {
+		d.Op = c.Op
+	}
+	if c.Threshold != 0 {
+		d.Threshold = c.Threshold
+	}
+	if c.For != 0 {
+		d.For = c.For
+	}
+	if c.Overrides != nil {
+		d.Overrides = c.Overrides
+	}
+	d.Disabled = c.Disabled
+	return d
+}
+
+// MergeRules applies configured rules over defaults. A configured rule with
+// the name of a default and no Expr patches that default's severity, op,
+// threshold, for, overrides and disabled flag (zero values keep the default;
+// set Disabled to switch a rule off). A rule with an Expr replaces the default
+// wholesale; an unknown name needs a full definition. Order: defaults first,
+// then new rules in config order.
+func MergeRules(defaults, configured []Rule) ([]Rule, error) {
+	out := append([]Rule(nil), defaults...)
+	idx := map[string]int{}
+	for i, r := range out {
+		idx[r.Name] = i
+	}
+	for _, c := range configured {
+		i, known := idx[c.Name]
+		switch {
+		case known && c.Expr == "":
+			out[i] = patchRule(out[i], c)
+		case known:
+			out[i] = c
+		default:
+			idx[c.Name] = len(out)
+			out = append(out, c)
+		}
+	}
+	for _, r := range out {
+		if err := r.Validate(); err != nil {
+			return nil, err
+		}
+	}
+	return out, nil
+}
+
+const (
+	ramRE    = `(?i).*(physical memory|(^|[^a-z])ram([^a-z]|$)).*`
+	notDiskE = `(?i).*(memory|swap|buffers|cached|(^|[^a-z])ram([^a-z]|$)).*`
+)
+
+// DefaultRules returns the shipped rules. Notes on the less obvious queries:
+//
+//   - Every gauge is wrapped in last_over_time over a window of at least three
+//     poll intervals, so a 5 min poll does not fall out of the store's default
+//     5 min lookback and read as "no data".
+//   - interface_errors: error ratio in percent. Packets are rate of
+//     ifHCIn/OutUcastPkts when the device exports them, else
+//     (ifHCInOctets+ifHCOutOctets)/1500 (the shipped profiles carry no packet
+//     counters, so the approximation is the usual path and understates packets
+//     for small-packet traffic, which only makes the alert earlier). The
+//     denominator is floored at 10 pkt/s so an idle port with a single error
+//     does not read as 100% (and a zero denominator never yields NaN).
+//   - memory_high: UCD memAvailReal/memTotalReal when present, else the
+//     hrStorage rows whose component (hrStorageDescr) matches /physical memory|ram/i.
+//     hrStorageType is not a label, so the description is all there is. UCD
+//     "available" excludes cache, so it reads high on Linux; that is the
+//     conventional reading.
+//   - disk_full: every hrStorage row that is not memory, swap, buffers or cache.
+//     The value is max(used%, 100 if predict_linear over 6 h reaches the size
+//     within 24 h; tagged kind=predicted so union keeps both), so one threshold covers both conditions; a threshold of 100
+//     or more disables the prediction half in effect.
+//   - printer_supply_low: negative levels (-1 other, -2 unknown, -3 "some
+//     remaining") are filtered out; the series then goes stale rather than low.
+//   - temp_high: the temperature metrics of the shipped profiles, each tagged
+//     with its metric name as component where the profile has no component
+//     label. entPhySensorValue is excluded, since it mixes units. Per-profile
+//     thresholds arrive through Options.ThresholdFor; the default is 70.
+func DefaultRules() []Rule {
+	lab := func(l ...string) []string { return l }
+	return append(hostRules(lab), deviceRules(lab)...)
+}
+
+// hostRules are the interface, CPU, memory and disk rules of DefaultRules.
+func hostRules(lab func(...string) []string) []Rule {
+	return []Rule{
+		{
+			Name: "interface_down", Severity: SevWarning, Op: OpGreater, Threshold: 0, For: 2 * time.Minute,
+			Labels:      lab("device", "iface"),
+			Expr:        `(ifOperStatus == bool 2) * on(device, iface) (ifAdminStatus == bool 1)`,
+			Summary:     `{{.Device}} interface {{.Iface}} is down`,
+			Description: `Interface {{.Iface}} on {{.Device}} is operationally down while administratively up (for {{.For}}).`,
+		},
+		{
+			Name: "interface_errors", Severity: SevWarning, Op: OpGreater, Threshold: 0.1, For: 0,
+			Labels: lab("device", "iface"), SkipUnreliable: true,
+			Expr: `100 * (rate(ifInErrors[5m]) + rate(ifOutErrors[5m])) / clamp_min(` +
+				`(rate(ifHCInUcastPkts[5m]) + rate(ifHCOutUcastPkts[5m])) or ` +
+				`((rate(ifHCInOctets[5m]) + rate(ifHCOutOctets[5m])) / 1500), 10)`,
+			Summary: `{{.Device}} interface {{.Iface}} error ratio {{printf "%.2f" .Value}}%`,
+			Description: `Errors are {{printf "%.2f" .Value}}% of packets over 5 minutes on {{.Iface}} of {{.Device}} ` +
+				`(threshold {{printf "%.2f" .Threshold}}%).`,
+		},
+		{
+			Name: "cpu_high", Severity: SevWarning, Op: OpGreater, Threshold: 90, For: 10 * time.Minute,
+			Labels:      lab("device"),
+			Expr:        `avg by (device) (last_over_time(hrProcessorLoad[15m]))`,
+			Summary:     `{{.Device}} CPU at {{printf "%.0f" .Value}}%`,
+			Description: `Average processor load on {{.Device}} is {{printf "%.1f" .Value}}% (threshold {{printf "%.0f" .Threshold}}%).`,
+		},
+		{
+			Name: "memory_high", Severity: SevWarning, Op: OpGreater, Threshold: 90, For: 10 * time.Minute,
+			Labels: lab("device"),
+			Expr: `(100 * (1 - last_over_time(memAvailReal[15m]) / (last_over_time(memTotalReal[15m]) > 0))) or on(device) ` +
+				`(max by (device) (100 * last_over_time(hrStorageUsed{component=~"` + ramRE + `"}[15m]) / ` +
+				`(last_over_time(hrStorageSize{component=~"` + ramRE + `"}[15m]) > 0)))`,
+			Summary:     `{{.Device}} memory at {{printf "%.0f" .Value}}%`,
+			Description: `Memory use on {{.Device}} is {{printf "%.1f" .Value}}% (threshold {{printf "%.0f" .Threshold}}%).`,
+		},
+		{
+			Name: "disk_full", Severity: SevCritical, Op: OpGreater, Threshold: 90, For: 0,
+			Labels: lab("device", "component"),
+			Expr: `max by (device, component) (union(` +
+				`100 * last_over_time(hrStorageUsed{component!~"` + notDiskE + `"}[15m]) / ` +
+				`(last_over_time(hrStorageSize{component!~"` + notDiskE + `"}[15m]) > 0), ` +
+				`label_set(100 * (predict_linear(hrStorageUsed{component!~"` + notDiskE + `"}[6h], 86400) > bool ` +
+				`last_over_time(hrStorageSize{component!~"` + notDiskE + `"}[15m])), "kind", "predicted")))`,
+			Summary: `{{.Device}} {{.Component}} is {{printf "%.0f" .Value}}% full or filling`,
+			Description: `Storage {{.Component}} on {{.Device}} is above {{printf "%.0f" .Threshold}}% used or ` +
+				`predicted to fill within 24 hours (value {{printf "%.1f" .Value}}).`,
+		},
+	}
+}
+
+// deviceRules are the UPS, printer and temperature rules of DefaultRules.
+func deviceRules(lab func(...string) []string) []Rule {
+	return []Rule{
+		{
+			Name: "ups_on_battery", Severity: SevCritical, Op: OpGreater, Threshold: 0, For: 0,
+			Labels:      lab("device"),
+			Expr:        `max by (device) (last_over_time(upsOutputSource[15m]) == bool 5)`,
+			Summary:     `{{.Device}} UPS is on battery`,
+			Description: `The UPS {{.Device}} reports its output source as battery.`,
+		},
+		{
+			Name: "ups_runtime_low", Severity: SevCritical, Op: OpLess, Threshold: 10, For: time.Minute,
+			Labels: lab("device"),
+			Expr: `min by (device) (last_over_time(upsEstimatedMinutesRemaining[15m])) or on(device) ` +
+				`min by (device) (last_over_time(upsAdvBatteryRunTimeRemaining[15m]) / 60)`,
+			Summary:     `{{.Device}} UPS runtime {{printf "%.0f" .Value}} min`,
+			Description: `The UPS {{.Device}} estimates {{printf "%.1f" .Value}} minutes of runtime (threshold {{printf "%.0f" .Threshold}}).`,
+		},
+		{
+			Name: "printer_supply_low", Severity: SevWarning, Op: OpLess, Threshold: 10, For: 0,
+			Labels: lab("device", "component"),
+			Expr: `100 * (last_over_time(prtMarkerSuppliesLevel[1h]) >= 0) / ` +
+				`(last_over_time(prtMarkerSuppliesMaxCapacity[1h]) > 0)`,
+			Summary:     `{{.Device}} {{.Component}} at {{printf "%.0f" .Value}}%`,
+			Description: `Supply {{.Component}} on {{.Device}} is at {{printf "%.0f" .Value}}% (threshold {{printf "%.0f" .Threshold}}%).`,
+		},
+		{
+			Name: "temp_high", Severity: SevWarning, Op: OpGreater, Threshold: 70, For: 5 * time.Minute,
+			Labels: lab("device", "component"),
+			Expr: `union(` +
+				`label_set(last_over_time(mtxrHlTemperature[15m]), "component", "mtxrHlTemperature"), ` +
+				`label_set(last_over_time(mtxrHlProcessorTemperature[15m]), "component", "mtxrHlProcessorTemperature"), ` +
+				`label_set(last_over_time(upsAdvBatteryTemperature[15m]), "component", "upsAdvBatteryTemperature"), ` +
+				`last_over_time(jnxOperatingTemp[15m]))`,
+			Summary:     `{{.Device}} {{.Component}} at {{printf "%.0f" .Value}} C`,
+			Description: `Temperature {{.Component}} on {{.Device}} is {{printf "%.1f" .Value}} C (threshold {{printf "%.0f" .Threshold}}).`,
+		},
+	}
+}

internal/alert/state.go

@@ -0,0 +1,241 @@
+package alert
+
+import (
+	"context"
+	"encoding/json"
+	"time"
+
+	"github.com/v10networks/nmon/internal/store"
+)
+
+func (ev *Evaluator) save(ctx context.Context, a *store.Alert) bool {
+	if err := ev.o.Store.UpsertAlertState(ctx, a); err != nil {
+		ev.log.Error("persist alert state", "rule", a.Rule, "key", a.SeriesKey, "err", err)
+		return false
+	}
+	return true
+}
+
+func tptr(t time.Time) *time.Time { return &t }
+
+// apply handles one reading (below or above) for an entity; a is its active row or nil.
+func (ev *Evaluator) apply(ctx context.Context, now time.Time, r *compiledRule, rd reading, thr float64, a *store.Alert) {
+	ent := rd.ent
+	breach := r.breach(rd.value, thr)
+	if a != nil && ev.flapExpired(now, a) {
+		ev.exitFlap(now, a)
+		if a.State == store.AlertResolved { // closed by the flap exit; this reading starts afresh
+			ev.finish(ctx, now, r, a, ent, rd.value, thr)
+			a = nil
+		}
+	}
+	if a == nil {
+		if !breach {
+			return
+		}
+		a = ev.newPending(ctx, now, r, ent)
+	}
+	a.NodataCount = 0
+	ev.clearStale(now, a)
+	if a.PendingSince == nil {
+		a.PendingSince = tptr(now)
+	}
+	if !ev.advance(ctx, now, r, a, breach) {
+		return
+	}
+	ev.finish(ctx, now, r, a, ent, rd.value, thr)
+}
+
+// newPending starts an incident row for ent, inheriting its flap history.
+func (ev *Evaluator) newPending(ctx context.Context, now time.Time, r *compiledRule, ent Entity) *store.Alert {
+	a := &store.Alert{
+		Rule: r.Name, SeriesKey: ent.Key(), DeviceSlug: ent.Device, Iface: ent.Iface, Component: ent.Component,
+		Severity: r.Severity, State: store.AlertPending, BaseState: store.AlertPending, PendingSince: tptr(now),
+		FlapChanges: "[]",
+	}
+	// Flap history survives across incident rows.
+	if prev, err := ev.o.Store.LatestAlertBySeries(ctx, a.SeriesKey); err == nil {
+		a.FlapChanges = prev.FlapChanges
+	}
+	return a
+}
+
+// clearStale lets a real reading take a stale row back to its prior state.
+func (ev *Evaluator) clearStale(now time.Time, a *store.Alert) {
+	if a.BaseState != store.AlertStale {
+		return
+	}
+	a.BaseState = a.PriorState
+	a.PriorState = ""
+	if a.BaseState == store.AlertPending {
+		a.PendingSince = tptr(now) // the old timer spans a gap we cannot vouch for
+	}
+	if !ev.inFlap(now, a) {
+		a.State = a.BaseState
+	}
+}
+
+// advance moves the row's base state according to the reading. It reports
+// false when the row was dropped and there is nothing to persist.
+func (ev *Evaluator) advance(ctx context.Context, now time.Time, r *compiledRule, a *store.Alert, breach bool) bool {
+	switch a.BaseState {
+	case store.AlertPending:
+		return ev.advancePending(ctx, now, r, a, breach)
+	case store.AlertFiring:
+		if !breach {
+			ev.resolve(now, a)
+		}
+	case store.AlertResolved: // only inside a flapping period
+		if breach {
+			a.BaseState, a.PendingSince, a.ClearedAt = store.AlertPending, tptr(now), nil
+			if r.For <= 0 {
+				ev.fire(now, a)
+			}
+		}
+	}
+	return true
+}
+
+func (ev *Evaluator) advancePending(ctx context.Context, now time.Time, r *compiledRule, a *store.Alert, breach bool) bool {
+	switch {
+	case !breach && !ev.inFlap(now, a):
+		if a.ID != 0 {
+			if err := ev.o.Store.DeletePendingAlert(ctx, a.ID); err != nil {
+				ev.log.Error("drop pending alert", "err", err)
+			}
+		}
+		return false // never fired: nothing to keep
+	case !breach:
+		a.BaseState = store.AlertResolved
+		a.ClearedAt = tptr(now)
+	case now.Sub(*a.PendingSince) >= r.For:
+		ev.fire(now, a)
+	}
+	return true
+}
+
+// finish refreshes the descriptive columns, persists and delivers.
+func (ev *Evaluator) finish(ctx context.Context, now time.Time, r *compiledRule, a *store.Alert, ent Entity, v, thr float64) {
+	a.Value, a.Threshold, a.LastEvalAt = v, thr, tptr(now)
+	data := TemplateData{Rule: r.Name, Severity: r.Severity, Device: ent.Device, Iface: ent.Iface, Component: ent.Component,
+		Value: v, Threshold: thr, Op: r.Op, For: r.For}
+	a.Summary, a.Description = r.render(r.summary, data), r.render(r.desc, data)
+	ev.persistAndDeliver(ctx, now, a, ent)
+}
+
+func (ev *Evaluator) persistAndDeliver(ctx context.Context, now time.Time, a *store.Alert, ent Entity) {
+	if !ev.save(ctx, a) {
+		return
+	}
+	ev.deliver(ctx, now, a, ent)
+}
+
+func (ev *Evaluator) fire(now time.Time, a *store.Alert) {
+	a.BaseState = store.AlertFiring
+	a.ClearedAt = nil
+	if a.FiredAt == nil {
+		a.FiredAt = tptr(now)
+	}
+	ev.changed(now, a, NotifyFiring)
+}
+
+func (ev *Evaluator) resolve(now time.Time, a *store.Alert) {
+	a.BaseState = store.AlertResolved
+	a.ClearedAt = tptr(now)
+	ev.changed(now, a, NotifyResolved)
+}
+
+// changed records a firing/resolved change: it sets the visible state, counts
+// it for flap damping and chooses the notification (flapping replaces the
+// change that tipped the count over).
+func (ev *Evaluator) changed(now time.Time, a *store.Alert, notify string) {
+	if ev.inFlap(now, a) {
+		a.State = store.AlertFlapping
+		return // silent while flapping
+	}
+	times := parseChanges(a.FlapChanges)
+	cut := now.Add(-FlapWindow).UnixMilli()
+	kept := times[:0]
+	for _, t := range times {
+		if t > cut {
+			kept = append(kept, t)
+		}
+	}
+	kept = append(kept, now.UnixMilli())
+	if len(kept) > FlapMax {
+		a.State = store.AlertFlapping
+		a.FlappingUntil = tptr(now.Add(FlapHold))
+		a.NotifyPending = NotifyFlapping
+	} else {
+		a.State = a.BaseState
+		a.NotifyPending = notify
+	}
+	a.FlapChanges = encodeChanges(kept)
+}
+
+func parseChanges(s string) []int64 {
+	var t []int64
+	_ = json.Unmarshal([]byte(s), &t)
+	return t
+}
+
+func encodeChanges(t []int64) string {
+	b, _ := json.Marshal(t)
+	return string(b)
+}
+
+func (ev *Evaluator) inFlap(now time.Time, a *store.Alert) bool {
+	return a.FlappingUntil != nil && now.Before(*a.FlappingUntil)
+}
+
+func (ev *Evaluator) flapExpired(now time.Time, a *store.Alert) bool {
+	return a.FlappingUntil != nil && !now.Before(*a.FlappingUntil)
+}
+
+// exitFlap ends a flapping period: the row takes its underlying state and one
+// notification with that state goes out (a pending or resolved base reads as
+// resolved, since nothing is firing).
+func (ev *Evaluator) exitFlap(now time.Time, a *store.Alert) {
+	a.FlappingUntil = nil
+	a.FlapChanges = "[]"
+	switch a.BaseState {
+	case store.AlertFiring:
+		a.State = store.AlertFiring
+		a.NotifyPending = NotifyFiring
+	default:
+		a.BaseState, a.State = store.AlertResolved, store.AlertResolved
+		if a.ClearedAt == nil {
+			a.ClearedAt = tptr(now)
+		}
+		a.PendingSince = nil
+		a.NotifyPending = NotifyResolved
+	}
+}
+
+// nodata handles an active row whose series was absent from a successful query.
+func (ev *Evaluator) nodata(ctx context.Context, now time.Time, r *compiledRule, a *store.Alert) {
+	ent := entityOf(a)
+	if ev.flapExpired(now, a) {
+		ev.exitFlap(now, a)
+		ev.persistAndDeliver(ctx, now, a, ent)
+		if !isActive(a.State) {
+			return
+		}
+	}
+	a.NodataCount++
+	a.LastEvalAt = tptr(now)
+	if a.NodataCount >= StaleAfter && a.BaseState != store.AlertStale && a.State != store.AlertFlapping {
+		a.PriorState = a.BaseState
+		a.BaseState, a.State = store.AlertStale, store.AlertStale
+		a.NotifyPending = NotifyStale
+	}
+	ev.persistAndDeliver(ctx, now, a, ent)
+}
+
+// retire closes a row for a device, interface or rule that no longer exists.
+// It is not a resolution and sends nothing.
+func (ev *Evaluator) retire(ctx context.Context, now time.Time, a *store.Alert) {
+	a.State, a.BaseState, a.PriorState = store.AlertRetired, store.AlertRetired, ""
+	a.ClearedAt, a.NotifyPending, a.FlappingUntil = tptr(now), "", nil
+	ev.save(ctx, a)
+}

internal/api/admit.go

@@ -0,0 +1,99 @@
+package api
+
+import (
+	"context"
+	"net"
+	"sync"
+	"time"
+
+	"github.com/danielgtaylor/huma/v2"
+)
+
+// admission keeps metric-store query load bounded: a per-client cap on
+// free-form queries (so one dashboard cannot starve the rest) and a global
+// semaphore on every store query (so the UI cannot crowd out the poll path).
+// A request over its client cap is refused at once; one waiting for a global
+// slot waits up to wait, then is refused. Both are 429 problems.
+type admission struct {
+	global    chan struct{}
+	perClient int
+	wait      time.Duration
+
+	mu     sync.Mutex
+	active map[string]int
+}
+
+func newAdmission(perClient, global int, wait time.Duration) *admission {
+	return &admission{global: make(chan struct{}, global), perClient: perClient, wait: wait, active: map[string]int{}}
+}
+
+// clientKey carries the caller's identity from the middleware to the handlers.
+// Until authentication exists (M6) it is the remote address without the port.
+type clientKey struct{}
+
+func clientKeyMiddleware(ctx huma.Context, next func(huma.Context)) {
+	host, _, err := net.SplitHostPort(ctx.RemoteAddr())
+	if err != nil {
+		host = ctx.RemoteAddr()
+	}
+	next(huma.WithValue(ctx, clientKey{}, host))
+}
+
+func clientOf(ctx context.Context) string {
+	c, _ := ctx.Value(clientKey{}).(string)
+	return c
+}
+
+func tooMany(msg string) error {
+	return huma.Error429TooManyRequests(msg)
+}
+
+// acquire admits one query. freeForm queries also count against the client's cap.
+// The returned release must be called exactly once.
+func (a *admission) acquire(ctx context.Context, freeForm bool) (release func(), err error) {
+	client := clientOf(ctx)
+	if freeForm && !a.takeClient(client) {
+		return nil, tooMany("too many concurrent queries from " + client + "; the limit is " + itoa(a.perClient))
+	}
+	wctx, cancel := context.WithTimeout(ctx, a.wait)
+	defer cancel()
+	select {
+	case a.global <- struct{}{}:
+	case <-wctx.Done():
+		if freeForm {
+			a.dropClient(client)
+		}
+		return nil, tooMany("the metric store is busy; try again shortly")
+	}
+	return func() {
+		<-a.global
+		if freeForm {
+			a.dropClient(client)
+		}
+	}, nil
+}
+
+func (a *admission) takeClient(client string) bool {
+	a.mu.Lock()
+	defer a.mu.Unlock()
+	if a.active[client] >= a.perClient {
+		return false
+	}
+	a.active[client]++
+	return true
+}
+
+func (a *admission) dropClient(client string) {
+	a.mu.Lock()
+	defer a.mu.Unlock()
+	if a.active[client] <= 1 {
+		delete(a.active, client)
+		return
+	}
+	a.active[client]--
+}
+
+// admit takes a query slot for the request in ctx.
+func (s *server) admit(ctx context.Context, freeForm bool) (func(), error) {
+	return s.adm.acquire(ctx, freeForm)
+}

internal/api/api.go

@@ -3,6 +3,7 @@
 package api
 
 import (
+	"cmp"
 	"context"
 	"encoding/json"
 	"errors"
@@ -16,6 +17,8 @@ import (
 	"github.com/danielgtaylor/huma/v2/adapters/humago"
 
 	"github.com/v10networks/nmon/internal/clock"
+	"github.com/v10networks/nmon/internal/poller"
+	"github.com/v10networks/nmon/internal/profile"
 	"github.com/v10networks/nmon/internal/selfmon"
 	"github.com/v10networks/nmon/internal/store"
 )
@@ -30,6 +33,8 @@ const (
 	MaxSeries = 100_000
 	// DiscoveryTimeout bounds the seed discovery run by POST /devices.
 	DiscoveryTimeout = 30 * time.Second
+	// Version is the API's OpenAPI info.version; it changes only with the route contract, never with a build.
+	Version = "1.0.0"
 )
 
 // Querier runs read-only MetricsQL against the hot store. *vmsup.Querier implements it.
@@ -50,17 +55,43 @@ type Deps struct {
 	Registry *selfmon.Registry // served at /metrics; default selfmon.Default
 	Logger   *slog.Logger      // default slog.Default()
 	SNMPPort int               // dev/test override of UDP 161; 0 = 161
+	// Profiles select a device's profile at seed discovery. Nil: no profile matching.
+	Profiles *profile.Set
+
+	// PollerStatus feeds GET /poller/health. *poller.Poller's Status fits.
+	PollerStatus func() []poller.DeviceStatus
+	// AfterDiscover is called after POST /devices/{slug}/discover succeeded, e.g. to make the poller reload that device.
+	AfterDiscover func(deviceID int64)
 
