feat(api): serve felis_* metrics on the internal face (build-failure counter's only scrape path) (94f71eea) · Commits · FelisMC / Felis · GitLab

docs/openapi.yaml

+20 −0