 	// DiscoveryTimeout overrides the 30 s seed discovery limit (tests).
 	DiscoveryTimeout time.Duration
+
+	// Reachability decides up/down/warning per device. Default: what is persisted now
+	// (poll state, last_seen, the ICMP and SNMP up series). M4 swaps in the alerter's state.
+	Reachability ReachabilitySource
+	// PollInterval is the normal poll cadence; a device unheard of for three of them is down. Default 60 s.
+	PollInterval time.Duration
+
+	// HotRetention, FiveMinuteRetention and LongRetention are the stores' retention periods. They decide where a
+	// graph stitches and what GET /meta reports. Defaults: 30 d, 120 d, 2 y.
+	HotRetention, FiveMinuteRetention, LongRetention time.Duration
+	// WriteQueueCapacity is the hot write queue's size in samples, for GET /poller/health. Default 2,000,000.
+	WriteQueueCapacity int
+
+	// MaxClientQueries and MaxGlobalQueries bound concurrent free-form queries per client and metric-store
+	// queries overall (defaults 4 and 16). AdmissionWait is how long a request waits for a global slot (default 5 s).
+	MaxClientQueries, MaxGlobalQueries int
+	AdmissionWait                      time.Duration
 }
 
 type server struct {
 	Deps
+	adm  *admission
+	rate *counterRates
 }
 
-// New returns the API handler with every route registered.
-func New(d Deps) http.Handler {
+// withDefaults fills every unset optional dependency.
+func (d Deps) withDefaults() Deps {
 	if d.Clock == nil {
 		d.Clock = clock.Real()
 	}
@@ -70,24 +101,72 @@ func New(d Deps) http.Handler {
 	if d.Logger == nil {
 		d.Logger = slog.Default()
 	}
-	if d.DiscoveryTimeout <= 0 {
-		d.DiscoveryTimeout = DiscoveryTimeout
+	d.DiscoveryTimeout = cmp.Or(d.DiscoveryTimeout, DiscoveryTimeout)
+	d.PollInterval = cmp.Or(d.PollInterval, time.Minute)
+	d.HotRetention = cmp.Or(d.HotRetention, 30*day)
+	d.FiveMinuteRetention = cmp.Or(d.FiveMinuteRetention, 120*day)
+	d.LongRetention = cmp.Or(d.LongRetention, 2*365*day)
+	d.WriteQueueCapacity = cmp.Or(d.WriteQueueCapacity, 2_000_000)
+	d.MaxClientQueries = cmp.Or(d.MaxClientQueries, 4)
+	d.MaxGlobalQueries = cmp.Or(d.MaxGlobalQueries, 16)
+	d.AdmissionWait = cmp.Or(d.AdmissionWait, 5*time.Second)
+	if d.Reachability == nil {
+		d.Reachability = &persistedReachability{q: d.Querier, clk: d.Clock, interval: d.PollInterval}
 	}
-	s := &server{d}
+	return d
+}
 
+const day = 24 * time.Hour
+
+// New returns the API handler with every route registered.
+func New(d Deps) http.Handler {
+	d = d.withDefaults()
+	s := &server{Deps: d, adm: newAdmission(d.MaxClientQueries, d.MaxGlobalQueries, d.AdmissionWait), rate: &counterRates{}}
+	s.rate.perMinute(s.readCounters()) // baseline, so the first poller/health call has a window to measure
 	mux := http.NewServeMux()
-	cfg := huma.DefaultConfig("nmon", "1.0.0")
+	api := s.newHuma(mux)
+	registerDocs(mux)
+	s.register(api)
+	return problemFallback(mux)
+}
+
+// Spec returns the OpenAPI 3.1 document of the API as indented JSON. It is the
+// same document served at /openapi.json, generated without any dependencies:
+// `nmon openapi > openapi.json` checks it in.
+func Spec() ([]byte, error) {
+	s := &server{Deps: Deps{}.withDefaults()}
+	api := s.newHuma(http.NewServeMux())
+	s.register(api)
+	return json.MarshalIndent(api.OpenAPI(), "", "  ")
+}
+
+// register adds every operation to api.
+func (s *server) register(api huma.API) {
+	s.registerDevices(api)
+	s.registerDeviceList(api)
+	s.registerDeviceViews(api)
+	s.registerInterfaces(api)
+	s.registerGraph(api)
+	s.registerOps(api)
+	s.registerHealth(api)
+	s.registerReviews(api)
+	s.registerQuery(api)
+	s.registerMeta(api)
+	s.registerMetrics(api)
+}
+
+// newHuma builds the huma API on mux. /docs is served by registerDocs from embedded assets, not huma's CDN page.
+func (s *server) newHuma(mux *http.ServeMux) huma.API {
+	configureHuma()
+	cfg := huma.DefaultConfig("nmon", Version)
 	cfg.Info.Description = "nmon network monitor API."
 	cfg.OpenAPIPath = "/openapi"
-	cfg.DocsPath = "/docs"
-	cfg.DocsRenderer = huma.DocsRendererSwaggerUI
+	cfg.DocsPath = ""
 	cfg.CreateHooks = nil // no $schema fields or Link headers in responses
+	cfg.OnAddOperation = append(cfg.OnAddOperation, addDefaultProblem)
 	api := humago.New(mux, cfg)
-
-	s.registerDevices(api)
-	s.registerQuery(api)
-	s.registerMetrics(api)
-	return problemFallback(mux)
+	api.UseMiddleware(clientKeyMiddleware)
+	return api
 }
 
 // storeErr maps store sentinels to problem responses; anything else is a 500

internal/api/api_test.go

@@ -9,6 +9,7 @@ import (
 	"net/http"
 	"net/http/httptest"
 	"strings"
+	"sync"
 	"sync/atomic"
 	"testing"
 	"time"
@@ -16,6 +17,7 @@ import (
 	"github.com/v10networks/nmon/internal/api"
 	"github.com/v10networks/nmon/internal/clock"
 	"github.com/v10networks/nmon/internal/fixturegen"
+	"github.com/v10networks/nmon/internal/poller"
 	"github.com/v10networks/nmon/internal/selfmon"
 	"github.com/v10networks/nmon/internal/simagent"
 	"github.com/v10networks/nmon/internal/store"
@@ -24,25 +26,57 @@ import (
 	"github.com/v10networks/nmon/internal/vmsup"
 )
 
+// querier is the fake metric store. fn, when set, answers every query;
+// otherwise body does. Every query is recorded.
 type querier struct {
+	mu                sync.Mutex
 	body              []byte
 	err               error
+	fn                func(store, expr string, from, to time.Time, step time.Duration) ([]byte, error)
 	q                 string
 	ts, from, to      time.Time
 	step              time.Duration
 	instant, rangeCnt int
+	calls             []call
+}
+
+type call struct {
+	store, expr string
+	from, to    time.Time
+	step        time.Duration
 }
 
 func (q *querier) Query(_ context.Context, st, expr string, ts time.Time) ([]byte, error) {
+	q.mu.Lock()
 	q.instant++
 	q.q, q.ts = expr, ts
-	return q.body, q.err
+	q.calls = append(q.calls, call{store: st, expr: expr, from: ts, to: ts})
+	fn, body, err := q.fn, q.body, q.err
+	q.mu.Unlock()
+	if fn != nil {
+		return fn(st, expr, ts, ts, 0)
+	}
+	return body, err
 }
 
 func (q *querier) QueryRange(_ context.Context, st, expr string, from, to time.Time, step time.Duration) ([]byte, error) {
+	q.mu.Lock()
 	q.rangeCnt++
 	q.q, q.from, q.to, q.step = expr, from, to, step
-	return q.body, q.err
+	q.calls = append(q.calls, call{store: st, expr: expr, from: from, to: to, step: step})
+	fn, body, err := q.fn, q.body, q.err
+	q.mu.Unlock()
+	if fn != nil {
+		return fn(st, expr, from, to, step)
+	}
+	return body, err
+}
+
+// queries returns a copy of the recorded queries.
+func (q *querier) queries() []call {
+	q.mu.Lock()
+	defer q.mu.Unlock()
+	return append([]call(nil), q.calls...)
 }
 
 type refresher struct{ n atomic.Int32 }
@@ -50,19 +84,32 @@ type refresher struct{ n atomic.Int32 }
 func (r *refresher) Refresh() { r.n.Add(1) }
 
 type env struct {
+	clk *clock.Fake
 	h   http.Handler
 	st  store.Store
 	q   *querier
 	ref *refresher
 	reg *selfmon.Registry
+
+	afterID atomic.Int64
+	status  []poller.DeviceStatus
 }
 
-func newEnv(t *testing.T, port int) *env {
+func newEnv(t *testing.T, port int) *env { return newEnvDeps(t, port, nil) }
+
+// newEnvDeps is newEnv with a chance to change the API's dependencies.
+func newEnvDeps(t *testing.T, port int, mutate func(*api.Deps)) *env {
 	clk := clock.NewFake(time.Date(2026, 10, 22, 12, 0, 0, 0, time.UTC))
-	e := &env{st: testutil.OpenStore(t, clk), q: &querier{body: []byte(`{"status":"success","data":{"resultType":"vector","result":[]}}`)},
+	e := &env{clk: clk, st: testutil.OpenStore(t, clk), q: &querier{body: []byte(`{"status":"success","data":{"resultType":"vector","result":[]}}`)},
 		ref: &refresher{}, reg: selfmon.New()}
-	e.h = api.New(api.Deps{Store: e.st, Querier: e.q, Poller: e.ref, Clock: clk, Registry: e.reg, SNMPPort: port,
-		DiscoveryTimeout: 3 * time.Second})
+	d := api.Deps{Store: e.st, Querier: e.q, Poller: e.ref, Clock: clk, Registry: e.reg, SNMPPort: port,
+		DiscoveryTimeout: 3 * time.Second,
+		PollerStatus:     func() []poller.DeviceStatus { return e.status },
+		AfterDiscover:    func(id int64) { e.afterID.Store(id) }}
+	if mutate != nil {
+		mutate(&d)
+	}
+	e.h = api.New(d)
 	return e
 }
 
@@ -270,3 +317,24 @@ func TestQueryProxy(t *testing.T) {
 	e.q.err = errors.New("connection reset")
 	isProblem(t, e.do("GET", "/api/v1/query?q=x", ""), 502)
 }
+
+func TestDocsAreSelfHosted(t *testing.T) {
+	e := newEnv(t, 0)
+	page := e.do("GET", "/docs", "")
+	if page.Code != 200 || strings.Contains(page.Body.String(), "http") && strings.Contains(page.Body.String(), "unpkg") ||
+		!strings.Contains(page.Body.String(), "/docs/assets/swagger-ui-bundle.js") {
+		t.Fatalf("/docs: %d %s", page.Code, page.Body)
+	}
+	for path, ct := range map[string]string{"/docs/assets/swagger-ui-bundle.js": "javascript", "/docs/assets/swagger-ui.css": "css", "/docs/assets/init.js": "javascript"} {
+		rec := e.do("GET", path, "")
+		if rec.Code != 200 || rec.Body.Len() < 50 || !strings.Contains(rec.Header().Get("Content-Type"), ct) {
+			t.Errorf("%s: %d %s %d bytes", path, rec.Code, rec.Header().Get("Content-Type"), rec.Body.Len())
+		}
+	}
+	if !strings.Contains(e.do("GET", "/docs/assets/init.js", "").Body.String(), "/openapi.json") {
+		t.Error("the page must load the spec from this server")
+	}
+	if rec := e.do("GET", "/openapi.json", ""); rec.Code != 200 || !strings.Contains(rec.Body.String(), `"openapi":"3.1.0"`) {
+		t.Errorf("openapi.json: %d", rec.Code)
+	}
+}

internal/api/contract_test.go

@@ -0,0 +1,435 @@
+package api_test
+
+import (
+	"encoding/json"
+	"fmt"
+	"os"
+	"slices"
+	"sort"
+	"strings"
+	"testing"
+
+	"github.com/v10networks/nmon/internal/api"
+)
+
+// The UI is built against web/openapi.contract.json. These tests hold the
+// generated OpenAPI document to it: every path, method, parameter, request
+// body and response field of the contract must exist in the generated spec
+// with a compatible type. Additions in the generated spec are fine.
+
+type obj = map[string]any
+
+// knownDivergences are places where the generated spec deliberately differs
+// from the hand-written contract. Each has a reason; anything else is a failure.
+var knownDivergences = map[string]string{
+	// M1/M2 shipped these two as strings that also accept Unix seconds and "30s"; the routes are frozen once shipped
+	// and the UI does not call them.
+	"param GET /api/v1/query_range step: type":   "frozen since M1: accepts 30s and plain seconds",
+	"param GET /api/v1/query_range from: format": "frozen since M1: accepts RFC 3339 and Unix seconds",
+	"param GET /api/v1/query_range to: format":   "frozen since M1: accepts RFC 3339 and Unix seconds",
+	"param GET /api/v1/query time: format":       "frozen since M1: accepts RFC 3339 and Unix seconds",
+	// The contract left q optional; an empty expression is meaningless, so the API requires it.
+	"param GET /api/v1/query q: required":          "q is required by the frozen M1 route",
+	"param GET /api/v1/query_range q: required":    "q is required by the frozen M1 route",
+	"param GET /api/v1/query_range step: required": "step is required by the frozen M1 route",
+}
+
+type checker struct {
+	t      *testing.T
+	gen    obj
+	con    obj
+	failed []string
+}
+
+func (c *checker) fail(key, format string, a ...any) {
+	if _, ok := knownDivergences[key]; ok {
+		return
+	}
+	c.failed = append(c.failed, fmt.Sprintf("%s: %s", key, fmt.Sprintf(format, a...)))
+}
+
+func load(t *testing.T) *checker {
+	t.Helper()
+	raw, err := os.ReadFile("../../web/openapi.contract.json")
+	if err != nil {
+		t.Fatal(err)
+	}
+	var con obj
+	if err := json.Unmarshal(raw, &con); err != nil {
+		t.Fatal(err)
+	}
+	spec, err := api.Spec()
+	if err != nil {
+		t.Fatal(err)
+	}
+	var gen obj
+	if err := json.Unmarshal(spec, &gen); err != nil {
+		t.Fatal(err)
+	}
+	return &checker{t: t, gen: gen, con: con}
+}
+
+func get(m any, keys ...string) any {
+	for _, k := range keys {
+		mm, ok := m.(obj)
+		if !ok {
+			return nil
+		}
+		m = mm[k]
+	}
+	return m
+}
+
+// resolve follows $ref within doc.
+func resolve(doc obj, s any) obj {
+	m, _ := s.(obj)
+	for m != nil {
+		ref, ok := m["$ref"].(string)
+		if !ok {
+			return m
+		}
+		m, _ = get(doc, strings.Split(strings.TrimPrefix(ref, "#/"), "/")...).(obj)
+	}
+	return nil
+}
+
+// shape is a schema reduced to what the comparison needs.
+type shape struct {
+	typ      string
+	nullable bool
+	s        obj
+}
+
+func shapeOf(doc obj, raw any) shape {
+	s := resolve(doc, raw)
+	sh := shape{s: s}
+	switch t := s["type"].(type) {
+	case string:
+		sh.typ = t
+	case []any:
+		for _, x := range t {
+			if x == "null" {
+				sh.nullable = true
+			} else {
+				sh.typ, _ = x.(string)
+			}
+		}
+	}
+	if alts, ok := s["anyOf"].([]any); ok {
+		for _, a := range alts {
+			am := resolve(doc, a)
+			if am["type"] == "null" {
+				sh.nullable = true
+				continue
+			}
+			sub := shapeOf(doc, am)
+			sh.typ, sh.s = sub.typ, sub.s
+		}
+	}
+	return sh
+}
+
+// compat checks that gen can stand where con is expected. request flips the
+// direction of the required/nullable rules: a client sends what the contract
+// allows, and receives what the contract promises.
+func (c *checker) compat(key string, con, gen any, request bool) {
+	cs, gs := shapeOf(c.con, con), shapeOf(c.gen, gen)
+	if cs.typ != gs.typ && (cs.typ != "number" || gs.typ != "integer") {
+		c.fail(key+": type", "contract %q, generated %q", cs.typ, gs.typ)
+		return
+	}
+	if !request && cs.nullable && !gs.nullable {
+		c.fail(key+": nullable", "contract allows null, generated never sends it (fine) -- but UI types expect null; declare nullable")
+	}
+	if !request && gs.nullable && !cs.nullable {
+		c.fail(key+": nullable", "generated may send null, contract does not allow it")
+	}
+	for _, k := range []string{"format", "minimum", "maximum", "minLength", "maxLength", "minItems", "maxItems"} {
+		if cv, ok := cs.s[k]; ok && fmt.Sprint(cv) != fmt.Sprint(gs.s[k]) {
+			c.fail(key+": "+k, "contract %v, generated %v", cv, gs.s[k])
+		}
+	}
+	c.enums(key, cs.s, gs.s, request)
+	switch cs.typ {
+	case "object":
+		c.object(key, cs.s, gs.s, request)
+	case "array":
+		c.array(key, cs.s, gs.s, request)
+	}
+}
+
+func (c *checker) enums(key string, con, gen obj, request bool) {
+	ce, _ := con["enum"].([]any)
+	if len(ce) == 0 {
+		return
+	}
+	ge, _ := gen["enum"].([]any)
+	have := func(list []any, v any) bool { return slices.Contains(list, v) }
+	for _, v := range ge {
+		if !request && !have(ce, v) {
+			c.fail(key+": enum", "generated may send %v, not in the contract", v)
+		}
+	}
+	for _, v := range ce {
+		if (request || len(ge) == 0) && !have(ge, v) {
+			c.fail(key+": enum", "contract value %v missing from generated", v)
+		}
+	}
+}
+
+func (c *checker) object(key string, con, gen obj, request bool) {
+	cp, _ := con["properties"].(obj)
+	gp, _ := gen["properties"].(obj)
+	names := make([]string, 0, len(cp))
+	for n := range cp {
+		names = append(names, n)
+	}
+	sort.Strings(names)
+	for _, n := range names {
+		if _, ok := gp[n]; !ok {
+			c.fail(key+"."+n, "missing from generated")
+			continue
+		}
+		c.compat(key+"."+n, cp[n], gp[n], request)
+	}
+	creq, greq := strset(con["required"]), strset(gen["required"])
+	if request {
+		for n := range greq {
+			if !creq[n] {
+				c.fail(key+"."+n+": required", "generated requires a field the contract made optional")
+			}
+		}
+		return
+	}
+	for n := range creq {
+		if !greq[n] {
+			c.fail(key+"."+n+": required", "contract promises it, generated may omit it")
+		}
+	}
+}
+
+func strset(v any) map[string]bool {
+	out := map[string]bool{}
+	l, _ := v.([]any)
+	for _, x := range l {
+		out[fmt.Sprint(x)] = true
+	}
+	return out
+}
+
+func (c *checker) array(key string, con, gen obj, request bool) {
+	if pc, ok := con["prefixItems"].([]any); ok {
+		pg, _ := gen["prefixItems"].([]any)
+		if len(pg) != len(pc) {
+			c.fail(key+": prefixItems", "contract has %d, generated %d", len(pc), len(pg))
+			return
+		}
+		for i := range pc {
+			c.compat(fmt.Sprintf("%s[%d]", key, i), pc[i], pg[i], request)
+		}
+		return
+	}
+	if con["items"] != nil {
+		if gen["items"] == nil {
+			c.fail(key+": items", "generated array has no items schema")
+			return
+		}
+		c.compat(key+"[]", con["items"], gen["items"], request)
+	}
+}
+
+// operations lists "METHOD path" for every operation of doc, with path-level parameters merged in.
+func operations(doc obj) map[string]obj {
+	out := map[string]obj{}
+	paths, _ := doc["paths"].(obj)
+	for p, item := range paths {
+		im, _ := item.(obj)
+		for m, op := range im {
+			om, ok := op.(obj)
+			if !ok || m == "parameters" {
+				continue
+			}
+			merged := obj{}
+			for k, v := range om {
+				merged[k] = v
+			}
+			params, _ := im["parameters"].([]any)
+			merged["parameters"] = append(slices.Clone(params), asList(om["parameters"])...)
+			out[strings.ToUpper(m)+" "+p] = merged
+		}
+	}
+	return out
+}
+
+func asList(v any) []any { l, _ := v.([]any); return l }
+
+func (c *checker) params(opKey string, con, gen obj) {
+	genByName := map[string]obj{}
+	for _, p := range asList(gen["parameters"]) {
+		pm := resolve(c.gen, p)
+		genByName[fmt.Sprint(pm["in"])+" "+fmt.Sprint(pm["name"])] = pm
+	}
+	conByName := map[string]bool{}
+	for _, p := range asList(con["parameters"]) {
+		pm := resolve(c.con, p)
+		id := fmt.Sprint(pm["in"]) + " " + fmt.Sprint(pm["name"])
+		conByName[id] = true
+		key := fmt.Sprintf("param %s %s", opKey, pm["name"])
+		g, ok := genByName[id]
+		if !ok {
+			c.fail(key, "missing from generated")
+			continue
+		}
+		if pm["required"] == true && g["required"] != true {
+			c.fail(key+": required", "contract requires it, generated does not")
+		}
+		if pm["required"] != true && g["required"] == true {
+			c.fail(key+": required", "generated requires a parameter the contract made optional")
+		}
+		c.compat(key, pm["schema"], g["schema"], true)
+	}
+	for id, g := range genByName {
+		if g["required"] == true && !conByName[id] {
+			c.fail(fmt.Sprintf("param %s %s", opKey, g["name"]), "new required parameter not in the contract")
+		}
+	}
+}
+
+func (c *checker) body(opKey string, con, gen obj) {
+	cb := resolve(c.con, get(con, "requestBody"))
+	if cb == nil {
+		return
+	}
+	gb := resolve(c.gen, get(gen, "requestBody"))
+	cs, gs := get(cb, "content", "application/json", "schema"), get(gb, "content", "application/json", "schema")
+	if gs == nil {
+		c.fail("body "+opKey, "generated has no JSON request body")
+		return
+	}
+	c.compat("body "+opKey, cs, gs, true)
+}
+
+func (c *checker) responses(opKey string, con, gen obj) {
+	cr, _ := con["responses"].(obj)
+	gr, _ := gen["responses"].(obj)
+	for code, r := range cr {
+		g, ok := gr[code]
+		if !ok {
+			c.fail("response "+opKey+" "+code, "missing from generated")
+			continue
+		}
+		cm, _ := get(resolve(c.con, r), "content").(obj)
+		for ct, media := range cm {
+			gm := get(resolve(c.gen, g), "content", ct, "schema")
+			if gm == nil {
+				c.fail("response "+opKey+" "+code, "no %s content in generated", ct)
+				continue
+			}
+			c.compat(fmt.Sprintf("response %s %s", opKey, code), get(media, "schema"), gm, false)
+		}
+	}
+}
+
+func TestGeneratedSpecMatchesUIContract(t *testing.T) {
+	c := load(t)
+	if c.gen["openapi"] != "3.1.0" {
+		t.Fatalf("generated openapi version %v, want 3.1.0", c.gen["openapi"])
+	}
+	conOps, genOps := operations(c.con), operations(c.gen)
+	for key, con := range conOps {
+		gen, ok := genOps[key]
+		if !ok {
+			c.fail("operation "+key, "missing from generated spec")
+			continue
+		}
+		c.params(key, con, gen)
+		c.body(key, con, gen)
+		c.responses(key, con, gen)
+	}
+	if len(c.failed) > 0 {
+		sort.Strings(c.failed)
+		t.Fatalf("generated spec breaks the UI contract (%d):\n  %s", len(c.failed), strings.Join(c.failed, "\n  "))
+	}
+}
+
+// TestContractDivergencesStayNeeded fails when a divergence is no longer needed, so the list shrinks.
+func TestContractDivergencesStayNeeded(t *testing.T) {
+	c := load(t)
+	saved := knownDivergences
+	defer func() { knownDivergences = saved }()
+	knownDivergences = map[string]string{}
+	conOps, genOps := operations(c.con), operations(c.gen)
+	for key, con := range conOps {
+		if gen, ok := genOps[key]; ok {
+			c.params(key, con, gen)
+		}
+	}
+	hit := strings.Join(c.failed, "\n")
+	for k := range saved {
+		if !strings.Contains(hit, k) {
+			t.Errorf("divergence %q no longer happens; remove it", k)
+		}
+	}
+}
+
+// TestResponseSchemasExposeNoIDsOrCredentials walks every schema reachable from a
+// response in the generated spec: no integer id, and no credential-like property.
+func TestResponseSchemasExposeNoIDsOrCredentials(t *testing.T) {
+	c := load(t)
+	seen := map[string]bool{}
+	var walk func(path string, raw any)
+	walk = func(path string, raw any) {
+		m, _ := raw.(obj)
+		if ref, ok := m["$ref"].(string); ok {
+			if seen[ref] {
+				return
+			}
+			seen[ref] = true
+			walk(path+"→"+ref, resolve(c.gen, m))
+			return
+		}
+		props, _ := m["properties"].(obj)
+		for name, p := range props {
+			lower := strings.ToLower(name)
+			if (lower == "id" || strings.HasSuffix(lower, "_id")) && shapeOf(c.gen, p).typ != "string" {
+				t.Errorf("%s.%s is not a string id", path, name)
+			}
+			for _, bad := range []string{"community", "password", "pass", "hash", "secret", "token", "credential", "key"} {
+				if strings.Contains(lower, bad) {
+					t.Errorf("%s.%s looks like a credential", path, name)
+				}
+			}
+			walk(path+"."+name, p)
+		}
+		if items := m["items"]; items != nil {
+			walk(path+"[]", items)
+		}
+		for _, k := range []string{"anyOf", "oneOf", "allOf"} {
+			for _, a := range asList(m[k]) {
+				walk(path, a)
+			}
+		}
+	}
+	for key, op := range operations(c.gen) {
+		responses, _ := op["responses"].(obj)
+		for code, r := range responses {
+			walk(key+" "+code, get(resolve(c.gen, r), "content", "application/json", "schema"))
+		}
+	}
+}
+
+// TestCheckedInOpenAPIIsCurrent keeps openapi.json (the file the UI client is
+// generated from) equal to what the handlers produce.
+func TestCheckedInOpenAPIIsCurrent(t *testing.T) {
+	want, err := api.Spec()
+	if err != nil {
+		t.Fatal(err)
+	}
+	got, err := os.ReadFile("../../openapi.json")
+	if err != nil {
+		t.Fatal(err)
+	}
+	if strings.TrimSpace(string(got)) != strings.TrimSpace(string(want)) {
+		t.Fatal("openapi.json is stale: run `go run ./cmd/nmon openapi > openapi.json`")
+	}
+}

internal/api/detail_test.go

@@ -0,0 +1,226 @@
+package api_test
+
+import (
+	"context"
+	"encoding/json"
+	"strings"
+	"testing"
+	"time"
+
+	"github.com/v10networks/nmon/internal/api"
+	"github.com/v10networks/nmon/internal/store"
+)
+
+func TestDeviceDetailLiveRates(t *testing.T) {
+	e := newEnv(t, 0)
+	core := e.device(t, "Core", "yyz", "core", func(d *store.Device) { d.HWSerial, d.SysDescr = "SN1", "JunOS" })
+	other := e.device(t, "Other", "", "")
+	i1 := e.iface(t, core, 1, "xe-0/0/1", "up")
+	i2 := e.iface(t, core, 2, "xe-0/0/2", "32bit", func(i *store.Interface) { i.HasHCCounters = false })
+	i3 := e.iface(t, core, 3, "xe-0/0/3", "bad", func(i *store.Interface) { i.Unreliable, i.HasHCCounters = true, false })
+	i4 := e.iface(t, core, 4, "xe-0/0/4", "idle")
+	i5 := e.iface(t, core, 5, "xe-0/0/5", "gone")
+	if err := e.st.RetireInterface(t.Context(), i5.ID); err != nil {
+		t.Fatal(err)
+	}
+	if err := e.st.SetParents(t.Context(), core.ID, store.RelNetwork, []int64{other.ID}); err != nil {
+		t.Fatal(err)
+	}
+	e.q.fn = func(_, expr string, _, _ time.Time, _ time.Duration) ([]byte, error) {
+		if !strings.Contains(expr, `device="`+core.Slug+`"`) {
+			return emptyMatrix, nil
+		}
+		l := func(id, k string) map[string]string { return map[string]string{"iface": id, "k": k} }
+		return vector(
+			vrow{l(i1.ID, "in_hc"), 8e6}, vrow{l(i1.ID, "out_hc"), 4e6}, vrow{l(i1.ID, "in_err"), 0.5}, vrow{l(i1.ID, "out_err"), 0},
+			vrow{l(i1.ID, "in_32"), 999}, // a stale 32-bit series must not win over the 64-bit counter
+			vrow{l(i2.ID, "in_32"), 100}, vrow{l(i2.ID, "out_32"), 200},
+			vrow{l(i3.ID, "in_32"), 5}, vrow{l(i3.ID, "out_32"), 5}, vrow{l(i3.ID, "in_err"), 1},
+			vrow{map[string]string{"k": "uptime"}, 86400},
+		), nil
+	}
+	var d api.DeviceView
+	rec := e.getJSON(t, "/api/v1/devices/"+core.Slug, &d)
+	assertNoLeaks(t, "device detail", rec.Body.Bytes())
+	var rateQueries []string
+	for _, c := range e.q.queries() {
+		if strings.Contains(c.expr, "ifHCInOctets") {
+			rateQueries = append(rateQueries, c.expr)
+		}
+	}
+	if len(rateQueries) != 1 || !strings.Contains(rateQueries[0], "rate(ifHCInOctets{device=") || !strings.Contains(rateQueries[0], "[5m])*8") {
+		t.Errorf("want one batched rate query, got %q", rateQueries)
+	}
+	if d.Slug != core.Slug || d.HWSerial != "SN1" || d.SysDescr != "JunOS" || d.UptimeSeconds == nil || *d.UptimeSeconds != 86400 ||
+		len(d.Parents) != 1 || d.Parents[0].Slug != other.Slug || d.Parents[0].Name != "Other" || d.Groups == nil ||
+		d.Reachability == "" || d.PollState != "ok" || len(d.Interfaces) != 5 {
+		t.Fatalf("detail: %+v", d)
+	}
+	by := map[string]api.InterfaceView{}
+	for _, i := range d.Interfaces {
+		by[i.ID] = i
+	}
+	if x := by[i1.ID]; x.InBPS == nil || *x.InBPS != 8e6 || *x.OutBPS != 4e6 || *x.InErrorsPS != 0.5 || x.OutErrorsPS == nil {
+		t.Errorf("hc interface: %+v", x)
+	}
+	if x := by[i2.ID]; x.InBPS == nil || *x.InBPS != 100 || *x.OutBPS != 200 || x.InErrorsPS != nil {
+		t.Errorf("32-bit interface: %+v", x)
+	}
+	if x := by[i3.ID]; !x.Unreliable || x.InBPS != nil || x.OutBPS != nil || x.InErrorsPS != nil {
+		t.Errorf("unreliable interface must have null rates: %+v", x)
+	}
+	if x := by[i4.ID]; x.InBPS != nil || x.OutBPS != nil {
+		t.Errorf("unknown rate must be null: %+v", x)
+	}
+	if x := by[i5.ID]; x.RetiredAt == nil {
+		t.Errorf("retired interface should carry retired_at: %+v", x)
+	}
+	// every nullable field is present as null, not omitted
+	var raw map[string]any
+	_ = json.Unmarshal(rec.Body.Bytes(), &raw)
+	ifs := raw["interfaces"].([]any)[3].(map[string]any)
+	for _, k := range []string{"in_bps", "out_bps", "in_errors_ps", "out_errors_ps", "retired_at"} {
+		if v, ok := ifs[k]; !ok || v != nil {
+			t.Errorf("%s should be present and null: %v %v", k, v, ok)
+		}
+	}
+}
+
+func TestDeviceDetailWithStoreDownStillServes(t *testing.T) {
+	e := newEnv(t, 0)
+	d := e.device(t, "Core", "", "")
+	e.iface(t, d, 1, "e1", "")
+	e.q.err = context.DeadlineExceeded
+	var v api.DeviceView
+	e.getJSON(t, "/api/v1/devices/"+d.Slug, &v)
+	if len(v.Interfaces) != 1 || v.Interfaces[0].InBPS != nil || v.UptimeSeconds != nil {
+		t.Errorf("rates should be null when the store fails: %+v", v)
+	}
+	isProblem(t, e.do("GET", "/api/v1/devices/nope", ""), 404)
+}
+
+func TestPutDeviceEditsAndAudits(t *testing.T) {
+	e := newEnv(t, 0)
+	a := e.device(t, "A", "yyz", "core")
+	b := e.device(t, "B", "yyz", "edge")
+	var v api.DeviceView
+	rec := e.do("PUT", "/api/v1/devices/"+b.Slug,
+		`{"name":"B2","site":"yul","role":"dist","enabled":false,"parents":["`+a.Slug+`"]}`)
+	if rec.Code != 200 {
+		t.Fatalf("PUT: %d %s", rec.Code, rec.Body)
+	}
+	_ = json.Unmarshal(rec.Body.Bytes(), &v)
+	if v.Name != "B2" || v.Site != "yul" || v.Role != "dist" || v.Enabled || len(v.Parents) != 1 || v.Parents[0].Slug != a.Slug {
+		t.Errorf("edited: %+v", v)
+	}
+	if v.Slug != b.Slug {
+		t.Error("slug is immutable")
+	}
+	if e.ref.n.Load() != 1 {
+		t.Error("poller not refreshed")
+	}
+	// a partial body leaves the rest alone; an empty parents list clears them
+	rec = e.do("PUT", "/api/v1/devices/"+b.Slug, `{"parents":[]}`)
+	_ = json.Unmarshal(rec.Body.Bytes(), &v)
+	if rec.Code != 200 || v.Name != "B2" || v.Site != "yul" || len(v.Parents) != 0 {
+		t.Errorf("partial edit: %d %+v", rec.Code, v)
+	}
+	audit, _, _ := e.st.ListAudit(t.Context(), store.Page{})
+	var edits int
+	for _, a := range audit {
+		if a.Action == "device.edit" && a.Object == b.Slug {
+			edits++
+		}
+	}
+	if edits != 2 {
+		t.Errorf("audit has %d device.edit rows, want 2: %+v", edits, audit)
+	}
+	for body, status := range map[string]int{
+		`{"name":""}`: 422, `{"name":"   "}`: 422, `{"parents":["nope"]}`: 422, `{"enabled":"yes"}`: 422, `{"bogus":1}`: 422,
+		`{"snmp":{"version":"v2c"}}`: 422,
+	} {
+		isProblem(t, e.do("PUT", "/api/v1/devices/"+b.Slug, body), status)
+	}
+	isProblem(t, e.do("PUT", "/api/v1/devices/nope", `{}`), 404)
+	if err := e.st.RetireDevice(t.Context(), a.ID); err != nil {
+		t.Fatal(err)
+	}
+	isProblem(t, e.do("PUT", "/api/v1/devices/"+a.Slug, `{"name":"x"}`), 409)
+	isProblem(t, e.do("PUT", "/api/v1/devices/"+b.Slug, `{"parents":["`+a.Slug+`"]}`), 422) // retired parent
+}
+
+func TestPutDeviceRejectsParentCyclesNamingThePath(t *testing.T) {
+	e := newEnv(t, 0)
+	a := e.device(t, "A", "", "")
+	b := e.device(t, "B", "", "")
+	c := e.device(t, "C", "", "")
+	set := func(d *store.Device, parents ...*store.Device) {
+		ids := make([]int64, len(parents))
+		for i, p := range parents {
+			ids[i] = p.ID
+		}
+		if err := e.st.SetParents(t.Context(), d.ID, store.RelNetwork, ids); err != nil {
+			t.Fatal(err)
+		}
+	}
+	set(c, b) // C depends on B
+	set(b, a) // B depends on A
+	rec := e.do("PUT", "/api/v1/devices/"+a.Slug, `{"parents":["`+c.Slug+`"]}`)
+	isProblem(t, rec, 422)
+	want := a.Slug + " -> " + c.Slug + " -> " + b.Slug + " -> " + a.Slug
+	if !strings.Contains(rec.Body.String(), want) {
+		t.Errorf("cycle path missing; want %q in %s", want, rec.Body)
+	}
+	rec = e.do("PUT", "/api/v1/devices/"+a.Slug, `{"parents":["`+a.Slug+`"]}`)
+	isProblem(t, rec, 422)
+	if !strings.Contains(rec.Body.String(), a.Slug+" -> "+a.Slug) {
+		t.Errorf("self parent: %s", rec.Body)
+	}
+	if got, _ := e.st.ListParents(t.Context(), a.ID, ""); len(got) != 0 {
+		t.Errorf("a rejected edit must not change parents: %+v", got)
+	}
+	// a diamond is not a cycle
+	d := e.device(t, "D", "", "")
+	if rec := e.do("PUT", "/api/v1/devices/"+d.Slug, `{"parents":["`+b.Slug+`","`+c.Slug+`"]}`); rec.Code != 200 {
+		t.Errorf("diamond: %d %s", rec.Code, rec.Body)
+	}
+}
+
+func TestPutDeviceReplacesSNMPCredentialWithoutLeakingIt(t *testing.T) {
+	e := newEnv(t, 0)
+	cred := &store.SNMPCredential{Name: "old", Version: "v2c", Community: "old-community-xyz"}
+	if err := e.st.CreateCredential(t.Context(), cred); err != nil {
+		t.Fatal(err)
+	}
+	d := e.device(t, "A", "", "", func(d *store.Device) { d.SNMPCredentialID = &cred.ID })
+	rec := e.do("PUT", "/api/v1/devices/"+d.Slug,
+		`{"snmp":{"version":"v3","v3_user":"nmon","v3_auth_proto":"SHA256","v3_auth_pass":"auth-secret-123","v3_priv_proto":"AES","v3_priv_pass":"priv-secret-456","port":1161}}`)
+	if rec.Code != 200 {
+		t.Fatalf("PUT: %d %s", rec.Code, rec.Body)
+	}
+	assertNoLeaks(t, "PUT response", rec.Body.Bytes(), "auth-secret-123", "priv-secret-456", "old-community-xyz")
+	var v api.DeviceView
+	_ = json.Unmarshal(rec.Body.Bytes(), &v)
+	if v.SNMPVersion != "v3" {
+		t.Errorf("snmp_version %q", v.SNMPVersion)
+	}
+	got, err := e.st.GetDeviceBySlug(t.Context(), d.Slug)
+	if err != nil || got.SNMPPort != 1161 || *got.SNMPCredentialID == cred.ID {
+		t.Fatalf("device after: %+v %v", got, err)
+	}
+	c, err := e.st.GetCredential(t.Context(), *got.SNMPCredentialID)
+	if err != nil || c.V3AuthPass != "auth-secret-123" || c.V3User != "nmon" {
+		t.Errorf("stored credential: %+v %v", c, err)
+	}
+	if _, err := e.st.GetCredential(t.Context(), cred.ID); err == nil {
+		t.Error("the replaced credential should be deleted")
+	}
+	audit, _, _ := e.st.ListAudit(t.Context(), store.Page{})
+	for _, a := range audit {
+		if strings.Contains(a.After+a.Before, "secret") {
+			t.Errorf("audit row leaks a secret: %+v", a)
+		}
+	}
+	vm := e.device(t, "VM", "", "", func(d *store.Device) { d.Kind = store.KindVM })
+	isProblem(t, e.do("PUT", "/api/v1/devices/"+vm.Slug, `{"snmp":{"version":"v2c","community":"c"}}`), 422)
+}

internal/api/device_put.go

@@ -0,0 +1,144 @@
+package api
+
+import (
+	"context"
+	"errors"
+	"strings"
+
+	"github.com/danielgtaylor/huma/v2"
+
+	"github.com/v10networks/nmon/internal/store"
+)
+
+// PutDeviceBody is the body of PUT /api/v1/devices/{slug}. Absent fields stay
+// as they are; an empty parents list removes every parent.
+type PutDeviceBody struct {
+	Name    *string   `json:"name,omitempty" minLength:"1" maxLength:"255"`
+	Site    *string   `json:"site,omitempty"`
+	Role    *string   `json:"role,omitempty"`
+	Enabled *bool     `json:"enabled,omitempty"`
+	Parents []string  `json:"parents,omitempty" doc:"Parent device slugs, replacing the current parents."`
+	SNMP    *SNMPBody `json:"snmp,omitempty" doc:"Replaces the SNMP credential; secrets are write-only."`
+}
+
+func isNotFound(err error) bool { return errors.Is(err, store.ErrNotFound) }
+
+func (s *server) putDevice(ctx context.Context, in *struct {
+	Slug string `path:"slug" doc:"Device slug."`
+	Body PutDeviceBody
+}) (*deviceOut, error) {
+	dev, err := s.Store.GetDeviceBySlug(ctx, in.Slug)
+	if err != nil {
+		return nil, s.storeErr(err)
+	}
+	if dev.PurgedAt != nil {
+		return nil, huma.Error404NotFound("not found")
+	}
+	if dev.RetiredAt != nil {
+		return nil, huma.Error409Conflict("device is retired; reattach it before editing")
+	}
+	plan, err := s.planEdit(ctx, dev, in.Body)
+	if err != nil {
+		return nil, err
+	}
+	if err := s.applyEdit(ctx, dev, plan); err != nil {
+		return nil, s.storeErr(err)
+	}
+	s.Poller.Refresh()
+	return s.view(ctx, dev.Slug)
+}
+
+// editPlan is a validated edit: the device as it will be, the parents to set
+// (nil leaves them) and the credential to create (nil leaves it).
+type editPlan struct {
+	after      store.Device
+	setParents bool
+	parents    []*store.Device
+	cred       *store.SNMPCredential
+	change     map[string]any // what the audit row records; never a secret
+}
+
+// planEdit validates body against the device without writing anything.
+func (s *server) planEdit(ctx context.Context, dev *store.Device, b PutDeviceBody) (*editPlan, error) {
+	p := &editPlan{after: *dev, change: map[string]any{}}
+	set := func(field string, dst *string, v *string) {
+		if v != nil && *v != *dst {
+			*dst = *v
+			p.change[field] = *v
+		}
+	}
+	set("name", &p.after.Name, b.Name)
+	set("site", &p.after.Site, b.Site)
+	set("role", &p.after.Role, b.Role)
+	if b.Name != nil && strings.TrimSpace(*b.Name) == "" {
+		return nil, huma.Error422UnprocessableEntity("name must not be empty")
+	}
+	if b.Enabled != nil && *b.Enabled != dev.Enabled {
+		p.after.Enabled = *b.Enabled
+		p.change["enabled"] = *b.Enabled
+	}
+	if b.Parents != nil {
+		parents, err := s.resolveParents(ctx, dev, b.Parents)
+		if err != nil {
+			return nil, err
+		}
+		p.setParents, p.parents = true, parents
+		p.change["parents"] = b.Parents
+	}
+	if b.SNMP != nil {
+		if dev.Kind != store.KindNetwork {
+			return nil, huma.Error422UnprocessableEntity("snmp applies to network devices only")
+		}
+		cred, err := s.credential(b.SNMP)
+		if err != nil {
+			return nil, err
+		}
+		p.cred = cred
+		p.after.SNMPPort = b.SNMP.Port
+		p.change["snmp"] = map[string]any{"version": b.SNMP.Version, "port": b.SNMP.Port, "replaced": true}
+	}
+	return p, nil
+}
+
+// applyEdit writes the plan and its audit row in one transaction. The old
+// credential is deleted once nothing uses it.
+func (s *server) applyEdit(ctx context.Context, dev *store.Device, p *editPlan) error {
+	return s.Store.WithTx(ctx, func(tx store.Store) error {
+		after := p.after
+		oldCred := dev.SNMPCredentialID
+		if p.cred != nil {
+			if err := tx.CreateCredential(ctx, p.cred); err != nil {
+				return err
+			}
+			after.SNMPCredentialID = &p.cred.ID
+		}
+		if err := tx.UpdateDevice(ctx, &after); err != nil {
+			return err
+		}
+		if p.setParents {
+			if err := setParentLinks(ctx, tx, &after, p.parents); err != nil {
+				return err
+			}
+		}
+		if p.cred != nil && oldCred != nil {
+			if err := tx.DeleteCredential(ctx, *oldCred); err != nil && !errors.Is(err, store.ErrConflict) {
+				return err
+			}
+		}
+		return tx.AppendAudit(ctx, "anonymous", "device.edit", dev.Slug, nil, p.change)
+	})
+}
+
+// setParentLinks replaces the device's parents. VMs and containers depend on
+// their host (hosted_on); everything else on the network path.
+func setParentLinks(ctx context.Context, tx store.Store, d *store.Device, parents []*store.Device) error {
+	rel := store.RelNetwork
+	if d.Kind == store.KindVM || d.Kind == store.KindContainer {
+		rel = store.RelHostedOn
+	}
+	ids := make([]int64, len(parents))
+	for i, p := range parents {
+		ids[i] = p.ID
+	}
+	return tx.SetParents(ctx, d.ID, rel, ids)
+}

internal/api/device_view.go

@@ -0,0 +1,210 @@
+package api
+
+import (
+	"context"
+	"net/http"
+	"time"
+
+	"github.com/danielgtaylor/huma/v2"
+
+	"github.com/v10networks/nmon/internal/store"
+)
+
+// DeviceRef names a device in another object. Devices are addressed by slug.
+type DeviceRef struct {
+	Slug string `json:"slug"`
+	Name string `json:"name"`
+}
+
+// GroupView is a group an interface of the device belongs to.
+type GroupView struct {
+	ID   string `json:"id"`
+	Name string `json:"name"`
+	Kind string `json:"kind" enum:"site,customer,role,custom"`
+}
+
+// InterfaceView is an interface as the API shows it, addressed by ULID. The
+// rate fields are five-minute rates from the hot store, null when unknown or
+// when the interface is unreliable (its counters cannot be trusted).
+type InterfaceView struct {
+	ID             string     `json:"id" doc:"Immutable ULID."`
+	IfIndex        int64      `json:"ifindex" doc:"Current ifIndex; may change, the ID does not."`
+	IfName         string     `json:"ifname"`
+	IfDescr        string     `json:"ifdescr"`
+	IfAlias        string     `json:"ifalias"`
+	IfPhysAddr     string     `json:"ifphysaddr"`
+	IfSpeed        int64      `json:"ifspeed" doc:"bits per second"`
+	IfHighSpeed    int64      `json:"ifhighspeed" doc:"megabits per second"`
+	IfType         int64      `json:"iftype"`
+	AdminStatus    int64      `json:"admin_status" doc:"ifAdminStatus: 1 up, 2 down, 3 testing"`
+	OperStatus     int64      `json:"oper_status" doc:"ifOperStatus: 1 up, 2 down, 3 testing, 4 unknown, 5 dormant, 6 notPresent, 7 lowerLayerDown"` //nolint:lll // struct tag text is the OpenAPI doc; cannot wrap
+	HasHCCounters  bool       `json:"has_hc_counters"`
+	Excluded       bool       `json:"excluded"`
+	FirstSeen      time.Time  `json:"first_seen"`
+	LastDiscovered time.Time  `json:"last_discovered"`
+	Unreliable     bool       `json:"unreliable" doc:"Counters cannot be trusted (32-bit counters on a fast link); no rate is reported."`
+	RetiredAt      *time.Time `json:"retired_at" nullable:"true"`
+	InBPS          *float64   `json:"in_bps" nullable:"true" doc:"Inbound bits per second over 5 minutes."`
+	OutBPS         *float64   `json:"out_bps" nullable:"true"`
+	InErrorsPS     *float64   `json:"in_errors_ps" nullable:"true" doc:"Inbound errors per second over 5 minutes."`
+	OutErrorsPS    *float64   `json:"out_errors_ps" nullable:"true"`
+}
+
+// DeviceView is a device as the API shows it. It carries no numeric ID and no credential.
+type DeviceView struct {
+	Slug          string          `json:"slug" doc:"Immutable public key."`
+	Name          string          `json:"name"`
+	Kind          string          `json:"kind"`
+	Site          string          `json:"site"`
+	Role          string          `json:"role"`
+	Profile       string          `json:"profile"`
+	Enabled       bool            `json:"enabled"`
+	MgmtIP        string          `json:"mgmt_ip"`
+	Addresses     []string        `json:"addresses"`
+	SNMPVersion   string          `json:"snmp_version,omitempty"`
+	SysName       string          `json:"sys_name"`
+	SysObjectID   string          `json:"sys_object_id"`
+	SysDescr      string          `json:"sys_descr"`
+	HWSerial      string          `json:"hw_serial"`
+	UptimeSeconds *float64        `json:"uptime_seconds" nullable:"true" doc:"sysUpTime from the hot store; null when unknown."`
+	Reachability  string          `json:"reachability" enum:"up,down,warning,unknown,maintenance"`
+	PollState     string          `json:"poll_state" enum:"ok,degraded,backoff"`
+	Warnings      []string        `json:"warnings"`
+	LastSeen      *time.Time      `json:"last_seen" nullable:"true"`
+	CreatedAt     time.Time       `json:"created_at"`
+	RetiredAt     *time.Time      `json:"retired_at,omitempty" nullable:"true"`
+	Parents       []DeviceRef     `json:"parents"`
+	Groups        []GroupView     `json:"groups"`
+	Interfaces    []InterfaceView `json:"interfaces"`
+}
+
+type deviceOut struct{ Body DeviceView }
+
+func (s *server) registerDeviceViews(api huma.API) {
+	huma.Register(api, huma.Operation{
+		OperationID: "get-device", Method: http.MethodGet, Path: "/api/v1/devices/{slug}", Tags: []string{"devices"},
+		Summary:     "Get a device, its interfaces with live rates, parents and groups",
+		Description: "Rates are one batched query to the hot store; they are null when the store is unavailable.",
+		Errors:      []int{http.StatusNotFound},
+	}, s.getDevice)
+	huma.Register(api, huma.Operation{
+		OperationID: "put-device", Method: http.MethodPut, Path: "/api/v1/devices/{slug}", Tags: []string{"devices"},
+		Summary: "Edit a device",
+		Description: "Only the fields present change. parents replaces the parent list (by slug) and is rejected with 422 " +
+			"naming the path when it would make a cycle. snmp replaces the credential.",
+		Errors: []int{http.StatusNotFound, http.StatusConflict, http.StatusUnprocessableEntity},
+	}, s.putDevice)
+}
+
+func (s *server) getDevice(ctx context.Context, in *struct {
+	Slug string `path:"slug" doc:"Device slug."`
+}) (*deviceOut, error) {
+	return s.view(ctx, in.Slug)
+}
+
+// view loads the device and everything shown with it.
+func (s *server) view(ctx context.Context, slug string) (*deviceOut, error) {
+	d, err := s.Store.GetDeviceBySlug(ctx, slug)
+	if err != nil {
+		return nil, s.storeErr(err)
+	}
+	if d.PurgedAt != nil {
+		return nil, huma.Error404NotFound("not found")
+	}
+	v := DeviceView{
+		Slug: d.Slug, Name: d.Name, Kind: d.Kind, Site: d.Site, Role: d.Role, Profile: d.Profile, Enabled: d.Enabled,
+		MgmtIP: d.MgmtIP, SysName: d.SysName, SysObjectID: d.SysObjectID, SysDescr: d.SysDescr, HWSerial: d.HWSerial,
+		PollState: pollStateOf(d), Warnings: nonNil(d.Warnings), LastSeen: utcp(d.LastSeen), CreatedAt: d.CreatedAt.UTC(),
+		RetiredAt: utcp(d.RetiredAt), Addresses: []string{}, Parents: []DeviceRef{}, Groups: []GroupView{},
+		Reachability: s.Reachability.Reachability(ctx, []store.Device{*d})[d.Slug],
+	}
+	if err := s.fillRelations(ctx, d, &v); err != nil {
+		return nil, s.storeErr(err)
+	}
+	if err := s.fillInterfaces(ctx, d, &v); err != nil {
+		return nil, s.storeErr(err)
+	}
+	return &deviceOut{Body: v}, nil
+}
+
+// fillRelations adds addresses, the credential's version (never its secrets), parents and groups.
+func (s *server) fillRelations(ctx context.Context, d *store.Device, v *DeviceView) error {
+	addrs, err := s.Store.ListAddresses(ctx, d.ID)
+	if err != nil {
+		return err
+	}
+	for _, a := range addrs {
+		v.Addresses = append(v.Addresses, a.Addr)
+	}
+	if d.SNMPCredentialID != nil {
+		c, err := s.Store.GetCredential(ctx, *d.SNMPCredentialID)
+		if err != nil {
+			return err
+		}
+		v.SNMPVersion = c.Version
+	}
+	links, err := s.Store.ListParents(ctx, d.ID, "")
+	if err != nil {
+		return err
+	}
+	seen := map[int64]bool{}
+	for _, l := range links {
+		if seen[l.ParentID] {
+			continue
+		}
+		seen[l.ParentID] = true
+		p, err := s.Store.GetDeviceByID(ctx, l.ParentID)
+		if err != nil {
+			return err
+		}
+		v.Parents = append(v.Parents, DeviceRef{Slug: p.Slug, Name: p.Name})
+	}
+	groups, err := s.Store.DeviceGroups(ctx, d.ID)
+	if err != nil {
+		return err
+	}
+	for _, g := range groups {
+		v.Groups = append(v.Groups, GroupView{ID: itoa(int(g.ID)), Name: g.Name, Kind: g.Kind})
+	}
+	return nil
+}
+
+// fillInterfaces adds the device's interfaces, retired ones included, with live rates.
+func (s *server) fillInterfaces(ctx context.Context, d *store.Device, v *DeviceView) error {
+	ifs, err := s.Store.ListInterfaces(ctx, d.ID, true)
+	if err != nil {
+		return err
+	}
+	var rates map[string]*ifRates
+	v.Interfaces = make([]InterfaceView, 0, len(ifs))
+	if len(ifs) > 0 || d.Kind == store.KindNetwork {
+		rates, v.UptimeSeconds = s.liveRates(ctx, `device=`+quote(d.Slug), true)
+	}
+	for i := range ifs {
+		v.Interfaces = append(v.Interfaces, interfaceView(&ifs[i], rates[ifs[i].ID]))
+	}
+	return nil
+}
+
+func interfaceView(i *store.Interface, r *ifRates) InterfaceView {
+	in, out := r.bps(i)
+	inE, outE := r.errs(i)
+	return InterfaceView{
+		ID: i.ID, IfIndex: i.IfIndex, IfName: i.IfName, IfDescr: i.IfDescr, IfAlias: i.IfAlias,
+		IfPhysAddr: i.IfPhysAddr, IfSpeed: i.IfSpeed, IfHighSpeed: i.IfHighSpeed, IfType: i.IfType,
+		AdminStatus: i.AdminStatus, OperStatus: i.OperStatus, HasHCCounters: i.HasHCCounters, Excluded: i.Excluded,
+		FirstSeen: i.FirstSeen.UTC(), LastDiscovered: i.LastDiscovered.UTC(), Unreliable: i.Unreliable,
+		RetiredAt: utcp(i.RetiredAt), InBPS: in, OutBPS: out, InErrorsPS: inE, OutErrorsPS: outE,
+	}
+}
+
+// unreliableReason says why an interface's counters cannot be trusted.
+func unreliableReason(i *store.Interface) string {
+	switch {
+	case !i.HasHCCounters:
+		return "counter_32bit_fast_link"
+	case i.CounterDiscontinuity > 0:
+		return "counter_discontinuity"
+	}
+	return "counter_unreliable"
+}

internal/api/devices.go

@@ -3,13 +3,16 @@ package api
 import (
 	"context"
 	"fmt"
+	"net/http"
 	"net/netip"
+	"slices"
 	"time"
 
 	"github.com/danielgtaylor/huma/v2"
 
 	"github.com/v10networks/nmon/internal/discovery"
 	"github.com/v10networks/nmon/internal/snmp"
+	"github.com/v10networks/nmon/internal/snmptarget"
 	"github.com/v10networks/nmon/internal/store"
 	"github.com/v10networks/nmon/internal/ulid"
 )
@@ -25,146 +28,72 @@ type SNMPBody struct {
 	V3PrivProto string `json:"v3_priv_proto,omitempty" doc:"DES, AES (default), AES192 or AES256."`
 	V3PrivPass  string `json:"v3_priv_pass,omitempty"`
 	V3Context   string `json:"v3_context,omitempty"`
+	Port        int    `json:"port,omitempty" minimum:"1" maximum:"65535" doc:"UDP port; default 161."`
 }
 
 // AddDeviceBody is the body of POST /api/v1/devices.
 type AddDeviceBody struct {
 	Name      string    `json:"name" minLength:"1" maxLength:"255" example:"core-sw1"`
-	Addresses []string  `json:"addresses" minItems:"1" doc:"Management addresses; an IPv6 address is preferred over IPv4." example:"[\"2001:db8::1\"]"`
+	Addresses []string  `json:"addresses" minItems:"1" doc:"Management addresses; an IPv6 address is preferred over IPv4." example:"[\"2001:db8::1\"]"` //nolint:lll // struct tag, cannot wrap
 	Kind      string    `json:"kind,omitempty" enum:"network,vm,container,check_only" default:"network"`
 	Site      string    `json:"site,omitempty"`
 	Role      string    `json:"role,omitempty"`
 	SNMP      *SNMPBody `json:"snmp,omitempty" doc:"Required for kind network."`
+	// Reattach and CreateNew answer a 409 reattach_candidates response.
+	Reattach  string `json:"reattach,omitempty" doc:"Slug of a retired device to restore instead of creating a new one (its slug and interface IDs come back)."` //nolint:lll // struct tag text is the OpenAPI doc; cannot wrap
+	CreateNew bool   `json:"create_new,omitempty" doc:"Create a new device although a retired one matches the address or sysName."`
 }
 
-// InterfaceView is an interface as the API shows it, addressed by ULID.
-type InterfaceView struct {
-	ID             string    `json:"id" doc:"Immutable ULID."`
-	IfIndex        int64     `json:"ifindex" doc:"Current ifIndex; may change, the ID does not."`
-	IfName         string    `json:"ifname"`
-	IfDescr        string    `json:"ifdescr"`
-	IfAlias        string    `json:"ifalias"`
-	IfPhysAddr     string    `json:"ifphysaddr"`
-	IfSpeed        int64     `json:"ifspeed" doc:"bits per second"`
-	IfHighSpeed    int64     `json:"ifhighspeed" doc:"megabits per second"`
-	IfType         int64     `json:"iftype"`
-	AdminStatus    int64     `json:"admin_status"`
-	OperStatus     int64     `json:"oper_status"`
-	HasHCCounters  bool      `json:"has_hc_counters"`
-	Excluded       bool      `json:"excluded"`
-	FirstSeen      time.Time `json:"first_seen"`
-	LastDiscovered time.Time `json:"last_discovered"`
+// reattachCandidate is a retired device offered in a 409.
+type reattachCandidate struct {
+	Slug      string    `json:"slug"`
+	Name      string    `json:"name"`
+	RetiredAt time.Time `json:"retired_at"`
 }
 
-// DeviceView is a device as the API shows it. It carries no numeric ID and no credential.
-type DeviceView struct {
-	Slug        string          `json:"slug" doc:"Immutable public key."`
-	Name        string          `json:"name"`
-	Kind        string          `json:"kind"`
-	Site        string          `json:"site"`
-	Role        string          `json:"role"`
-	Profile     string          `json:"profile"`
-	Enabled     bool            `json:"enabled"`
-	MgmtIP      string          `json:"mgmt_ip"`
-	Addresses   []string        `json:"addresses"`
-	SNMPVersion string          `json:"snmp_version,omitempty"`
-	SysName     string          `json:"sys_name"`
-	SysObjectID string          `json:"sys_object_id"`
-	SysDescr    string          `json:"sys_descr"`
-	PollState   string          `json:"poll_state"`
-	Warnings    []string        `json:"warnings"`
-	LastSeen    *time.Time      `json:"last_seen,omitempty"`
-	CreatedAt   time.Time       `json:"created_at"`
-	RetiredAt   *time.Time      `json:"retired_at,omitempty"`
-	Interfaces  []InterfaceView `json:"interfaces"`
+// reattachProblem is the 409 problem with the retired devices the client may restore.
+type reattachProblem struct {
+	Problem
+	Candidates []reattachCandidate `json:"reattach_candidates"`
 }
 
-type deviceOut struct{ Body DeviceView }
-
 func (s *server) registerDevices(api huma.API) {
 	huma.Register(api, huma.Operation{
 		OperationID: "add-device", Method: "POST", Path: "/api/v1/devices", Tags: []string{"devices"},
-		Summary:       "Add a device",
-		Description:   "Creates the credential, device and addresses, runs seed discovery synchronously (30 s limit) and starts polling. A device that does not answer SNMP is rejected with 502 and nothing is stored.",
-		DefaultStatus: 201,
-		Errors:        []int{409, 422, 502},
+		Summary: "Add a device",
+		Description: "Creates the credential, device and addresses, runs seed discovery synchronously (30 s limit) and " +
+			"starts polling. A device that does not answer SNMP is rejected with 502 and nothing is stored.",
+		DefaultStatus: http.StatusCreated,
+		Errors:        []int{http.StatusConflict, http.StatusUnprocessableEntity, http.StatusBadGateway},
 	}, s.addDevice)
-	huma.Register(api, huma.Operation{
-		OperationID: "get-device", Method: "GET", Path: "/api/v1/devices/{slug}", Tags: []string{"devices"},
-		Summary: "Get a device and its interfaces",
-		Errors:  []int{404},
-	}, s.getDevice)
 }
 
-func (s *server) addDevice(ctx context.Context, in *struct{ Body AddDeviceBody }) (*deviceOut, error) {
-	b := in.Body
-	kind := b.Kind
-	if kind == "" {
-		kind = store.KindNetwork
-	}
-	var addrs []netip.Addr
-	for _, a := range b.Addresses {
-		ip, err := netip.ParseAddr(a)
-		if err != nil {
-			return nil, huma.Error422UnprocessableEntity(fmt.Sprintf("address %q is not an IP address", a))
-		}
-		addrs = append(addrs, ip.WithZone("").Unmap())
-	}
-	if len(addrs) == 0 {
-		return nil, huma.Error422UnprocessableEntity("at least one address is required")
-	}
-	if kind == store.KindNetwork && b.SNMP == nil {
-		return nil, huma.Error422UnprocessableEntity("snmp credentials are required for kind network")
-	}
-	var (
-		cred *store.SNMPCredential
-		res  *discovery.Result
-	)
-	if b.SNMP != nil {
-		var err error
-		if cred, err = s.credential(b.SNMP); err != nil {
-			return nil, err
-		}
-		pref := addrs[0]
-		for _, a := range addrs {
-			if a.Is6() {
-				pref = a
-				break
-			}
-		}
-		if res, err = s.collect(ctx, pref, cred); err != nil {
-			return nil, err
-		}
-	}
+// addRequest is an AddDeviceBody after validation: defaults applied and
+// addresses parsed.
+type addRequest struct {
+	AddDeviceBody
+	kind  string
+	addrs []netip.Addr
+	strs  []string // addrs in canonical text form, as stored
+}
 
-	var slug string
-	err := s.Store.WithTx(ctx, func(tx store.Store) error {
-		d := &store.Device{Name: b.Name, Kind: kind, Site: b.Site, Role: b.Role, Enabled: true, Profile: "generic"}
-		if cred != nil {
-			if err := tx.CreateCredential(ctx, cred); err != nil {
-				return err
-			}
-			d.SNMPCredentialID = &cred.ID
-		}
-		if err := tx.CreateDevice(ctx, d); err != nil {
-			return err
-		}
-		strs := make([]string, len(addrs))
-		for i, a := range addrs {
-			strs[i] = a.String()
-		}
-		if err := tx.SetAddresses(ctx, d.ID, strs); err != nil {
-			return err
-		}
-		if res != nil {
-			if err := discovery.Apply(ctx, tx, d, res, s.Clock); err != nil {
-				return err
-			}
-		}
-		slug = d.Slug
-		return tx.AppendAudit(ctx, "anonymous", "device.add", d.Slug, nil,
-			map[string]any{"name": d.Name, "kind": d.Kind, "addresses": strs})
-	})
+// addDevice validates the request, collects from the device before anything is
+// stored, decides between a new device and a reattach, then persists in one
+// transaction.
+func (s *server) addDevice(ctx context.Context, in *struct{ Body AddDeviceBody }) (*deviceOut, error) {
+	req, err := validateAdd(in.Body)
+	if err != nil {
+		return nil, err
+	}
+	cred, res, err := s.credentialAndSeed(ctx, req)
+	if err != nil {
+		return nil, err
+	}
+	restore, err := s.reattachDecision(ctx, req, res)
+	if err != nil {
+		return nil, err
+	}
+	slug, err := s.persistDevice(ctx, req, cred, res, restore)
 	if err != nil {
 		return nil, s.storeErr(err)
 	}
@@ -172,6 +101,183 @@ func (s *server) addDevice(ctx context.Context, in *struct{ Body AddDeviceBody }
 	return s.view(ctx, slug)
 }
 
+// validateAdd applies the kind default and parses the addresses.
+func validateAdd(b AddDeviceBody) (*addRequest, error) {
+	req := &addRequest{AddDeviceBody: b, kind: b.Kind}
+	if req.kind == "" {
+		req.kind = store.KindNetwork
+	}
+	for _, a := range b.Addresses {
+		ip, err := netip.ParseAddr(a)
+		if err != nil {
+			return nil, huma.Error422UnprocessableEntity(fmt.Sprintf("address %q is not an IP address", a))
+		}
+		ip = ip.WithZone("").Unmap()
+		req.addrs = append(req.addrs, ip)
+		req.strs = append(req.strs, ip.String())
+	}
+	if len(req.addrs) == 0 {
+		return nil, huma.Error422UnprocessableEntity("at least one address is required")
+	}
+	if req.kind == store.KindNetwork && b.SNMP == nil {
+		return nil, huma.Error422UnprocessableEntity("snmp credentials are required for kind network")
+	}
+	return req, nil
+}
+
+// credentialAndSeed builds the credential from the request and runs the seed
+// walk against the preferred address. Both are nil when the request has no
+// SNMP block.
+func (s *server) credentialAndSeed(ctx context.Context, req *addRequest) (*store.SNMPCredential, *discovery.Result, error) {
+	if req.SNMP == nil {
+		return nil, nil, nil
+	}
+	cred, err := s.credential(req.SNMP)
+	if err != nil {
+		return nil, nil, err
+	}
+	res, err := s.collect(ctx, req.preferredAddr(), s.port(req.SNMP.Port), cred)
+	if err != nil {
+		return nil, nil, err
+	}
+	return cred, res, nil
+}
+
+// preferredAddr is the first IPv6 address, else the first address.
+func (r *addRequest) preferredAddr() netip.Addr {
+	for _, a := range r.addrs {
+		if a.Is6() {
+			return a
+		}
+	}
+	return r.addrs[0]
+}
+
+// reattachDecision looks for retired devices matching the request. It returns
+// the one to restore, nil for a brand-new device, or a 409 offering the
+// candidates when the client has not chosen.
+func (s *server) reattachDecision(ctx context.Context, req *addRequest, res *discovery.Result) (*discovery.ReattachCandidate, error) {
+	if req.CreateNew {
+		return nil, nil
+	}
+	sysName := ""
+	if res != nil {
+		sysName = res.SysName
+	}
+	cands, err := discovery.FindReattachCandidates(ctx, s.Store, req.strs, sysName)
+	if err != nil {
+		return nil, s.storeErr(err)
+	}
+	if req.Reattach != "" {
+		i := slices.IndexFunc(cands, func(c discovery.ReattachCandidate) bool { return c.Slug == req.Reattach })
+		if i < 0 {
+			return nil, huma.Error422UnprocessableEntity(
+				"reattach: " + req.Reattach + " is not a retired device matching this address or sysName")
+		}
+		return &cands[i], nil
+	}
+	if len(cands) == 0 {
+		return nil, nil
+	}
+	if err := discovery.OfferReattach(ctx, s.Store, cands, req.Name, req.strs, sysName); err != nil {
+		return nil, s.storeErr(err)
+	}
+	return nil, reattachOffer(cands)
+}
+
+// reattachOffer is the 409 listing the retired devices the client may restore.
+func reattachOffer(cands []discovery.ReattachCandidate) *reattachProblem {
+	p := &reattachProblem{Candidates: make([]reattachCandidate, len(cands))}
+	p.Status, p.Title = http.StatusConflict, http.StatusText(http.StatusConflict)
+	p.Detail = "a retired device has this address or sysName; send reattach: <slug> to restore it or create_new: true to add a new device"
+	for i, c := range cands {
+		p.Candidates[i] = reattachCandidate{Slug: c.Slug, Name: c.Name, RetiredAt: c.RetiredAt}
+	}
+	return p
+}
+
+// persistDevice writes the credential, device, addresses, seeded inventory and
+// audit row in one transaction and returns the device slug.
+func (s *server) persistDevice(
+	ctx context.Context, req *addRequest, cred *store.SNMPCredential, res *discovery.Result, restore *discovery.ReattachCandidate,
+) (string, error) {
+	var slug string
+	err := s.Store.WithTx(ctx, func(tx store.Store) error {
+		d, err := s.writeDevice(ctx, tx, req, cred, res, restore)
+		if err != nil {
+			return err
+		}
+		slug = d.Slug
+		action := "device.add"
+		if restore != nil {
+			action = "device.reattach"
+		}
+		return tx.AppendAudit(ctx, "anonymous", action, d.Slug, nil,
+			map[string]any{"name": d.Name, "kind": d.Kind, "addresses": req.strs})
+	})
+	return slug, err
+}
+
+// writeDevice stores the credential, the device row, its addresses and the
+// seeded inventory inside tx.
+func (s *server) writeDevice(
+	ctx context.Context, tx store.Store, req *addRequest, cred *store.SNMPCredential, res *discovery.Result,
+	restore *discovery.ReattachCandidate,
+) (*store.Device, error) {
+	d, err := s.deviceRow(ctx, tx, req, restore)
+	if err != nil {
+		return nil, err
+	}
+	if cred != nil {
+		if err := tx.CreateCredential(ctx, cred); err != nil {
+			return nil, err
+		}
+		d.SNMPCredentialID = &cred.ID
+	}
+	if restore != nil {
+		err = tx.UpdateDevice(ctx, d)
+	} else {
+		err = tx.CreateDevice(ctx, d)
+	}
+	if err != nil {
+		return nil, err
+	}
+	if err := tx.SetAddresses(ctx, d.ID, req.strs); err != nil {
+		return nil, err
+	}
+	if res != nil {
+		if _, err := discovery.Apply(ctx, tx, d, res, s.Clock); err != nil {
+			return nil, err
+		}
+	}
+	return d, nil
+}
+
+// deviceRow is the device to write: a fresh row, or the restored one with the
+// request's name, kind and (when given) site and role laid over it.
+func (s *server) deviceRow(
+	ctx context.Context, tx store.Store, req *addRequest, restore *discovery.ReattachCandidate,
+) (*store.Device, error) {
+	d := &store.Device{Name: req.Name, Kind: req.kind, Site: req.Site, Role: req.Role, Enabled: true, Profile: "generic"}
+	if restore != nil {
+		var err error
+		if d, err = tx.Reattach(ctx, restore.DeviceID); err != nil {
+			return nil, err
+		}
+		d.Name, d.Kind, d.Enabled = req.Name, req.kind, true
+		if req.Site != "" {
+			d.Site = req.Site
+		}
+		if req.Role != "" {
+			d.Role = req.Role
+		}
+	}
+	if req.SNMP != nil {
+		d.SNMPPort = req.SNMP.Port
+	}
+	return d, nil
+}
+
 // credential validates the request's SNMP block and returns a fresh credential.
 func (s *server) credential(b *SNMPBody) (*store.SNMPCredential, error) {
 	c := &store.SNMPCredential{
@@ -201,70 +307,21 @@ func (s *server) credential(b *SNMPBody) (*store.SNMPCredential, error) {
 }
 
 // collect runs the seed walk against addr before anything is stored.
-func (s *server) collect(ctx context.Context, addr netip.Addr, cred *store.SNMPCredential) (*discovery.Result, error) {
+func (s *server) collect(ctx context.Context, addr netip.Addr, port int, cred *store.SNMPCredential) (*discovery.Result, error) {
 	dctx, cancel := context.WithTimeout(ctx, s.DiscoveryTimeout)
 	defer cancel()
-	sess, err := snmp.Dial(dctx, discovery.Target(addr, s.SNMPPort, cred, s.Clock), "discovery")
+	sess, err := snmp.Dial(dctx, snmptarget.For(addr, port, cred, s.Clock), "discovery")
 	if err != nil {
 		return nil, huma.Error422UnprocessableEntity("snmp: " + err.Error())
 	}
-	defer sess.Close()
-	res, err := discovery.Collect(dctx, sess, s.Clock)
+	defer func() { _ = sess.Close() }() // read-only session; nothing to lose on close
+	res, err := discovery.Collect(dctx, sess, s.Clock, discovery.Options{Profiles: s.Profiles})
 	if err != nil {
 		return nil, huma.Error502BadGateway("discovery of " + addr.String() + " failed: " + err.Error())
 	}
 	return res, nil
 }
 
-func (s *server) getDevice(ctx context.Context, in *struct {
-	Slug string `path:"slug" doc:"Device slug."`
-}) (*deviceOut, error) {
-	return s.view(ctx, in.Slug)
-}
-
-func (s *server) view(ctx context.Context, slug string) (*deviceOut, error) {
-	d, err := s.Store.GetDeviceBySlug(ctx, slug)
-	if err != nil {
-		return nil, s.storeErr(err)
-	}
-	if d.PurgedAt != nil {
-		return nil, huma.Error404NotFound("not found")
-	}
-	v := DeviceView{
-		Slug: d.Slug, Name: d.Name, Kind: d.Kind, Site: d.Site, Role: d.Role, Profile: d.Profile, Enabled: d.Enabled,
-		MgmtIP: d.MgmtIP, SysName: d.SysName, SysObjectID: d.SysObjectID, SysDescr: d.SysDescr,
-		PollState: d.PollState, Warnings: nonNil(d.Warnings), LastSeen: utcp(d.LastSeen), CreatedAt: d.CreatedAt.UTC(),
-		RetiredAt: utcp(d.RetiredAt), Addresses: []string{}, Interfaces: []InterfaceView{},
-	}
-	addrs, err := s.Store.ListAddresses(ctx, d.ID)
-	if err != nil {
-		return nil, s.storeErr(err)
-	}
-	for _, a := range addrs {
-		v.Addresses = append(v.Addresses, a.Addr)
-	}
-	if d.SNMPCredentialID != nil {
-		c, err := s.Store.GetCredential(ctx, *d.SNMPCredentialID)
-		if err != nil {
-			return nil, s.storeErr(err)
-		}
-		v.SNMPVersion = c.Version // the secrets stay behind
-	}
-	ifs, err := s.Store.ListInterfaces(ctx, d.ID, false)
-	if err != nil {
-		return nil, s.storeErr(err)
-	}
-	for _, i := range ifs {
-		v.Interfaces = append(v.Interfaces, InterfaceView{
-			ID: i.ID, IfIndex: i.IfIndex, IfName: i.IfName, IfDescr: i.IfDescr, IfAlias: i.IfAlias,
-			IfPhysAddr: i.IfPhysAddr, IfSpeed: i.IfSpeed, IfHighSpeed: i.IfHighSpeed, IfType: i.IfType,
-			AdminStatus: i.AdminStatus, OperStatus: i.OperStatus, HasHCCounters: i.HasHCCounters, Excluded: i.Excluded,
-			FirstSeen: i.FirstSeen.UTC(), LastDiscovered: i.LastDiscovered.UTC(),
-		})
-	}
-	return &deviceOut{Body: v}, nil
-}
-
 func nonNil(s []string) []string {
 	if s == nil {
 		return []string{}
@@ -279,3 +336,11 @@ func utcp(t *time.Time) *time.Time {
 	u := t.UTC()
 	return &u
 }
+
+// port is the device's SNMP port unless the dev-only --snmp-port override is set.
+func (s *server) port(p int) int {
+	if s.SNMPPort != 0 {
+		return s.SNMPPort
+	}
+	return p
+}

internal/api/devices_list.go

@@ -0,0 +1,136 @@
+package api
+
+import (
+	"context"
+	"net/http"
+	"time"
+
+	"github.com/danielgtaylor/huma/v2"
+
+	"github.com/v10networks/nmon/internal/store"
+)
+
+// DeviceSummary is one row of the device list.
+type DeviceSummary struct {
+	Slug            string     `json:"slug"`
+	Name            string     `json:"name"`
+	Kind            string     `json:"kind" enum:"network,vm,container,check_only"`
+	Site            string     `json:"site"`
+	Role            string     `json:"role"`
+	MgmtIP          string     `json:"mgmt_ip"`
+	Profile         string     `json:"profile"`
+	Reachability    string     `json:"reachability" enum:"up,down,warning,unknown,maintenance"`
+	PollState       string     `json:"poll_state" enum:"ok,degraded,backoff"`
+	LastSeen        *time.Time `json:"last_seen" nullable:"true"`
+	InterfacesTotal int64      `json:"interfaces_total" doc:"Active interfaces, excluded ones left out."`
+	InterfacesDown  int64      `json:"interfaces_down" doc:"Active interfaces that are admin up and not oper up."`
+	Warnings        []string   `json:"warnings"`
+}
+
+// DeviceList is a page of DeviceSummary.
+type DeviceList struct {
+	Items   []DeviceSummary `json:"items"`
+	Page    int64           `json:"page"`
+	PerPage int64           `json:"per_page"`
+	Total   int64           `json:"total"`
+}
+
+// DeviceFacets are the distinct values the list's filter dropdowns offer.
+type DeviceFacets struct {
+	Sites []string `json:"sites"`
+	Roles []string `json:"roles"`
+	Kinds []string `json:"kinds"`
+}
+
+func (s *server) registerDeviceList(api huma.API) {
+	huma.Register(api, huma.Operation{
+		OperationID: "list-devices", Method: http.MethodGet, Path: "/api/v1/devices", Tags: []string{"devices"},
+		Summary: "List devices",
+		Description: "Paged, with reachability and interface tallies. state filters on the derived reachability, " +
+			"so it is applied after the other filters.",
+	}, s.listDevices)
+	huma.Register(api, huma.Operation{
+		OperationID: "get-device-facets", Method: http.MethodGet, Path: "/api/v1/devices/facets", Tags: []string{"devices"},
+		Summary: "Distinct site, role and kind values of unretired devices",
+	}, s.deviceFacets)
+}
+
+func (s *server) listDevices(ctx context.Context, in *struct {
+	Site  string `query:"site"`
+	Role  string `query:"role"`
+	Kind  string `query:"kind" enum:"network,vm,container,check_only"`
+	Q     string `query:"q" doc:"Substring of name, slug, management address or sysName."`
+	State string `query:"state" enum:"up,down,warning,unknown,maintenance" doc:"Reachability."`
+	PageParams
+}) (*struct{ Body DeviceList }, error) {
+	f := store.DeviceFilter{Site: in.Site, Role: in.Role, Kind: in.Kind, Q: in.Q}
+	var (
+		devs  []store.Device
+		total int64
+		reach map[string]string
+		err   error
+	)
+	if in.State == "" {
+		devs, total, err = s.Store.ListDevices(ctx, f, store.Page{Offset: in.offset(), Limit: in.limit()})
+		if err == nil {
+			reach = s.Reachability.Reachability(ctx, devs)
+		}
+	} else {
+		devs, total, reach, err = s.devicesInState(ctx, f, in.State, in.PageParams)
+	}
+	if err != nil {
+		return nil, s.storeErr(err)
+	}
+	counts, err := s.Store.InterfaceCounts(ctx)
+	if err != nil {
+		return nil, s.storeErr(err)
+	}
+	out := DeviceList{Items: make([]DeviceSummary, 0, len(devs)), Page: in.pageNo(), PerPage: in.limit(), Total: total}
+	for i := range devs {
+		d := &devs[i]
+		c := counts[d.ID]
+		out.Items = append(out.Items, DeviceSummary{
+			Slug: d.Slug, Name: d.Name, Kind: d.Kind, Site: d.Site, Role: d.Role, MgmtIP: d.MgmtIP, Profile: d.Profile,
+			Reachability: reach[d.Slug], PollState: pollStateOf(d), LastSeen: utcp(d.LastSeen),
+			InterfacesTotal: c.Total, InterfacesDown: c.Down, Warnings: nonNil(d.Warnings),
+		})
+	}
+	return &struct{ Body DeviceList }{out}, nil
+}
+
+// devicesInState pages over the devices whose derived reachability is state.
+// Reachability is not a column, so every device matching the other filters is
+// classified first and the page is cut from the survivors.
+func (s *server) devicesInState(
+	ctx context.Context, f store.DeviceFilter, state string, p PageParams,
+) (page []store.Device, total int64, reach map[string]string, err error) {
+	var all []store.Device
+	for off := int64(0); ; off += store.MaxLimit {
+		rows, n, err := s.Store.ListDevices(ctx, f, store.Page{Offset: off, Limit: store.MaxLimit})
+		if err != nil {
+			return nil, 0, nil, err
+		}
+		all = append(all, rows...)
+		if off+store.MaxLimit >= n {
+			break
+		}
+	}
+	reach = s.Reachability.Reachability(ctx, all)
+	var match []store.Device
+	for _, d := range all {
+		if reach[d.Slug] == state {
+			match = append(match, d)
+		}
+	}
+	lo := min(p.offset(), int64(len(match)))
+	hi := min(lo+p.limit(), int64(len(match)))
+	return match[lo:hi], int64(len(match)), reach, nil
+}
+
+func (s *server) deviceFacets(ctx context.Context, _ *struct{}) (*struct{ Body DeviceFacets }, error) {
+	sites, roles, kinds, err := s.Store.DeviceFacets(ctx)
+	if err != nil {
+		return nil, s.storeErr(err)
+	}
+	return &struct{ Body DeviceFacets }{DeviceFacets{Sites: nonNil(sites), Roles: nonNil(roles), Kinds: nonNil(kinds)}}, nil
+}

internal/api/docs.go

@@ -0,0 +1,31 @@
+package api
+
+import (
+	"embed"
+	"io/fs"
+	"net/http"
+)
+
+// docsFS holds the Swagger UI page and its vendored swagger-ui-dist 5.17.14
+// assets, so /docs works on a network with no internet access (huma's own
+// renderers load their JavaScript from a CDN).
+//
+//go:embed docsui
+var docsFS embed.FS
+
+// registerDocs serves Swagger UI at /docs and its assets under /docs/assets/.
+func registerDocs(mux *http.ServeMux) {
+	sub, err := fs.Sub(docsFS, "docsui")
+	if err != nil {
+		panic("api: embedded docs missing: " + err.Error()) // the embed directive guarantees the directory
+	}
+	page, err := fs.ReadFile(sub, "index.html")
+	if err != nil {
+		panic("api: embedded docs page missing: " + err.Error())
+	}
+	mux.HandleFunc("GET /docs", func(w http.ResponseWriter, _ *http.Request) {
+		w.Header().Set("Content-Type", "text/html; charset=utf-8")
+		_, _ = w.Write(page)
+	})
+	mux.Handle("GET /docs/assets/", http.StripPrefix("/docs/assets/", http.FileServerFS(sub)))
+}

internal/api/docsui/LICENSE

@@ -0,0 +1,202 @@
+
+                                 Apache License
+                           Version 2.0, January 2004
+                        http://www.apache.org/licenses/
+
+   TERMS AND CONDITIONS FOR USE, REPRODUCTION, AND DISTRIBUTION
+
+   1. Definitions.
+
+      "License" shall mean the terms and conditions for use, reproduction,
+      and distribution as defined by Sections 1 through 9 of this document.
+
+      "Licensor" shall mean the copyright owner or entity authorized by
+      the copyright owner that is granting the License.
+
+      "Legal Entity" shall mean the union of the acting entity and all
+      other entities that control, are controlled by, or are under common
+      control with that entity. For the purposes of this definition,
+      "control" means (i) the power, direct or indirect, to cause the
+      direction or management of such entity, whether by contract or
+      otherwise, or (ii) ownership of fifty percent (50%) or more of the
+      outstanding shares, or (iii) beneficial ownership of such entity.
+
+      "You" (or "Your") shall mean an individual or Legal Entity
+      exercising permissions granted by this License.
+
+      "Source" form shall mean the preferred form for making modifications,
+      including but not limited to software source code, documentation
+      source, and configuration files.
+
+      "Object" form shall mean any form resulting from mechanical
+      transformation or translation of a Source form, including but
+      not limited to compiled object code, generated documentation,
+      and conversions to other media types.
+
+      "Work" shall mean the work of authorship, whether in Source or
+      Object form, made available under the License, as indicated by a
+      copyright notice that is included in or attached to the work
+      (an example is provided in the Appendix below).
+
+      "Derivative Works" shall mean any work, whether in Source or Object
+      form, that is based on (or derived from) the Work and for which the
+      editorial revisions, annotations, elaborations, or other modifications
+      represent, as a whole, an original work of authorship. For the purposes
+      of this License, Derivative Works shall not include works that remain
+      separable from, or merely link (or bind by name) to the interfaces of,
+      the Work and Derivative Works thereof.
+
+      "Contribution" shall mean any work of authorship, including
+      the original version of the Work and any modifications or additions
+      to that Work or Derivative Works thereof, that is intentionally
+      submitted to Licensor for inclusion in the Work by the copyright owner
+      or by an individual or Legal Entity authorized to submit on behalf of
+      the copyright owner. For the purposes of this definition, "submitted"
+      means any form of electronic, verbal, or written communication sent
+      to the Licensor or its representatives, including but not limited to
+      communication on electronic mailing lists, source code control systems,
+      and issue tracking systems that are managed by, or on behalf of, the
+      Licensor for the purpose of discussing and improving the Work, but
+      excluding communication that is conspicuously marked or otherwise
+      designated in writing by the copyright owner as "Not a Contribution."
+
+      "Contributor" shall mean Licensor and any individual or Legal Entity
+      on behalf of whom a Contribution has been received by Licensor and
+      subsequently incorporated within the Work.
+
+   2. Grant of Copyright License. Subject to the terms and conditions of
+      this License, each Contributor hereby grants to You a perpetual,
+      worldwide, non-exclusive, no-charge, royalty-free, irrevocable
+      copyright license to reproduce, prepare Derivative Works of,
+      publicly display, publicly perform, sublicense, and distribute the
+      Work and such Derivative Works in Source or Object form.
+
+   3. Grant of Patent License. Subject to the terms and conditions of
+      this License, each Contributor hereby grants to You a perpetual,
+      worldwide, non-exclusive, no-charge, royalty-free, irrevocable
+      (except as stated in this section) patent license to make, have made,
+      use, offer to sell, sell, import, and otherwise transfer the Work,
+      where such license applies only to those patent claims licensable
+      by such Contributor that are necessarily infringed by their
+      Contribution(s) alone or by combination of their Contribution(s)
+      with the Work to which such Contribution(s) was submitted. If You
+      institute patent litigation against any entity (including a
+      cross-claim or counterclaim in a lawsuit) alleging that the Work
+      or a Contribution incorporated within the Work constitutes direct
+      or contributory patent infringement, then any patent licenses
+      granted to You under this License for that Work shall terminate
+      as of the date such litigation is filed.
+
+   4. Redistribution. You may reproduce and distribute copies of the
+      Work or Derivative Works thereof in any medium, with or without
+      modifications, and in Source or Object form, provided that You
+      meet the following conditions:
+
+      (a) You must give any other recipients of the Work or
+          Derivative Works a copy of this License; and
+
+      (b) You must cause any modified files to carry prominent notices
+          stating that You changed the files; and
+
+      (c) You must retain, in the Source form of any Derivative Works
+          that You distribute, all copyright, patent, trademark, and
+          attribution notices from the Source form of the Work,
+          excluding those notices that do not pertain to any part of
+          the Derivative Works; and
+
+      (d) If the Work includes a "NOTICE" text file as part of its
+          distribution, then any Derivative Works that You distribute must
+          include a readable copy of the attribution notices contained
+          within such NOTICE file, excluding those notices that do not
+          pertain to any part of the Derivative Works, in at least one
+          of the following places: within a NOTICE text file distributed
+          as part of the Derivative Works; within the Source form or
+          documentation, if provided along with the Derivative Works; or,
+          within a display generated by the Derivative Works, if and
+          wherever such third-party notices normally appear. The contents
+          of the NOTICE file are for informational purposes only and
+          do not modify the License. You may add Your own attribution
+          notices within Derivative Works that You distribute, alongside
+          or as an addendum to the NOTICE text from the Work, provided
+          that such additional attribution notices cannot be construed
+          as modifying the License.
+
+      You may add Your own copyright statement to Your modifications and
+      may provide additional or different license terms and conditions
+      for use, reproduction, or distribution of Your modifications, or
+      for any such Derivative Works as a whole, provided Your use,
+      reproduction, and distribution of the Work otherwise complies with
+      the conditions stated in this License.
+
+   5. Submission of Contributions. Unless You explicitly state otherwise,
+      any Contribution intentionally submitted for inclusion in the Work
+      by You to the Licensor shall be under the terms and conditions of
+      this License, without any additional terms or conditions.
+      Notwithstanding the above, nothing herein shall supersede or modify
+      the terms of any separate license agreement you may have executed
+      with Licensor regarding such Contributions.
+
+   6. Trademarks. This License does not grant permission to use the trade
+      names, trademarks, service marks, or product names of the Licensor,
+      except as required for reasonable and customary use in describing the
+      origin of the Work and reproducing the content of the NOTICE file.
+
+   7. Disclaimer of Warranty. Unless required by applicable law or
+      agreed to in writing, Licensor provides the Work (and each
+      Contributor provides its Contributions) on an "AS IS" BASIS,
+      WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or
+      implied, including, without limitation, any warranties or conditions
+      of TITLE, NON-INFRINGEMENT, MERCHANTABILITY, or FITNESS FOR A
+      PARTICULAR PURPOSE. You are solely responsible for determining the
+      appropriateness of using or redistributing the Work and assume any
+      risks associated with Your exercise of permissions under this License.
+
+   8. Limitation of Liability. In no event and under no legal theory,
+      whether in tort (including negligence), contract, or otherwise,
+      unless required by applicable law (such as deliberate and grossly
+      negligent acts) or agreed to in writing, shall any Contributor be
+      liable to You for damages, including any direct, indirect, special,
+      incidental, or consequential damages of any character arising as a
+      result of this License or out of the use or inability to use the
+      Work (including but not limited to damages for loss of goodwill,
+      work stoppage, computer failure or malfunction, or any and all
+      other commercial damages or losses), even if such Contributor
+      has been advised of the possibility of such damages.
+
+   9. Accepting Warranty or Additional Liability. While redistributing
+      the Work or Derivative Works thereof, You may choose to offer,
+      and charge a fee for, acceptance of support, warranty, indemnity,
+      or other liability obligations and/or rights consistent with this
+      License. However, in accepting such obligations, You may act only
+      on Your own behalf and on Your sole responsibility, not on behalf
+      of any other Contributor, and only if You agree to indemnify,
+      defend, and hold each Contributor harmless for any liability
+      incurred by, or claims asserted against, such Contributor by reason
+      of your accepting any such warranty or additional liability.
+
+   END OF TERMS AND CONDITIONS
+
+   APPENDIX: How to apply the Apache License to your work.
+
+      To apply the Apache License to your work, attach the following
+      boilerplate notice, with the fields enclosed by brackets "[]"
+      replaced with your own identifying information. (Don't include
+      the brackets!)  The text should be enclosed in the appropriate
+      comment syntax for the file format. We also recommend that a
+      file or class name and description of purpose be included on the
+      same "printed page" as the copyright notice for easier
+      identification within third-party archives.
+
+   Copyright [yyyy] [name of copyright owner]
+
+   Licensed under the Apache License, Version 2.0 (the "License");
+   you may not use this file except in compliance with the License.
+   You may obtain a copy of the License at
+
+       http://www.apache.org/licenses/LICENSE-2.0
+
+   Unless required by applicable law or agreed to in writing, software
+   distributed under the License is distributed on an "AS IS" BASIS,
+   WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+   See the License for the specific language governing permissions and
+   limitations under the License.

internal/api/docsui/NOTICE

@@ -0,0 +1,2 @@
+swagger-ui
+Copyright 2020-2021 SmartBear Software Inc.

internal/api/docsui/index.html

@@ -0,0 +1,14 @@
+<!doctype html>
+<html lang="en">
+<head>
+<meta charset="utf-8">
+<meta name="viewport" content="width=device-width, initial-scale=1">
+<title>nmon API</title>
+<link rel="stylesheet" href="/docs/assets/swagger-ui.css">
+</head>
+<body>
+<div id="swagger-ui"></div>
+<script src="/docs/assets/swagger-ui-bundle.js"></script>
+<script src="/docs/assets/init.js"></script>
+</body>
+</html>

internal/api/docsui/init.js

@@ -0,0 +1 @@
+window.ui = SwaggerUIBundle({ url: '/openapi.json', dom_id: '#swagger-ui', deepLinking: true });

internal/api/errors_test.go

@@ -1,7 +1,9 @@
 package api
 
 import (
+	"errors"
 	"fmt"
+	"net/http"
 	"testing"
 
 	"github.com/danielgtaylor/huma/v2"
@@ -17,11 +19,12 @@ func TestStoreErrorMapping(t *testing.T) {
 		status int
 		detail string
 	}{
-		{fmt.Errorf("%w: slug taken", store.ErrConflict), 409, "slug taken"},
-		{fmt.Errorf("%w: bad kind", store.ErrInvalid), 422, "bad kind"},
-		{fmt.Errorf("wrapped: %w", store.ErrNotFound), 404, "not found"},
+		{fmt.Errorf("%w: slug taken", store.ErrConflict), http.StatusConflict, "slug taken"},
+		{fmt.Errorf("%w: bad kind", store.ErrInvalid), http.StatusUnprocessableEntity, "bad kind"},
+		{fmt.Errorf("wrapped: %w", store.ErrNotFound), http.StatusNotFound, "not found"},
 	} {
-		se, ok := s.storeErr(tc.err).(huma.StatusError)
+		var se huma.StatusError
+		ok := errors.As(s.storeErr(tc.err), &se)
 		if !ok || se.GetStatus() != tc.status || se.Error() != tc.detail {
 			t.Errorf("%v: got %v, want %d %q", tc.err, se, tc.status, tc.detail)
 		}

internal/api/graph.go

@@ -0,0 +1,142 @@
+package api
+
+import (
+	"context"
+	"net/http"
+	"time"
+
+	"github.com/danielgtaylor/huma/v2"
+
+	"github.com/v10networks/nmon/internal/store"
+)
+
+func (s *server) registerGraph(api huma.API) {
+	huma.Register(api, huma.Operation{
+		OperationID: "get-graph", Method: http.MethodGet, Path: "/api/v1/graph", Tags: []string{"graph"},
+		Summary: "Bits per second in and out of one interface",
+		Description: "From the hot store when the range lies within hot retention; older data comes from the long store's " +
+			"hourly rollups, and a range that needs both is stitched at stitched_at. Stretches with no data in either store " +
+			"are listed in partial. An unreliable interface returns no series. max=true adds the per-step maximum; " +
+			"p95=true adds the 95th percentile of 5-minute averages, computed live.",
+		Errors: []int{http.StatusNotFound, http.StatusUnprocessableEntity, http.StatusTooManyRequests, http.StatusServiceUnavailable},
+	}, s.graph)
+}
+
+type graphIn struct {
+	Iface string    `query:"iface" required:"true" minLength:"1" doc:"Interface ULID."`
+	From  time.Time `query:"from" doc:"Start, RFC 3339. Default one hour before to."`
+	To    time.Time `query:"to" doc:"End, RFC 3339. Default now."`
+	Step  int64     `query:"step" minimum:"1" doc:"Step in seconds. Default max(60, range/1000) rounded up to whole minutes."`
+	Dir   string    `query:"dir" enum:"in,out" doc:"Only this direction; the other series is empty."`
+	Max   bool      `query:"max" doc:"Also return in_max and out_max, the highest one-minute rate within each step."`
+	P95   bool      `query:"p95" doc:"Also return the live 95th percentile of 5-minute averages."`
+}
+
+func (s *server) graph(ctx context.Context, in *graphIn) (*struct{ Body GraphResponse }, error) {
+	i, err := s.Store.GetInterface(ctx, in.Iface)
+	if err != nil {
+		return nil, s.storeErr(err)
+	}
+	dev, err := s.Store.GetDeviceByID(ctx, i.DeviceID)
+	if err != nil {
+		return nil, s.storeErr(err)
+	}
+	from, to, err := s.graphRange(in)
+	if err != nil {
+		return nil, err
+	}
+	resp := GraphResponse{
+		Iface: GraphIface{
+			ID: i.ID, IfName: i.IfName, IfAlias: i.IfAlias, SpeedBPS: speedBPS(i), Device: DeviceRef{Slug: dev.Slug, Name: dev.Name},
+		},
+		Partial: []TimeSpan{}, Series: GraphSeries{In: []Point{}, Out: []Point{}},
+	}
+	hotStart := s.Clock.Now().Add(-s.HotRetention)
+	plan, err := planGraph(from, to, hotStart, time.Duration(in.Step)*time.Second)
+	if err != nil {
+		return nil, huma.Error422UnprocessableEntity(err.Error())
+	}
+	resp.StepSeconds, resp.Tier = int64(plan.newest().step/time.Second), plan.newest().tier
+	if i.Unreliable {
+		resp.Unreliable, resp.UnreliableReason = true, unreliableReason(i)
+		return &struct{ Body GraphResponse }{resp}, nil
+	}
+	if err := s.fillGraph(ctx, &resp, i, plan, in, hotStart); err != nil {
+		return nil, err
+	}
+	return &struct{ Body GraphResponse }{resp}, nil
+}
+
+// graphRange applies the defaults and validates the requested range.
+func (s *server) graphRange(in *graphIn) (from, to time.Time, err error) {
+	to = in.To
+	if to.IsZero() {
+		to = s.Clock.Now()
+	}
+	from = in.From
+	if from.IsZero() {
+		from = to.Add(-time.Hour)
+	}
+	if !from.Before(to) {
+		return from, to, huma.Error422UnprocessableEntity("from must be before to")
+	}
+	return from.UTC(), to.UTC(), nil
+}
+
+// fillGraph queries the stores the plan names and lays the samples out on the grid.
+func (s *server) fillGraph(
+	ctx context.Context, resp *GraphResponse, i *store.Interface, p *graphPlan, in *graphIn, hotStart time.Time,
+) error {
+	release, err := s.admit(ctx, false)
+	if err != nil {
+		return err
+	}
+	defer release()
+	qctx, cancel := context.WithTimeout(ctx, QueryTimeout)
+	defer cancel()
+	q := &graphQuery{iface: i, dirs: []string{dirIn, dirOut}, withMax: in.Max}
+	if in.Dir != "" {
+		q.dirs = []string{in.Dir}
+	}
+	data := newGraphData()
+	for _, w := range p.tiers {
+		if err := s.fetchTier(qctx, q, w, data); err != nil {
+			return err
+		}
+	}
+	assemble(resp, p, q, data)
+	if in.P95 {
+		p95, err := s.livep95(qctx, q, p, hotStart)
+		if err != nil {
+			return err
+		}
+		resp.P95 = p95
+	}
+	return nil
+}
+
+// assemble turns the samples into series, tiers, stitched_at and partial spans.
+func assemble(resp *GraphResponse, p *graphPlan, q *graphQuery, d *graphData) {
+	grid := gridOf(p)
+	for _, dir := range q.dirs {
+		resp.Series.set(dir, false, pointsOf(grid, d.avg[dir]))
+		if q.withMax {
+			resp.Series.set(dir, true, pointsOf(grid, d.max[dir]))
+		}
+	}
+	has := func(ts int64) bool {
+		for _, dir := range q.dirs {
+			if _, ok := d.avg[dir][ts]; ok {
+				return true
+			}
+		}
+		return false
+	}
+	resp.Partial = append(resp.Partial, findGaps(grid, has, p.from.Unix(), p.to.Unix())...)
+	if p.stitchedAt != nil {
+		resp.StitchedAt = p.stitchedAt
+		for _, w := range p.tiers {
+			resp.Tiers = append(resp.Tiers, GraphTier{From: w.from.UTC(), To: w.bound.UTC(), Tier: w.tier, StepSeconds: int64(w.step / time.Second)})
+		}
+	}
+}

internal/api/graph_fetch.go

@@ -0,0 +1,163 @@
+package api
+
+import (
+	"context"
+	"errors"
+	"fmt"
+	"strconv"
+	"time"
+
+	"github.com/v10networks/nmon/internal/store"
+	"github.com/v10networks/nmon/internal/vmsup"
+)
+
+const (
+	dirIn  = "in"
+	dirOut = "out"
+	// minRateWindow keeps the rate window above two poll intervals so a step of
+	// one minute still sees two samples.
+	minRateWindow = 2 * time.Minute
+	// maxInnerStep is the resolution of the max-over-step subquery.
+	maxInnerStep = time.Minute
+)
+
+// graphData holds the samples found, by direction and Unix second.
+type graphData struct {
+	avg map[string]map[int64]float64
+	max map[string]map[int64]float64
+}
+
+func newGraphData() *graphData {
+	return &graphData{avg: map[string]map[int64]float64{}, max: map[string]map[int64]float64{}}
+}
+
+func (g *graphData) put(isMax bool, dir string, ts int64, v float64) {
+	m := g.avg
+	if isMax {
+		m = g.max
+	}
+	if m[dir] == nil {
+		m[dir] = map[int64]float64{}
+	}
+	if old, ok := m[dir][ts]; !ok || v > old {
+		m[dir][ts] = v // stores agree on duplicates; the highest wins
+	}
+}
+
+// graphQuery is what one fetch needs to know.
+type graphQuery struct {
+	iface   *store.Interface
+	dirs    []string
+	withMax bool
+}
+
+// octets is the counter that carries direction dir for the interface.
+func (q *graphQuery) octets(dir string) string {
+	switch {
+	case q.iface.HasHCCounters && dir == dirIn:
+		return "ifHCInOctets"
+	case q.iface.HasHCCounters:
+		return "ifHCOutOctets"
+	case dir == dirIn:
+		return "ifInOctets"
+	}
+	return "ifOutOctets"
+}
+
+func secs(d time.Duration) string { return strconv.FormatInt(int64(d/time.Second), 10) + "s" }
+
+// rawExpr is the average bits per second of dir over the rate window.
+func (q *graphQuery) rawExpr(dir string, step time.Duration) string {
+	sel := q.octets(dir) + `{iface=` + quote(q.iface.ID) + `}`
+	return `rate(` + sel + `[` + secs(max(step, minRateWindow)) + `])*8`
+}
+
+// rawMaxExpr is the highest one-minute rate seen within each step.
+func (q *graphQuery) rawMaxExpr(dir string, step time.Duration) string {
+	sel := q.octets(dir) + `{iface=` + quote(q.iface.ID) + `}`
+	return `max_over_time((rate(` + sel + `[` + secs(maxInnerStep) + `])*8)[` + secs(step) + `:` + secs(maxInnerStep) + `])`
+}
+
+// longExpr reads an hourly rollup metric. Versions of a rewritten window share
+// the same value, so max by (dir) collapses them; a coarser step averages (or
+// takes the max of) the hours it covers.
+func (q *graphQuery) longExpr(metric, over string, dir string, step time.Duration) string {
+	inner := `max by (dir) (` + metric + `{iface=` + quote(q.iface.ID) + `,dir=` + quote(dir) + `})`
+	if step <= longStepMin {
+		return inner
+	}
+	return over + `((` + inner + `)[` + secs(step) + `:` + secs(longStepMin) + `])`
+}
+
+// fetchTier fills d from the store that owns the tier. Hot errors fail the
+// graph; a long store that is down only leaves its stretch empty, which the
+// response reports as partial.
+func (s *server) fetchTier(ctx context.Context, q *graphQuery, w tierWindow, d *graphData) error {
+	storeName := "hot"
+	if w.tier == tier1h {
+		storeName = "long"
+	}
+	for _, dir := range q.dirs {
+		for _, wantMax := range []bool{false, true} {
+			if wantMax && !q.withMax {
+				continue
+			}
+			err := s.fetchOne(ctx, storeName, q.exprFor(w, dir, wantMax), w, func(ts int64, v float64) { d.put(wantMax, dir, ts, v) })
+			if err == nil {
+				continue
+			}
+			if storeName == "long" && !errors.Is(err, context.Canceled) {
+				s.Logger.Warn("long store query failed; its stretch is reported partial", "err", err)
+				continue
+			}
+			return err
+		}
+	}
+	return nil
+}
+
+func (q *graphQuery) exprFor(w tierWindow, dir string, wantMax bool) string {
+	switch {
+	case w.tier == tierRaw && wantMax:
+		return q.rawMaxExpr(dir, w.step)
+	case w.tier == tierRaw:
+		return q.rawExpr(dir, w.step)
+	case wantMax:
+		return q.longExpr("nmon_if_rate_bps_max_1h", "max_over_time", dir, w.step)
+	}
+	return q.longExpr("nmon_if_rate_bps_avg_1h", "avg_over_time", dir, w.step)
+}
+
+// fetchOne runs one range query over the tier's window and hands every finite sample to add.
+func (s *server) fetchOne(ctx context.Context, storeName, expr string, w tierWindow, add func(ts int64, v float64)) error {
+	body, err := s.Querier.QueryRange(ctx, storeName, expr, w.from, w.last, w.step)
+	if err != nil {
+		return s.vmErr(ctx, err)
+	}
+	rows, err := parseVM(body)
+	if err != nil {
+		return fmt.Errorf("graph: %w", err)
+	}
+	for _, r := range rows {
+		for _, p := range r.Values {
+			if p.OK {
+				add(p.TS, p.V)
+			}
+		}
+	}
+	return nil
+}
+
+// vmErr maps a metric-store failure to a problem. It is shared by /query and /graph.
+func (s *server) vmErr(ctx context.Context, err error) error {
+	switch {
+	case errors.Is(err, vmsup.ErrStoreDown):
+		return errStoreDown()
+	case errors.Is(err, context.DeadlineExceeded) || errors.Is(ctx.Err(), context.DeadlineExceeded):
+		return errQueryTimeout()
+	case isBadQuery(err):
+		return badQuery(err)
+	}
+	s.Logger.Warn("query failed", "err", err)
+	return errStoreFailed()
+}

internal/api/graph_internal_test.go

@@ -0,0 +1,160 @@
+package api
+
+import (
+	"math"
+	"testing"
+	"time"
+)
+
+func TestDefaultStepIsMaxOf60sAndRangeOver1000RoundedToMinutes(t *testing.T) {
+	for rng, want := range map[time.Duration]time.Duration{
+		time.Hour: time.Minute, 16 * time.Hour: time.Minute, 17 * time.Hour: 2 * time.Minute,
+		24 * time.Hour: 2 * time.Minute, 30 * 24 * time.Hour: 44 * time.Minute, 365 * 24 * time.Hour: 526 * time.Minute,
+	} {
+		if got := defaultStep(rng); got != want {
+			t.Errorf("defaultStep(%s) = %s, want %s", rng, got, want)
+		}
+	}
+}
+
+func TestPlanGraphTiers(t *testing.T) {
+	now := time.Date(2026, 10, 22, 12, 0, 0, 0, time.UTC)
+	hotStart := now.Add(-30 * 24 * time.Hour)
+	cases := []struct {
+		name       string
+		from, to   time.Time
+		tiers      []string
+		stitched   bool
+		wantErr    bool
+		step       time.Duration
+		newestStep time.Duration
+	}{
+		{"1h", now.Add(-time.Hour), now, []string{"raw"}, false, false, 0, time.Minute},
+		{"exactly the hot window", hotStart, now, []string{"raw"}, false, false, 0, 44 * time.Minute},
+		{"a hair beyond hot is still raw", hotStart.Add(-20 * time.Minute), now, []string{"raw"}, false, false, 0, 44 * time.Minute},
+		{"straddles", now.Add(-40 * 24 * time.Hour), now, []string{"1h", "raw"}, true, false, 0, 58 * time.Minute},
+		{"ends inside hot start", now.Add(-60 * 24 * time.Hour), hotStart, []string{"1h"}, false, false, 0, time.Hour},
+		{"old", now.Add(-90 * 24 * time.Hour), now.Add(-60 * 24 * time.Hour), []string{"1h"}, false, false, 0, time.Hour},
+		{"too many points", now.Add(-30 * 24 * time.Hour), now, nil, false, true, time.Second, 0},
+		{"explicit step", now.Add(-time.Hour), now, []string{"raw"}, false, false, 5 * time.Minute, 5 * time.Minute},
+	}
+	for _, tc := range cases {
+		p, err := planGraph(tc.from, tc.to, hotStart, tc.step)
+		if (err != nil) != tc.wantErr {
+			t.Errorf("%s: err %v", tc.name, err)
+			continue
+		}
+		if tc.wantErr {
+			continue
+		}
+		var got []string
+		for _, w := range p.tiers {
+			got = append(got, w.tier)
+		}
+		if len(got) != len(tc.tiers) || (p.stitchedAt != nil) != tc.stitched || p.newest().step != tc.newestStep {
+			t.Errorf("%s: tiers %v stitched %v newest step %s, want %v %v %s", tc.name, got, p.stitchedAt, p.newest().step, tc.tiers, tc.stitched, tc.newestStep)
+			continue
+		}
+		for i := range got {
+			if got[i] != tc.tiers[i] {
+				t.Errorf("%s: tiers %v, want %v", tc.name, got, tc.tiers)
+			}
+		}
+		if tc.stitched {
+			join := *p.stitchedAt
+			if join.Before(hotStart) || join.Sub(hotStart) >= p.newest().step || join.Unix()%int64(p.newest().step/time.Second) != 0 {
+				t.Errorf("%s: join %v", tc.name, join)
+			}
+			if long := p.tiers[0]; long.last.Unix() >= join.Unix() || long.bound != join {
+				t.Errorf("%s: long tier overlaps raw: %+v", tc.name, long)
+			}
+		}
+	}
+}
+
+func TestFindGapsThresholdIsTwoSteps(t *testing.T) {
+	grid := make([]slot, 11)
+	for i := range grid {
+		grid[i] = slot{ts: int64(i * 60), step: 60}
+	}
+	has := func(missing ...int) func(int64) bool {
+		return func(ts int64) bool {
+			for _, m := range missing {
+				if ts == int64(m*60) {
+					return false
+				}
+			}
+			return true
+		}
+	}
+	for _, tc := range []struct {
+		name    string
+		missing []int
+		want    [][2]int64
+	}{
+		{"complete", nil, nil},
+		{"one missing sample", []int{4}, nil},
+		{"two missing samples", []int{4, 5}, [][2]int64{{180, 360}}},
+		{"leading", []int{0, 1, 2}, [][2]int64{{0, 180}}},
+		{"leading short", []int{0, 1}, nil},
+		{"trailing", []int{8, 9, 10}, [][2]int64{{420, 600}}},
+		{"two separate holes", []int{2, 3, 7, 8}, [][2]int64{{60, 240}, {360, 540}}},
+	} {
+		got := findGaps(grid, has(tc.missing...), 0, 600)
+		if len(got) != len(tc.want) {
+			t.Errorf("%s: %v, want %v", tc.name, got, tc.want)
+			continue
+		}
+		for i, g := range got {
+			if g.From.Unix() != tc.want[i][0] || g.To.Unix() != tc.want[i][1] {
+				t.Errorf("%s: gap %d is %v..%v, want %v", tc.name, i, g.From.Unix(), g.To.Unix(), tc.want[i])
+			}
+		}
+	}
+	none := func(int64) bool { return false }
+	if g := findGaps(grid, none, 0, 600); len(g) != 1 || g[0].From.Unix() != 0 || g[0].To.Unix() != 600 {
+		t.Errorf("no data: %v", g)
+	}
+	if g := findGaps(nil, none, 0, 0); g != nil {
+		t.Errorf("empty grid: %v", g)
+	}
+}
+
+func TestNearestRank(t *testing.T) {
+	seq := func(n int) []float64 {
+		out := make([]float64, n)
+		for i := range out {
+			out[i] = float64(n - i) // descending, so sorting matters
+		}
+		return out
+	}
+	for n, want := range map[int]float64{1: 1, 2: 2, 19: 19, 20: 19, 21: 20, 100: 95, 101: 96, 1000: 950} {
+		if got := nearestRank(seq(n), 0.95); got != want {
+			t.Errorf("p95 of 1..%d = %v, want %v", n, got, want)
+		}
+	}
+	if !math.IsNaN(nearestRank(nil, 0.95)) {
+		t.Error("no values should be NaN")
+	}
+	in := []float64{3, 1, 2}
+	nearestRank(in, 0.5)
+	if in[0] != 3 {
+		t.Error("input must not be reordered")
+	}
+}
+
+func TestParentCycleHelpersAndEvidence(t *testing.T) {
+	got := evidenceLines(`{"b":2,"a":"x","c":["y"]}`)
+	if len(got) != 3 || got[0] != "a: x" || got[1] != "b: 2" || got[2] != `c: ["y"]` {
+		t.Errorf("evidence: %q", got)
+	}
+	if got := evidenceLines(`not json`); len(got) != 1 || got[0] != "not json" {
+		t.Errorf("evidence fallback: %q", got)
+	}
+	if got := evidenceLines(``); got == nil || len(got) != 0 {
+		t.Errorf("empty evidence must be [] not nil: %#v", got)
+	}
+	if quote(`a"b\c`) != `"a\"b\\c"` {
+		t.Errorf("quote: %s", quote(`a"b\c`))
+	}
+}

internal/api/graph_p95.go

@@ -0,0 +1,64 @@
+package api
+
+import (
+	"context"
+	"time"
+)
+
+const (
+	p95Quantile = 0.95
+	p95Slot     = 5 * time.Minute
+	// maxP95Span bounds the live computation to what one range query can return (about 25,000 slots).
+	maxP95Span = 85 * 24 * time.Hour
+)
+
+// livep95 computes the 95th percentile of 5-minute average rates over the
+// raw (hot) part of the drawn range, by nearest rank. M5 adds the materialised
+// monthly value; until then the source is "live" and coverage says how much of
+// the range's 5-minute slots had data, so a short history never passes for a full month.
+func (s *server) livep95(ctx context.Context, q *graphQuery, p *graphPlan, hotStart time.Time) (*GraphP95, error) {
+	raw := p.newest()
+	if raw.tier != tierRaw {
+		return &GraphP95{Source: "live"}, nil
+	}
+	start := ceilTo(latest(raw.from, hotStart, raw.bound.Add(-maxP95Span)), p95Slot)
+	end := floorTo(raw.bound, p95Slot)
+	expected := max(int64(p.to.Sub(p.from)/p95Slot), 1)
+	out := &GraphP95{Source: "live"}
+	if end.Before(start) {
+		return out, nil
+	}
+	w := tierWindow{tier: tierRaw, from: start, last: end, bound: end, step: p95Slot}
+	coverage := 1.0
+	for _, dir := range q.dirs {
+		var vals []float64
+		expr := `rate(` + q.octets(dir) + `{iface=` + quote(q.iface.ID) + `}[` + secs(p95Slot) + `])*8`
+		err := s.fetchOne(ctx, "hot", expr, w, func(_ int64, v float64) { vals = append(vals, v) })
+		if err != nil {
+			return nil, err
+		}
+		coverage = min(coverage, float64(len(vals))/float64(expected))
+		if len(vals) == 0 {
+			continue
+		}
+		v := nearestRank(vals, p95Quantile)
+		if dir == dirIn {
+			out.InBPS = &v
+		} else {
+			out.OutBPS = &v
+		}
+	}
+	out.Coverage = min(coverage, 1)
+	return out, nil
+}
+
+// latest returns the latest of ts.
+func latest(ts ...time.Time) time.Time {
+	out := ts[0]
+	for _, t := range ts[1:] {
+		if t.After(out) {
+			out = t
+		}
+	}
+	return out
+}

internal/api/graph_plan.go

@@ -0,0 +1,119 @@
+package api
+
+import (
+	"errors"
+	"fmt"
+	"time"
+)
+
+const (
+	// maxGraphPoints bounds the points per series; the metric store caps a range query near 30,000.
+	maxGraphPoints = 11_000
+	// minRawStep is the default floor of a raw step: one poll interval.
+	minRawStep = 60 * time.Second
+	// targetPoints is how many points the default step aims for.
+	targetPoints = 1000
+	// longStepMin is the resolution of the long store's hourly rollup.
+	longStepMin = time.Hour
+)
+
+var errTooManyPoints = errors.New("too many points")
+
+// tierWindow is one stretch of a graph answered by one store: points at
+// from, from+step, ... up to and including last. bound is where the tier
+// officially ends (the join for the older tier of a stitched graph).
+type tierWindow struct {
+	tier  string
+	from  time.Time
+	last  time.Time
+	bound time.Time
+	step  time.Duration
+}
+
+// graphPlan says which stores answer which part of [from, to]. Tiers are oldest first.
+type graphPlan struct {
+	from, to   time.Time // aligned bounds of the whole graph
+	tiers      []tierWindow
+	stitchedAt *time.Time
+}
+
+func (p *graphPlan) newest() tierWindow { return p.tiers[len(p.tiers)-1] }
+
+// floorTo rounds t down to a multiple of d, counted from the Unix epoch so that
+// panning a graph never shifts its sample times.
+func floorTo(t time.Time, d time.Duration) time.Time {
+	ds := int64(d / time.Second)
+	return time.Unix(floorDiv(t.Unix(), ds)*ds, 0).UTC()
+}
+
+func ceilTo(t time.Time, d time.Duration) time.Time {
+	f := floorTo(t, d)
+	if f.Equal(t) {
+		return f
+	}
+	return f.Add(d)
+}
+
+func floorDiv(a, b int64) int64 {
+	q := a / b
+	if a%b != 0 && (a < 0) != (b < 0) {
+		q--
+	}
+	return q
+}
+
+// defaultStep is max(60 s, range/1000) rounded up to whole minutes, so the
+// same range always lands on the same grid.
+func defaultStep(rng time.Duration) time.Duration {
+	return max(minRawStep, ceilDur(rng/targetPoints, minRawStep))
+}
+
+func ceilDur(d, unit time.Duration) time.Duration {
+	return (d + unit - 1) / unit * unit
+}
+
+// planGraph decides the tiers for [from, to] at the given step (0: default).
+// hotStart is where the hot store's retention begins. A range that lies within
+// hot (give or take one step) is answered by raw data alone, a range wholly
+// older than hot by hourly data alone, and one that straddles hotStart is
+// stitched: hourly before the join, raw from it.
+func planGraph(from, to, hotStart time.Time, step time.Duration) (*graphPlan, error) {
+	if step <= 0 {
+		step = defaultStep(to.Sub(from))
+	}
+	if n := to.Sub(from) / step; n > maxGraphPoints {
+		return nil, fmt.Errorf("%w: %d points at a %s step; the limit is %d, use a larger step", errTooManyPoints, n, step, maxGraphPoints)
+	}
+	fromRaw, toRaw := floorTo(from, step), floorTo(to, step)
+	long := max(longStepMin, ceilDur(step, longStepMin))
+	switch {
+	case !fromRaw.Add(step).Before(hotStart):
+		return &graphPlan{from: fromRaw, to: toRaw, tiers: []tierWindow{
+			{tier: tierRaw, from: fromRaw, last: toRaw, bound: toRaw, step: step},
+		}}, nil
+	case !toRaw.After(hotStart):
+		fl, tl := floorTo(from, long), floorTo(to, long)
+		return &graphPlan{from: fl, to: tl, tiers: []tierWindow{
+			{tier: tier1h, from: fl, last: tl, bound: tl, step: long},
+		}}, nil
+	}
+	join := ceilTo(hotStart, step)
+	fl := floorTo(from, long)
+	return &graphPlan{from: fl, to: toRaw, stitchedAt: &join, tiers: []tierWindow{
+		{tier: tier1h, from: fl, last: floorTo(join.Add(-time.Nanosecond), long), bound: join, step: long},
+		{tier: tierRaw, from: join, last: toRaw, bound: toRaw, step: step},
+	}}, nil
+}
+
+// slots lists the sample times of a tier.
+func (w tierWindow) slots() []int64 {
+	if w.last.Before(w.from) {
+		return nil
+	}
+	n := int(w.last.Sub(w.from)/w.step) + 1
+	out := make([]int64, 0, n)
+	for t := w.from; !t.After(w.last); t = t.Add(w.step) {
+		out = append(out, t.Unix())
+	}
+	return out
+}

internal/api/graph_series.go

@@ -0,0 +1,80 @@
+package api
+
+import (
+	"math"
+	"sort"
+	"time"
+)
+
+// gapFactor is how many steps without data make a stretch "partial".
+const gapFactor = 2
+
+// slot is one sample time of the graph and the step of the tier it belongs to.
+type slot struct {
+	ts   int64
+	step int64
+}
+
+// gridOf lists every sample time of the plan, oldest first.
+func gridOf(p *graphPlan) []slot {
+	var out []slot
+	for _, w := range p.tiers {
+		step := int64(w.step / time.Second)
+		for _, ts := range w.slots() {
+			out = append(out, slot{ts: ts, step: step})
+		}
+	}
+	return out
+}
+
+// pointsOf lays vals over the grid; a slot without data is a null point.
+func pointsOf(grid []slot, vals map[int64]float64) []Point {
+	out := make([]Point, len(grid))
+	for i, g := range grid {
+		out[i] = Point{TS: g.ts}
+		if v, ok := vals[g.ts]; ok {
+			x := v
+			out[i].V = &x
+		}
+	}
+	return out
+}
+
+// findGaps returns the stretches of [start, end] longer than gapFactor steps in
+// which no slot has data. A stretch runs from the last slot with data (or the
+// start) to the next one (or the end); its step is the larger of its two
+// neighbours', so a join between tiers does not report a false gap.
+func findGaps(grid []slot, has func(ts int64) bool, start, end int64) []TimeSpan {
+	if len(grid) == 0 {
+		return nil
+	}
+	var gaps []TimeSpan
+	prevTS, prevStep := start, grid[0].step
+	report := func(from, to, step int64) {
+		if to-from > gapFactor*step {
+			gaps = append(gaps, TimeSpan{From: time.Unix(from, 0).UTC(), To: time.Unix(to, 0).UTC()})
+		}
+	}
+	for _, g := range grid {
+		if !has(g.ts) {
+			continue
+		}
+		report(prevTS, g.ts, max(prevStep, g.step))
+		prevTS, prevStep = g.ts, g.step
+	}
+	report(prevTS, end, prevStep)
+	return gaps
+}
+
+// nearestRank is the p-quantile (0 < p <= 1) of vals by the nearest-rank
+// method: the value at rank ceil(p*n) of the sorted list. It is exact, takes
+// an actual sample and needs no interpolation convention. NaN for no values.
+func nearestRank(vals []float64, p float64) float64 {
+	if len(vals) == 0 {
+		return math.NaN()
+	}
+	s := append([]float64(nil), vals...)
+	sort.Float64s(s)
+	rank := int(math.Ceil(p*float64(len(s)) - 1e-9)) // the epsilon keeps 0.95*20 from rounding up to 20
+	return s[min(max(rank, 1), len(s))-1]
+}

internal/api/graph_test.go

@@ -0,0 +1,444 @@
+package api_test
+
+import (
+	"encoding/json"
+	"errors"
+	"fmt"
+	"math"
+	"net/url"
+	"sort"
+	"strings"
+	"testing"
+	"time"
+
+	"github.com/v10networks/nmon/internal/api"
+	"github.com/v10networks/nmon/internal/store"
+	"github.com/v10networks/nmon/internal/vmsup"
+)
+
+// graphVM fakes the two stores. hot and long say whether a store has a sample
+// at ts; the value is a function of direction and time so tests can check which store answered.
+type graphVM struct {
+	hot, long func(ts int64) bool
+	hotVal    func(dir string, ts int64) float64
+	longVal   func(dir string, ts int64) float64
+	longErr   error
+}
+
+func dirOf(expr string) string {
+	if strings.Contains(expr, `dir="in"`) || strings.Contains(expr, "InOctets") {
+		return "in"
+	}
+	return "out"
+}
+
+func (g *graphVM) fn(storeName, expr string, from, to time.Time, step time.Duration) ([]byte, error) {
+	has, val := g.hot, g.hotVal
+	if storeName == "long" {
+		if g.longErr != nil {
+			return nil, g.longErr
+		}
+		has, val = g.long, g.longVal
+	}
+	dir := dirOf(expr)
+	vals := map[int64]float64{}
+	for ts := from.Unix(); ts <= to.Unix(); ts += int64(step / time.Second) {
+		if has == nil || has(ts) {
+			vals[ts] = val(dir, ts)
+		}
+	}
+	if len(vals) == 0 {
+		return emptyMatrix, nil
+	}
+	return matrix(mrow{labels: map[string]string{"dir": dir}, vals: vals}), nil
+}
+
+func rising(dir string, ts int64) float64 {
+	if dir == "in" {
+		return 1e6 + float64(ts%100000)
+	}
+	return 2e6 + float64(ts%100000)
+}
+
+func newGraphEnv(t *testing.T, vm *graphVM, mut ...func(*store.Interface)) (*env, store.Interface) {
+	e := newEnv(t, 0)
+	e.q.fn = vm.fn
+	d := e.device(t, "Core", "", "")
+	return e, e.iface(t, d, 1, "xe-0/0/1", "uplink", mut...)
+}
+
+func iso(ts time.Time) string { return ts.UTC().Format(time.RFC3339) }
+
+func graphURL(id string, from, to time.Time, extra string) string {
+	return "/api/v1/graph?iface=" + id + "&from=" + url.QueryEscape(iso(from)) + "&to=" + url.QueryEscape(iso(to)) + extra
+}
+
+func TestGraphRawTierWithinHotRetention(t *testing.T) {
+	vm := &graphVM{hotVal: rising}
+	e, i := newGraphEnv(t, vm)
+	var g api.GraphResponse
+	rec := e.getJSON(t, graphURL(i.ID, t0.Add(-time.Hour), t0, ""), &g)
+	assertNoLeaks(t, "graph", rec.Body.Bytes())
+	if g.Tier != "raw" || g.StepSeconds != 60 || g.StitchedAt != nil || len(g.Tiers) != 0 || g.Unreliable {
+		t.Fatalf("raw graph: %+v", g)
+	}
+	if g.Partial == nil || len(g.Partial) != 0 {
+		t.Errorf("partial must be [] when complete: %v", g.Partial)
+	}
+	if g.Iface.ID != i.ID || g.Iface.IfName != "xe-0/0/1" || g.Iface.IfAlias != "uplink" || g.Iface.SpeedBPS != 1_000_000_000 || g.Iface.Device.Name != "Core" {
+		t.Errorf("iface: %+v", g.Iface)
+	}
+	if len(g.Series.In) != 61 || len(g.Series.Out) != 61 || g.Series.InMax != nil {
+		t.Fatalf("series: %d in, %d out", len(g.Series.In), len(g.Series.Out))
+	}
+	first, last := g.Series.In[0], g.Series.In[60]
+	if first.TS != t0.Add(-time.Hour).Unix() || last.TS != t0.Unix() || first.V == nil || *first.V != rising("in", first.TS) {
+		t.Errorf("first %+v last %+v", first, last)
+	}
+	if *g.Series.Out[10].V != rising("out", g.Series.Out[10].TS) {
+		t.Errorf("out series %+v", g.Series.Out[10])
+	}
+	qs := e.q.queries()
+	if len(qs) != 2 || qs[0].store != "hot" || qs[0].step != time.Minute ||
+		qs[0].expr != `rate(ifHCInOctets{iface="`+i.ID+`"}[120s])*8` || !strings.Contains(qs[1].expr, "ifHCOutOctets") {
+		t.Errorf("queries: %+v", qs)
+	}
+	var raw map[string]json.RawMessage
+	_ = json.Unmarshal(rec.Body.Bytes(), &raw)
+	for _, k := range []string{"stitched_at", "tiers", "unreliable_reason", "p95"} {
+		if _, ok := raw[k]; ok {
+			t.Errorf("%s must be omitted from a plain raw graph", k)
+		}
+	}
+	if !strings.HasPrefix(string(raw["series"]), `{"in":[[`) {
+		t.Errorf("points must be [ts,value] pairs: %.60s", raw["series"])
+	}
+}
+
+func TestGraphUses32BitCountersWhenNoHC(t *testing.T) {
+	e, i := newGraphEnv(t, &graphVM{hotVal: rising}, func(i *store.Interface) { i.HasHCCounters = false })
+	var g api.GraphResponse
+	e.getJSON(t, graphURL(i.ID, t0.Add(-time.Hour), t0, ""), &g)
+	if q := e.q.queries()[0].expr; !strings.Contains(q, "ifInOctets{") || strings.Contains(q, "HC") {
+		t.Errorf("32-bit query: %s", q)
+	}
+}
+
+func TestGraphStepDefaultsAndLimits(t *testing.T) {
+	for _, tc := range []struct {
+		rng  time.Duration
+		step int64
+	}{{time.Hour, 60}, {24 * time.Hour, 120}, {7 * 24 * time.Hour, 660}, {30 * 24 * time.Hour, 2640}} {
+		e, i := newGraphEnv(t, &graphVM{hotVal: rising})
+		var g api.GraphResponse
+		e.getJSON(t, graphURL(i.ID, t0.Add(-tc.rng), t0, ""), &g)
+		if g.StepSeconds != tc.step || g.Tier != "raw" || g.StitchedAt != nil {
+			t.Errorf("range %s: step %d tier %s stitched %v, want step %d raw", tc.rng, g.StepSeconds, g.Tier, g.StitchedAt, tc.step)
+		}
+		if n := len(g.Series.In); n < 700 && tc.rng >= 24*time.Hour || n > 1001 {
+			t.Errorf("range %s: %d points", tc.rng, n)
+		}
+		for _, p := range g.Series.In {
+			if p.TS%g.StepSeconds != 0 {
+				t.Fatalf("range %s: sample %d is not aligned to the %d s step", tc.rng, p.TS, g.StepSeconds)
+			}
+		}
+	}
+	e, i := newGraphEnv(t, &graphVM{hotVal: rising})
+	var g api.GraphResponse
+	e.getJSON(t, graphURL(i.ID, t0.Add(-time.Hour), t0, "&step=300"), &g)
+	if g.StepSeconds != 300 || len(g.Series.In) != 13 {
+		t.Errorf("explicit step: %d, %d points", g.StepSeconds, len(g.Series.In))
+	}
+	isProblem(t, e.do("GET", graphURL(i.ID, t0.Add(-30*24*time.Hour), t0, "&step=1"), ""), 422)
+}
+
+func TestGraphStitchesHourlyLongDataToRawHot(t *testing.T) {
+	join := t0.Add(-30 * 24 * time.Hour)
+	vm := &graphVM{
+		hot: func(ts int64) bool { return ts >= join.Unix() }, hotVal: rising,
+		longVal: func(dir string, ts int64) float64 { return -1 }, // long values are recognisable
+	}
+	e, i := newGraphEnv(t, vm)
+	from := t0.Add(-40 * 24 * time.Hour)
+	var g api.GraphResponse
+	e.getJSON(t, graphURL(i.ID, from, t0, "&max=true"), &g)
+	if g.StitchedAt == nil || g.Tier != "raw" || len(g.Tiers) != 2 {
+		t.Fatalf("stitched graph: stitched_at=%v tier=%s tiers=%+v", g.StitchedAt, g.Tier, g.Tiers)
+	}
+	if g.Tiers[0].Tier != "1h" || g.Tiers[0].StepSeconds != 3600 || g.Tiers[1].Tier != "raw" || g.Tiers[1].StepSeconds != g.StepSeconds {
+		t.Errorf("tiers: %+v step=%d", g.Tiers, g.StepSeconds)
+	}
+	if !g.Tiers[0].To.Equal(*g.StitchedAt) || !g.Tiers[1].From.Equal(*g.StitchedAt) || g.StitchedAt.Before(join) ||
+		g.StitchedAt.Sub(join) >= time.Duration(g.StepSeconds)*time.Second {
+		t.Errorf("stitched_at %v should be the hot retention edge %v rounded up by less than a step", g.StitchedAt, join)
+	}
+	var long, rawN int
+	prev := int64(0)
+	for _, p := range g.Series.In {
+		if p.TS <= prev {
+			t.Fatalf("series not strictly increasing at %d", p.TS)
+		}
+		prev = p.TS
+		if p.V == nil {
+			t.Fatalf("hole at %d: both stores have data here", p.TS)
+		}
+		if *p.V == -1 {
+			long++
+			if p.TS >= g.StitchedAt.Unix() || p.TS%3600 != 0 {
+				t.Errorf("long sample %d misplaced", p.TS)
+			}
+		} else {
+			rawN++
+			if p.TS < g.StitchedAt.Unix() {
+				t.Errorf("raw sample %d before the join", p.TS)
+			}
+		}
+	}
+	if long < 200 || rawN < 400 {
+		t.Errorf("%d long and %d raw samples", long, rawN)
+	}
+	if len(g.Partial) != 0 {
+		t.Errorf("no gaps expected: %v", g.Partial)
+	}
+	if len(g.Series.InMax) != len(g.Series.In) || len(g.Series.OutMax) != len(g.Series.Out) {
+		t.Errorf("max series lengths %d/%d", len(g.Series.InMax), len(g.Series.OutMax))
+	}
+	var sawLong, sawHot bool
+	for _, c := range e.q.queries() {
+		switch c.store {
+		case "long":
+			sawLong = true
+			if !strings.Contains(c.expr, "max by (dir)") || !strings.Contains(c.expr, `iface="`+i.ID+`"`) ||
+				(!strings.Contains(c.expr, "nmon_if_rate_bps_avg_1h") && !strings.Contains(c.expr, "nmon_if_rate_bps_max_1h")) {
+				t.Errorf("long query: %s", c.expr)
+			}
+		case "hot":
+			sawHot = true
+			if c.from.Before(*g.StitchedAt) {
+				t.Errorf("hot queried before the join: %v", c.from)
+			}
+		}
+	}
+	if !sawLong || !sawHot {
+		t.Error("a stitched graph must query both stores")
+	}
+}
+
+func TestGraphLongRangeUsesCoarserStepAndHourlyAverages(t *testing.T) {
+	e, i := newGraphEnv(t, &graphVM{hotVal: rising, longVal: rising})
+	var g api.GraphResponse
+	e.getJSON(t, graphURL(i.ID, t0.Add(-365*24*time.Hour), t0, ""), &g)
+	if g.StitchedAt == nil || g.Tiers[0].StepSeconds%3600 != 0 || g.Tiers[0].StepSeconds <= 3600 {
+		t.Fatalf("1y tiers: %+v", g.Tiers)
+	}
+	var longExpr string
+	for _, c := range e.q.queries() {
+		if c.store == "long" {
+			longExpr = c.expr
+		}
+	}
+	if !strings.Contains(longExpr, "avg_over_time((max by (dir)") || !strings.Contains(longExpr, ":3600s])") {
+		t.Errorf("coarse long query should average the hourly points: %s", longExpr)
+	}
+}
+
+func TestGraphOlderThanHotIsLongTierOnly(t *testing.T) {
+	vm := &graphVM{hot: func(int64) bool { return false }, hotVal: rising, longVal: rising}
+	e, i := newGraphEnv(t, vm)
+	var g api.GraphResponse
+	e.getJSON(t, graphURL(i.ID, t0.Add(-90*24*time.Hour), t0.Add(-60*24*time.Hour), ""), &g)
+	if g.Tier != "1h" || g.StepSeconds != 3600 || g.StitchedAt != nil || len(g.Tiers) != 0 || len(g.Series.In) < 700 {
+		t.Errorf("long-only graph: tier=%s step=%d stitched=%v %d points", g.Tier, g.StepSeconds, g.StitchedAt, len(g.Series.In))
+	}
+	for _, c := range e.q.queries() {
+		if c.store != "long" {
+			t.Errorf("hot queried for a range wholly beyond hot retention: %+v", c)
+		}
+	}
+}
+
+func TestGraphReportsPartialWhereNeitherStoreHasData(t *testing.T) {
+	// Until M5's rollup exists the long store is empty: the stitched span is partial, honestly.
+	join := t0.Add(-30 * 24 * time.Hour)
+	vm := &graphVM{hot: func(ts int64) bool { return ts >= join.Unix() }, hotVal: rising, long: func(int64) bool { return false }}
+	e, i := newGraphEnv(t, vm)
+	from := t0.Add(-40 * 24 * time.Hour)
+	var g api.GraphResponse
+	e.getJSON(t, graphURL(i.ID, from, t0, ""), &g)
+	if g.StitchedAt == nil || len(g.Partial) != 1 {
+		t.Fatalf("partial: %+v stitched %v", g.Partial, g.StitchedAt)
+	}
+	p := g.Partial[0]
+	if p.From.After(from.Add(time.Hour)) || p.To.Before(join) || p.To.After(join.Add(2*time.Hour)) {
+		t.Errorf("gap %v..%v, want about %v..%v", p.From, p.To, from, join)
+	}
+	for _, pt := range g.Series.In {
+		if pt.TS < g.StitchedAt.Unix() && pt.V != nil {
+			t.Fatalf("a null expected before the join, got %v at %d", *pt.V, pt.TS)
+		}
+	}
+
+	// a short hole in raw data is a partial span; a single missed sample is not
+	e2, i2 := newGraphEnv(t, &graphVM{hotVal: rising, hot: func(ts int64) bool {
+		m := (ts - t0.Add(-time.Hour).Unix()) / 60
+		return m < 20 || m > 50 && m != 55
+	}})
+	e2.getJSON(t, graphURL(i2.ID, t0.Add(-time.Hour), t0, ""), &g)
+	if len(g.Partial) != 1 || !g.Partial[0].From.Equal(t0.Add(-41*time.Minute)) || !g.Partial[0].To.Equal(t0.Add(-9*time.Minute)) {
+		t.Errorf("hole: %+v", g.Partial)
+	}
+
+	// no data at all: one partial span covering the range
+	e3, i3 := newGraphEnv(t, &graphVM{hotVal: rising, hot: func(int64) bool { return false }})
+	e3.getJSON(t, graphURL(i3.ID, t0.Add(-time.Hour), t0, ""), &g)
+	if len(g.Partial) != 1 || !g.Partial[0].From.Equal(t0.Add(-time.Hour)) || !g.Partial[0].To.Equal(t0) {
+		t.Errorf("empty: %+v", g.Partial)
+	}
+	// data that starts late: a leading gap
+	e4, i4 := newGraphEnv(t, &graphVM{hotVal: rising, hot: func(ts int64) bool { return ts >= t0.Add(-20*time.Minute).Unix() }})
+	e4.getJSON(t, graphURL(i4.ID, t0.Add(-time.Hour), t0, ""), &g)
+	if len(g.Partial) != 1 || !g.Partial[0].From.Equal(t0.Add(-time.Hour)) || !g.Partial[0].To.Equal(t0.Add(-20*time.Minute)) {
+		t.Errorf("leading gap: %+v", g.Partial)
+	}
+}
+
+func TestGraphLongStoreDownIsPartialNotAnError(t *testing.T) {
+	join := t0.Add(-30 * 24 * time.Hour)
+	vm := &graphVM{hot: func(ts int64) bool { return ts >= join.Unix() }, hotVal: rising, longErr: fmt.Errorf("%w: long", vmsup.ErrStoreDown)}
+	e, i := newGraphEnv(t, vm)
+	var g api.GraphResponse
+	e.getJSON(t, graphURL(i.ID, t0.Add(-40*24*time.Hour), t0, ""), &g)
+	if g.StitchedAt == nil || len(g.Partial) != 1 {
+		t.Errorf("long store down: %+v", g.Partial)
+	}
+}
+
+func TestGraphUnreliableInterfaceHasNoSeries(t *testing.T) {
+	for name, tc := range map[string]struct {
+		mut    func(*store.Interface)
+		reason string
+	}{
+		"32-bit fast link":  {func(i *store.Interface) { i.Unreliable, i.HasHCCounters = true, false }, "counter_32bit_fast_link"},
+		"discontinuities":   {func(i *store.Interface) { i.Unreliable, i.CounterDiscontinuity = true, 3 }, "counter_discontinuity"},
+		"unreliable for HC": {func(i *store.Interface) { i.Unreliable = true }, "counter_unreliable"},
+	} {
+		t.Run(name, func(t *testing.T) {
+			e, i := newGraphEnv(t, &graphVM{hotVal: rising}, tc.mut)
+			var g api.GraphResponse
+			rec := e.getJSON(t, graphURL(i.ID, t0.Add(-time.Hour), t0, "&max=true&p95=true"), &g)
+			if !g.Unreliable || g.UnreliableReason != tc.reason || len(g.Series.In) != 0 || len(g.Series.Out) != 0 ||
+				g.P95 != nil || g.Partial == nil || g.Tier != "raw" || g.StepSeconds != 60 {
+				t.Errorf("unreliable graph: %+v", g)
+			}
+			if n := len(e.q.queries()); n != 0 {
+				t.Errorf("an unreliable interface must not be queried, %d queries", n)
+			}
+			if !strings.Contains(rec.Body.String(), `"in":[],"out":[]`) {
+				t.Errorf("series must be empty arrays: %s", rec.Body)
+			}
+		})
+	}
+}
+
+func TestGraphDirectionFilterAndMax(t *testing.T) {
+	e, i := newGraphEnv(t, &graphVM{hotVal: rising})
+	var g api.GraphResponse
+	e.getJSON(t, graphURL(i.ID, t0.Add(-time.Hour), t0, "&dir=out&max=true"), &g)
+	if len(g.Series.In) != 0 || len(g.Series.Out) != 61 || len(g.Series.OutMax) != 61 || g.Series.InMax != nil {
+		t.Errorf("dir=out: in=%d out=%d out_max=%d", len(g.Series.In), len(g.Series.Out), len(g.Series.OutMax))
+	}
+	qs := e.q.queries()
+	if len(qs) != 2 {
+		t.Fatalf("queries %d", len(qs))
+	}
+	for _, c := range qs {
+		if strings.Contains(c.expr, "In") {
+			t.Errorf("dir=out queried the in counter: %s", c.expr)
+		}
+	}
+	if !strings.Contains(qs[1].expr, "max_over_time((rate(ifHCOutOctets{iface=") || !strings.Contains(qs[1].expr, "[60s:60s])") {
+		t.Errorf("max query: %s", qs[1].expr)
+	}
+	isProblem(t, e.do("GET", graphURL(i.ID, t0.Add(-time.Hour), t0, "&dir=sideways"), ""), 422)
+}
+
+// referenceP95 is an independent nearest-rank implementation: the smallest
+// value such that at least 95% of the values are at or below it.
+func referenceP95(vals []float64) float64 {
+	s := append([]float64(nil), vals...)
+	sort.Float64s(s)
+	for _, v := range s {
+		n := 0
+		for _, x := range s {
+			if x <= v {
+				n++
+			}
+		}
+		if float64(n)*100 >= 95*float64(len(s)) {
+			return v
+		}
+	}
+	return math.NaN()
+}
+
+func TestGraphP95IsNearestRankOverFiveMinuteAverages(t *testing.T) {
+	// 24 h of 5-minute averages; one hour of the day has no data.
+	from := t0.Add(-24 * time.Hour)
+	vals := func(dir string, ts int64) float64 {
+		k := float64((ts / 300 * 7919) % 1000) // scrambled but deterministic
+		if dir == "out" {
+			k *= 3
+		}
+		return k * 1000
+	}
+	hole := func(ts int64) bool { return ts < t0.Add(-5*time.Hour).Unix() || ts >= t0.Add(-4*time.Hour).Unix() }
+	e, i := newGraphEnv(t, &graphVM{hotVal: vals, hot: hole})
+	var g api.GraphResponse
+	e.getJSON(t, graphURL(i.ID, from, t0, "&p95=true"), &g)
+	if g.P95 == nil || g.P95.Source != "live" || g.P95.InBPS == nil || g.P95.OutBPS == nil {
+		t.Fatalf("p95: %+v", g.P95)
+	}
+	var in, out []float64
+	for ts := from.Unix(); ts <= t0.Unix(); ts += 300 {
+		if hole(ts) {
+			in, out = append(in, vals("in", ts)), append(out, vals("out", ts))
+		}
+	}
+	if *g.P95.InBPS != referenceP95(in) || *g.P95.OutBPS != referenceP95(out) {
+		t.Errorf("p95 in %v out %v, reference %v / %v", *g.P95.InBPS, *g.P95.OutBPS, referenceP95(in), referenceP95(out))
+	}
+	wantCov := float64(len(in)) / (24 * 12)
+	if math.Abs(g.P95.Coverage-wantCov) > 0.01 || g.P95.Coverage >= 1 {
+		t.Errorf("coverage %v, want about %v", g.P95.Coverage, wantCov)
+	}
+	var withoutP95 api.GraphResponse
+	e.getJSON(t, graphURL(i.ID, from, t0, ""), &withoutP95)
+	if withoutP95.P95 != nil {
+		t.Error("p95 only when asked")
+	}
+}
+
+func TestGraphErrors(t *testing.T) {
+	e, i := newGraphEnv(t, &graphVM{hotVal: rising})
+	isProblem(t, e.do("GET", "/api/v1/graph", ""), 422)
+	isProblem(t, e.do("GET", "/api/v1/graph?iface=01ARZ3NDEKTSV4RRFFQ69G5FAV", ""), 404)
+	isProblem(t, e.do("GET", graphURL(i.ID, t0, t0.Add(-time.Hour), ""), ""), 422)
+	isProblem(t, e.do("GET", "/api/v1/graph?iface="+i.ID+"&from=yesterday", ""), 422)
+	isProblem(t, e.do("GET", "/api/v1/graph?iface="+i.ID+"&step=0", ""), 422)
+	e.q.fn = func(string, string, time.Time, time.Time, time.Duration) ([]byte, error) {
+		return nil, fmt.Errorf("%w: hot", vmsup.ErrStoreDown)
+	}
+	isProblem(t, e.do("GET", graphURL(i.ID, t0.Add(-time.Hour), t0, ""), ""), 503)
+	e.q.fn = func(string, string, time.Time, time.Time, time.Duration) ([]byte, error) {
+		return nil, errors.New("boom")
+	}
+	isProblem(t, e.do("GET", graphURL(i.ID, t0.Add(-time.Hour), t0, ""), ""), 502)
+	// defaults: to=now, from=1h earlier
+	e.q.fn = (&graphVM{hotVal: rising}).fn
+	var g api.GraphResponse
+	e.getJSON(t, "/api/v1/graph?iface="+i.ID, &g)
+	if len(g.Series.In) != 61 || g.Series.In[60].TS != t0.Unix() {
+		t.Errorf("default range: %d points", len(g.Series.In))
+	}
+}

internal/api/graph_types.go

@@ -0,0 +1,125 @@
+package api
+
+import (
+	"encoding/json"
+	"time"
+
+	"github.com/danielgtaylor/huma/v2"
+)
+
+// Graph tiers: raw samples from the hot store, or hourly rollups from the long store.
+const (
+	tierRaw = "raw"
+	tier1h  = "1h"
+)
+
+// Point is one sample of a series: Unix seconds and bits per second, or null
+// when the store had no data for that step. It marshals as [ts, value].
+type Point struct {
+	TS int64
+	V  *float64
+}
+
+// MarshalJSON writes the compact [unix_s, bps|null] form uPlot can use as is.
+func (p Point) MarshalJSON() ([]byte, error) {
+	return json.Marshal([]any{p.TS, p.V})
+}
+
+// UnmarshalJSON reads the [ts, value] form (tests and clients written in Go).
+func (p *Point) UnmarshalJSON(b []byte) error {
+	var raw [2]json.RawMessage
+	if err := json.Unmarshal(b, &raw); err != nil {
+		return err
+	}
+	if err := json.Unmarshal(raw[0], &p.TS); err != nil {
+		return err
+	}
+	return json.Unmarshal(raw[1], &p.V)
+}
+
+// Schema describes Point as a two-element tuple. huma's Schema has no
+// prefixItems field, so it goes in as an extension; generated clients type it as [number, number | null].
+func (Point) Schema(r huma.Registry) *huma.Schema {
+	two := 2
+	r.Map()["Point"] = &huma.Schema{
+		Type: huma.TypeArray, MinItems: &two, MaxItems: &two,
+		Description: "[unix seconds, bits per second or null].",
+		Extensions: map[string]any{"prefixItems": []any{
+			map[string]any{"type": "number", "description": "unix seconds"},
+			map[string]any{"anyOf": []any{
+				map[string]any{"type": "number", "description": "bits per second"}, map[string]any{"type": "null"},
+			}},
+		}},
+	}
+	return &huma.Schema{Ref: "#/components/schemas/Point"}
+}
+
+// GraphIface identifies the graphed interface.
+type GraphIface struct {
+	ID       string    `json:"id"`
+	IfName   string    `json:"ifname"`
+	IfAlias  string    `json:"ifalias"`
+	SpeedBPS int64     `json:"speed_bps"`
+	Device   DeviceRef `json:"device"`
+}
+
+// TimeSpan is a half-open stretch of time.
+type TimeSpan struct {
+	From time.Time `json:"from"`
+	To   time.Time `json:"to"`
+}
+
+// GraphTier says which store and step answered one stretch of a stitched graph.
+type GraphTier struct {
+	From        time.Time `json:"from"`
+	To          time.Time `json:"to"`
+	Tier        string    `json:"tier" enum:"raw,1h"`
+	StepSeconds int64     `json:"step_seconds"`
+}
+
+// GraphSeries holds the bits-per-second series. in and out are always present
+// (empty for a direction not asked for); the max series only when requested.
+type GraphSeries struct {
+	In     []Point `json:"in"`
+	Out    []Point `json:"out"`
+	InMax  []Point `json:"in_max,omitempty"`
+	OutMax []Point `json:"out_max,omitempty"`
+}
+
+// set stores pts as the average (or maximum) series of dir.
+func (g *GraphSeries) set(dir string, isMax bool, pts []Point) {
+	switch {
+	case dir == dirIn && isMax:
+		g.InMax = pts
+	case dir == dirIn:
+		g.In = pts
+	case isMax:
+		g.OutMax = pts
+	default:
+		g.Out = pts
+	}
+}
+
+// GraphP95 is the 95th percentile of 5-minute averages (nearest rank).
+type GraphP95 struct {
+	InBPS    *float64 `json:"in_bps" nullable:"true"`
+	OutBPS   *float64 `json:"out_bps" nullable:"true"`
+	Source   string   `json:"source" enum:"materialised,live"`
+	Coverage float64  `json:"coverage" doc:"Share of the drawn range's 5-minute slots that had data, 0 to 1."`
+}
+
+// GraphResponse is a rate graph for one interface. A graph answered from two
+// stores always carries stitched_at; stretches with no data in either store are
+// listed in partial; an unreliable interface has no series at all.
+type GraphResponse struct {
+	Iface            GraphIface  `json:"iface"`
+	StepSeconds      int64       `json:"step_seconds" doc:"Step of the newest tier."`
+	Tier             string      `json:"tier" enum:"raw,1h" doc:"Tier of the newest data."`
+	StitchedAt       *time.Time  `json:"stitched_at,omitempty" doc:"Where the hourly long-store data ends and raw hot data begins."`
+	Tiers            []GraphTier `json:"tiers,omitempty" doc:"Present when two stores answered."`
+	UnreliableReason string      `json:"unreliable_reason,omitempty" doc:"Why the counters are not trusted, e.g. counter_32bit_fast_link."`
+	Partial          []TimeSpan  `json:"partial" doc:"Stretches of the range where neither store has data."`
+	Unreliable       bool        `json:"unreliable"`
+	Series           GraphSeries `json:"series"`
+	P95              *GraphP95   `json:"p95,omitempty"`
+}

internal/api/health.go

@@ -0,0 +1,184 @@
+package api
+
+import (
+	"context"
+	"net/http"
+	"sync"
+	"time"
+
+	"github.com/danielgtaylor/huma/v2"
+
+	"github.com/v10networks/nmon/internal/metrics"
+	"github.com/v10networks/nmon/internal/store"
+)
+
+// PollerDeviceHealth is the poller's view of one device. It uses the slug, never the numeric ID.
+type PollerDeviceHealth struct {
+	Slug                string     `json:"slug"`
+	Name                string     `json:"name"`
+	State               string     `json:"state" enum:"ok,degraded,backoff" doc:"backoff: healthy but polled slower than its base interval."`
+	Varbinds            int64      `json:"varbinds" doc:"Varbinds per request right now."`
+	IntervalS           int64      `json:"interval_s" doc:"Current cadence, backoff included."`
+	BaseIntervalS       int64      `json:"base_interval_s"`
+	LastCycleS          float64    `json:"last_cycle_s" doc:"Duration of the last cycle."`
+	MissedDeadlines     int64      `json:"missed_deadlines" doc:"Consecutive cycles that ended at the deadline."`
+	ConsecutiveFailures int64      `json:"consecutive_failures"`
+	LastError           string     `json:"last_error"`
+	NextCycle           *time.Time `json:"next_cycle" nullable:"true"`
+	Profile             string     `json:"profile"`
+}
+
+// PollerTotals are the poller's aggregate numbers. The per-minute figures are
+// deltas of nmon's own counters over about the last minute.
+type PollerTotals struct {
+	PDUsPerMin           float64 `json:"pdus_per_min"`
+	TimeoutsPerMin       float64 `json:"timeouts_per_min"`
+	DeadlineMissesPerMin float64 `json:"deadline_misses_per_min"`
+	WriteQueueDepth      int64   `json:"write_queue_depth" doc:"Samples waiting in the hot write queue."`
+	WriteQueueCapacity   int64   `json:"write_queue_capacity"`
+	DevicesDegraded      int64   `json:"devices_degraded"`
+}
+
+// PollerHealth is the poller health page.
+type PollerHealth struct {
+	Devices []PollerDeviceHealth `json:"devices"`
+	Totals  PollerTotals         `json:"totals"`
+}
+
+func (s *server) registerHealth(api huma.API) {
+	huma.Register(api, huma.Operation{
+		OperationID: "get-poller-health", Method: http.MethodGet, Path: "/api/v1/poller/health", Tags: []string{"poller"},
+		Summary:     "Poller state of every polled device, with PDU, timeout and queue totals",
+		Description: "Rates are over about the last minute; the first call after start may report zero.",
+	}, s.pollerHealth)
+}
+
+func (s *server) pollerHealth(ctx context.Context, _ *struct{}) (*struct{ Body PollerHealth }, error) {
+	names, err := s.deviceNames(ctx)
+	if err != nil {
+		return nil, s.storeErr(err)
+	}
+	out := PollerHealth{Devices: []PollerDeviceHealth{}}
+	if s.PollerStatus != nil {
+		for _, d := range s.PollerStatus() {
+			h := PollerDeviceHealth{
+				Slug: d.Device, Name: names[d.Device], State: d.State, Varbinds: int64(d.Varbinds),
+				IntervalS: int64(d.Interval.Seconds()), BaseIntervalS: int64(d.BaseInterval.Seconds()),
+				LastCycleS: d.LastCycleDuration.Seconds(), MissedDeadlines: int64(d.MissedDeadlines),
+				ConsecutiveFailures: int64(d.ConsecutiveFailures), LastError: d.LastError, NextCycle: tp(d.NextCycle),
+				Profile: d.Profile,
+			}
+			if h.State == store.PollOK && d.Interval > d.BaseInterval {
+				h.State = store.PollBackoff
+			}
+			if h.State != store.PollOK {
+				out.Totals.DevicesDegraded++
+			}
+			out.Devices = append(out.Devices, h)
+		}
+	}
+	s.fillTotals(&out.Totals)
+	return &struct{ Body PollerHealth }{out}, nil
+}
+
+// deviceNames maps slugs to display names.
+func (s *server) deviceNames(ctx context.Context) (map[string]string, error) {
+	names := map[string]string{}
+	for off := int64(0); ; off += store.MaxLimit {
+		rows, n, err := s.Store.ListDevices(ctx, store.DeviceFilter{IncludeRetired: true}, store.Page{Offset: off, Limit: store.MaxLimit})
+		if err != nil {
+			return nil, err
+		}
+		for _, d := range rows {
+			names[d.Slug] = d.Name
+		}
+		if off+store.MaxLimit >= n {
+			return names, nil
+		}
+	}
+}
+
+// fillTotals reads nmon's own counters from the registry.
+func (s *server) fillTotals(t *PollerTotals) {
+	t.PDUsPerMin, t.TimeoutsPerMin, t.DeadlineMissesPerMin = s.rate.perMinute(s.readCounters())
+	for _, x := range s.Registry.Snapshot(s.Clock.Now()) {
+		if x.Name == "nmon_write_queue_depth" && labelValue(x.Labels, "queue") == "hot" {
+			t.WriteQueueDepth += int64(x.Value)
+		}
+	}
+	t.WriteQueueCapacity = int64(s.WriteQueueCapacity)
+}
+
+// counterSample is the registry's counter totals at one instant.
+type counterSample struct {
+	at                     time.Time
+	pdus, timeouts, misses float64
+}
+
+// readCounters sums the poll-path counters across all their series.
+func (s *server) readCounters() counterSample {
+	c := counterSample{at: s.Clock.Now()}
+	for _, x := range s.Registry.Snapshot(c.at) {
+		switch x.Name {
+		case "nmon_pdus_total":
+			if labelValue(x.Labels, "path") == "poll" {
+				c.pdus += x.Value
+			}
+		case "nmon_snmp_timeouts_total":
+			if labelValue(x.Labels, "path") == "poll" {
+				c.timeouts += x.Value
+			}
+		case "nmon_poll_deadline_missed_total":
+			c.misses += x.Value
+		}
+	}
+	return c
+}
+
+// counterRates turns successive counter totals into per-minute rates. It keeps
+// about a minute and a half of history and measures from the oldest sample, so
+// concurrent pollers of the page do not shrink the window.
+type counterRates struct {
+	mu      sync.Mutex
+	samples []counterSample
+}
+
+const rateHistory = 90 * time.Second
+
+// perMinute records cur and returns the per-minute rates since the oldest retained sample.
+func (c *counterRates) perMinute(cur counterSample) (pdus, timeouts, misses float64) {
+	c.mu.Lock()
+	defer c.mu.Unlock()
+	for len(c.samples) > 0 && cur.at.Sub(c.samples[0].at) > rateHistory {
+		c.samples = c.samples[1:]
+	}
+	defer func() { c.samples = append(c.samples, cur) }()
+	if len(c.samples) == 0 {
+		return 0, 0, 0
+	}
+	base := c.samples[0]
+	span := cur.at.Sub(base.at).Minutes()
+	if span <= 0 {
+		return 0, 0, 0
+	}
+	per := func(now, then float64) float64 { return max(now-then, 0) / span }
+	return per(cur.pdus, base.pdus), per(cur.timeouts, base.timeouts), per(cur.misses, base.misses)
+}
+
+func labelValue(ls []metrics.Label, name string) string {
+	for _, l := range ls {
+		if l.Name == name {
+			return l.Value
+		}
+	}
+	return ""
+}
+
+// tp is t in UTC, or nil for the zero time.
+func tp(t time.Time) *time.Time {
+	if t.IsZero() {
+		return nil
+	}
+	u := t.UTC()
+	return &u
+}

internal/api/helpers_test.go

@@ -0,0 +1,180 @@
+package api_test
+
+import (
+	"bytes"
+	"context"
+	"encoding/json"
+	"fmt"
+	"net/http/httptest"
+	"strings"
+	"testing"
+	"time"
+
+	"github.com/v10networks/nmon/internal/store"
+	"github.com/v10networks/nmon/internal/ulid"
+)
+
+// device stores a network device and returns it with its generated slug.
+func (e *env) device(t *testing.T, name, site, role string, mut ...func(*store.Device)) *store.Device {
+	t.Helper()
+	d := &store.Device{Name: name, Kind: store.KindNetwork, Site: site, Role: role, Enabled: true, Profile: "generic", MgmtIP: "192.0.2.1"}
+	for _, m := range mut {
+		m(d)
+	}
+	if err := e.st.CreateDevice(context.Background(), d); err != nil {
+		t.Fatal(err)
+	}
+	return d
+}
+
+// iface stores one interface of d and returns it.
+func (e *env) iface(t *testing.T, d *store.Device, idx int64, name, alias string, mut ...func(*store.Interface)) store.Interface {
+	t.Helper()
+	i := store.Interface{
+		ID: ulid.New(e.clk.Now()), DeviceID: d.ID, IfIndex: idx, IfName: name, IfDescr: name, IfAlias: alias,
+		IfSpeed: 1_000_000_000, IfHighSpeed: 1000, AdminStatus: 1, OperStatus: 1, HasHCCounters: true,
+		FirstSeen: e.clk.Now(), LastDiscovered: e.clk.Now(),
+	}
+	for _, m := range mut {
+		m(&i)
+	}
+	if err := e.st.UpsertInterfaces(context.Background(), d.ID, []store.Interface{i}); err != nil {
+		t.Fatal(err)
+	}
+	return i
+}
+
+// getJSON GETs path and decodes a 200 body into v.
+func (e *env) getJSON(t *testing.T, path string, v any) *httptest.ResponseRecorder {
+	t.Helper()
+	rec := e.do("GET", path, "")
+	if rec.Code != 200 {
+		t.Fatalf("GET %s: %d %s", path, rec.Code, rec.Body)
+	}
+	if err := json.Unmarshal(rec.Body.Bytes(), v); err != nil {
+		t.Fatalf("GET %s: %v: %s", path, err, rec.Body)
+	}
+	return rec
+}
+
+// vector builds an instant-query response from rows of (labels, value).
+type vrow struct {
+	labels map[string]string
+	v      float64
+}
+
+func vector(rows ...vrow) []byte {
+	var b bytes.Buffer
+	b.WriteString(`{"status":"success","data":{"resultType":"vector","result":[`)
+	for i, r := range rows {
+		if i > 0 {
+			b.WriteByte(',')
+		}
+		lb, _ := json.Marshal(r.labels)
+		fmt.Fprintf(&b, `{"metric":%s,"value":[1,"%v"]}`, lb, r.v)
+	}
+	b.WriteString(`]}}`)
+	return b.Bytes()
+}
+
+// matrix builds a range-query response with one series per entry of rows:
+// labels and a map of unix second to value.
+type mrow struct {
+	labels map[string]string
+	vals   map[int64]float64
+}
+
+func matrix(rows ...mrow) []byte {
+	var b bytes.Buffer
+	b.WriteString(`{"status":"success","data":{"resultType":"matrix","result":[`)
+	for i, r := range rows {
+		if i > 0 {
+			b.WriteByte(',')
+		}
+		lb, _ := json.Marshal(r.labels)
+		fmt.Fprintf(&b, `{"metric":%s,"values":[`, lb)
+		first := true
+		for _, ts := range sortedKeys(r.vals) {
+			if !first {
+				b.WriteByte(',')
+			}
+			first = false
+			fmt.Fprintf(&b, `[%d,"%v"]`, ts, r.vals[ts])
+		}
+		b.WriteString(`]}`)
+	}
+	b.WriteString(`]}}`)
+	return b.Bytes()
+}
+
+func sortedKeys(m map[int64]float64) []int64 {
+	out := make([]int64, 0, len(m))
+	for k := range m {
+		out = append(out, k)
+	}
+	for i := 1; i < len(out); i++ {
+		for j := i; j > 0 && out[j] < out[j-1]; j-- {
+			out[j], out[j-1] = out[j-1], out[j]
+		}
+	}
+	return out
+}
+
+// emptyMatrix is a range response with no series.
+var emptyMatrix = []byte(`{"status":"success","data":{"resultType":"matrix","result":[]}}`)
+
+// walkJSON calls fn for every key/value of every object in the JSON document.
+func walkJSON(t *testing.T, body []byte, fn func(path, key string, val any)) {
+	t.Helper()
+	var doc any
+	if err := json.Unmarshal(body, &doc); err != nil {
+		t.Fatalf("not JSON: %v: %s", err, body)
+	}
+	var rec func(path string, v any)
+	rec = func(path string, v any) {
+		switch x := v.(type) {
+		case map[string]any:
+			for k, c := range x {
+				fn(path, k, c)
+				rec(path+"."+k, c)
+			}
+		case []any:
+			for i, c := range x {
+				rec(fmt.Sprintf("%s[%d]", path, i), c)
+			}
+		}
+	}
+	rec("$", doc)
+}
+
+// assertNoLeaks fails when body has a numeric id, a credential field or a secret.
+func assertNoLeaks(t *testing.T, what string, body []byte, secrets ...string) {
+	t.Helper()
+	walkJSON(t, body, func(path, key string, val any) {
+		lower := strings.ToLower(key)
+		if _, isNum := val.(float64); isNum && (lower == "id" || strings.HasSuffix(lower, "_id") || lower == "device_id") {
+			t.Errorf("%s: numeric id at %s.%s = %v", what, path, key, val)
+		}
+		for _, bad := range []string{"community", "password", "pass", "hash", "secret", "token", "credential"} {
+			if strings.Contains(lower, bad) {
+				t.Errorf("%s: credential-like key %s.%s", what, path, key)
+			}
+		}
+	})
+	for _, s := range secrets {
+		if bytes.Contains(body, []byte(s)) {
+			t.Errorf("%s: response contains secret %q", what, s)
+		}
+	}
+}
+
+var t0 = time.Date(2026, 10, 22, 12, 0, 0, 0, time.UTC)
+
+// doFrom is do with a chosen remote address, which the admission limits key on.
+func (e *env) doFrom(method, path, remote string) *httptest.ResponseRecorder {
+	req := httptest.NewRequest(method, path, nil)
+	req.RemoteAddr = remote
+	rec := httptest.NewRecorder()
+	e.h.ServeHTTP(rec, req)
+	return rec
+}

internal/api/integration_test.go

@@ -0,0 +1,208 @@
+//go:build integration && linux
+
+package api_test
+
+import (
+	"context"
+	"encoding/json"
+	"net/http"
+	"net/http/httptest"
+	"net/url"
+	"os"
+	"path/filepath"
+	"runtime"
+	"testing"
+	"time"
+
+	"github.com/v10networks/nmon/internal/api"
+	"github.com/v10networks/nmon/internal/clock"
+	"github.com/v10networks/nmon/internal/metrics"
+	"github.com/v10networks/nmon/internal/store"
+	"github.com/v10networks/nmon/internal/testutil"
+	"github.com/v10networks/nmon/internal/ulid"
+	"github.com/v10networks/nmon/internal/vmsup"
+)
+
+// TestIntegrationGraphFromRealStores writes synthetic octet counters whose rate
+// rises, and hourly rollups for the weeks before, into real hot and long
+// stores, then asks the API for a one-hour graph and a stitched 40-day graph.
+func TestIntegrationGraphFromRealStores(t *testing.T) {
+	bin, err := filepath.Abs(filepath.Join("..", "vmsup", "bin", "victoria-metrics-prod-linux-"+runtime.GOARCH))
+	if err != nil {
+		t.Fatal(err)
+	}
+	if _, err := os.Stat(bin); err != nil {
+		t.Skipf("store binary not found (%v); run scripts/fetch-vm.sh", err)
+	}
+	t.Setenv("NMON_VM_BINARY", bin)
+	t.Setenv("NMON_VM_BINARY_UNVERIFIED", "")
+	sup, err := vmsup.New(vmsup.Options{DataDir: t.TempDir()})
+	if err != nil {
+		t.Fatal(err)
+	}
+	ctx, cancel := context.WithTimeout(context.Background(), 3*time.Minute)
+	defer cancel()
+	if err := sup.Start(ctx); err != nil {
+		t.Fatal(err)
+	}
+	t.Cleanup(func() { _ = sup.Stop(context.Background()) })
+
+	clk := clock.Real()
+	st := testutil.OpenStore(t, clk)
+	dev := &store.Device{Name: "Core", Kind: store.KindNetwork, Enabled: true, Profile: "generic"}
+	if err := st.CreateDevice(ctx, dev); err != nil {
+		t.Fatal(err)
+	}
+	ifc := store.Interface{ID: ulid.New(clk.Now()), DeviceID: dev.ID, IfIndex: 1, IfName: "xe-0/0/1", IfSpeed: 1e9, IfHighSpeed: 1000,
+		AdminStatus: 1, OperStatus: 1, HasHCCounters: true}
+	if err := st.UpsertInterfaces(ctx, dev.ID, []store.Interface{ifc}); err != nil {
+		t.Fatal(err)
+	}
+
+	// 3 h of one-minute samples ending 2 min ago. The in rate climbs from 1 to 4 Mbit/s; out is a flat 500 kbit/s.
+	end := time.Now().Add(-2 * time.Minute).Truncate(time.Minute)
+	const minutes = 3 * 60
+	var hot []metrics.Sample
+	var in, out float64
+	for i := 0; i <= minutes; i++ {
+		ts := end.Add(-time.Duration(minutes-i) * time.Minute)
+		inBps := 1e6 + 3e6*float64(i)/minutes
+		in += inBps / 8 * 60
+		out += 500e3 / 8 * 60
+		hot = append(hot,
+			metrics.New("ifHCInOctets", in, ts, "device", dev.Slug, "iface", ifc.ID),
+			metrics.New("ifHCOutOctets", out, ts, "device", dev.Slug, "iface", ifc.ID))
+	}
+	// Hourly rollups for 40 days back to 31 days ago, 800 kbit/s in and 200 out.
+	var long []metrics.Sample
+	for h := 40 * 24; h >= 31*24; h-- {
+		ts := time.Now().Add(-time.Duration(h) * time.Hour).Truncate(time.Hour)
+		long = append(long,
+			metrics.New("nmon_if_rate_bps_avg_1h", 800e3, ts, "device", dev.Slug, "iface", ifc.ID, "dir", "in", "v", "1"),
+			metrics.New("nmon_if_rate_bps_avg_1h", 200e3, ts, "device", dev.Slug, "iface", ifc.ID, "dir", "out", "v", "1"))
+	}
+	for name, ss := range map[string][]metrics.Sample{vmsup.StoreHot: hot, vmsup.StoreLong: long} {
+		q := vmsup.NewQueue(name, sup, vmsup.QueueOptions{MaxAge: 100 * 24 * time.Hour})
+		if err := q.Write(ctx, ss); err != nil {
+			t.Fatal(err)
+		}
+		if err := q.Flush(ctx); err != nil {
+			t.Fatal(err)
+		}
+	}
+
+	h := api.New(api.Deps{Store: st, Querier: vmsup.NewQuerier(sup), Poller: noRefresh{}, Clock: clk})
+	get := func(q url.Values) api.GraphResponse {
+		rec := httptest.NewRecorder()
+		h.ServeHTTP(rec, httptest.NewRequest(http.MethodGet, "/api/v1/graph?"+q.Encode(), nil))
+		if rec.Code != http.StatusOK {
+			t.Fatalf("graph: %d %s", rec.Code, rec.Body)
+		}
+		var g api.GraphResponse
+		if err := json.Unmarshal(rec.Body.Bytes(), &g); err != nil {
+			t.Fatal(err)
+		}
+		return g
+	}
+	// The store needs a moment to make flushed samples searchable.
+	var g api.GraphResponse
+	deadline := time.Now().Add(30 * time.Second)
+	for {
+		now := time.Now()
+		g = get(url.Values{"iface": {ifc.ID}, "from": {now.Add(-time.Hour).UTC().Format(time.RFC3339)}, "to": {now.UTC().Format(time.RFC3339)},
+			"max": {"true"}, "p95": {"true"}})
+		if countValues(g.Series.In) > 30 || time.Now().After(deadline) {
+			break
+		}
+		time.Sleep(500 * time.Millisecond)
+	}
+	if g.Tier != "raw" || g.StitchedAt != nil || g.StepSeconds != 60 {
+		t.Fatalf("1h graph: tier=%s step=%d stitched=%v", g.Tier, g.StepSeconds, g.StitchedAt)
+	}
+	first, last := firstLast(g.Series.In)
+	if first == nil || last == nil || *last <= *first*1.1 || *first < 2.5e6 || *last > 4.2e6 {
+		t.Errorf("in series should rise from about 2.5 to 4 Mbit/s: first %v last %v", deref(first), deref(last))
+	}
+	if f, l := firstLast(g.Series.Out); f == nil || *f < 450e3 || *f > 550e3 || *l < 450e3 || *l > 550e3 {
+		t.Errorf("out series should be a flat 500 kbit/s: %v %v", deref(f), deref(l))
+	}
+	if countValues(g.Series.InMax) < 30 {
+		t.Errorf("max series: %d values", countValues(g.Series.InMax))
+	}
+	if g.P95 == nil || g.P95.InBPS == nil || *g.P95.InBPS < 2.5e6 || g.P95.Source != "live" || g.P95.Coverage <= 0 {
+		t.Errorf("p95: %+v", g.P95)
+	}
+
+	now := time.Now()
+	g = get(url.Values{"iface": {ifc.ID}, "from": {now.Add(-40 * 24 * time.Hour).UTC().Format(time.RFC3339)}, "to": {now.UTC().Format(time.RFC3339)}})
+	if g.StitchedAt == nil || len(g.Tiers) != 2 || g.Tiers[0].Tier != "1h" {
+		t.Fatalf("40d graph should be stitched: %+v", g.Tiers)
+	}
+	var fromLong int
+	for _, p := range g.Series.In {
+		if p.TS < g.StitchedAt.Unix() && p.V != nil {
+			fromLong++
+			if *p.V != 800e3 {
+				t.Fatalf("long sample %d = %v, want 800000", p.TS, *p.V)
+			}
+		}
+	}
+	if fromLong < 150 {
+		t.Errorf("only %d hourly samples came from the long store", fromLong)
+	}
+	if len(g.Partial) == 0 {
+		t.Error("hot has 3 h of data in a 30-day window: the rest is partial")
+	}
+
+	// A year needs a coarser step: the store must accept the averaging subquery and average equal hours to the same value.
+	g = get(url.Values{"iface": {ifc.ID}, "from": {now.Add(-365 * 24 * time.Hour).UTC().Format(time.RFC3339)}, "to": {now.UTC().Format(time.RFC3339)}})
+	if g.StitchedAt == nil || g.Tiers[0].StepSeconds <= 3600 {
+		t.Fatalf("1y tiers: %+v", g.Tiers)
+	}
+	var coarse int
+	for _, p := range g.Series.In {
+		if p.TS < g.StitchedAt.Unix() && p.V != nil {
+			coarse++
+			if *p.V < 799e3 || *p.V > 801e3 {
+				t.Errorf("coarse long sample %d = %v, want 800000", p.TS, *p.V)
+			}
+		}
+	}
+	if coarse == 0 {
+		t.Error("the 1y graph has no long-store samples")
+	}
+}
+
+type noRefresh struct{}
+
+func (noRefresh) Refresh() {}
+
+func countValues(ps []api.Point) int {
+	n := 0
+	for _, p := range ps {
+		if p.V != nil {
+			n++
+		}
+	}
+	return n
+}
+
+func firstLast(ps []api.Point) (first, last *float64) {
+	for _, p := range ps {
+		if p.V == nil {
+			continue
+		}
+		if first == nil {
+			first = p.V
+		}
+		last = p.V
+	}
+	return first, last
+}
+
+func deref(p *float64) float64 {
+	if p == nil {
+		return -1
+	}
+	return *p
+}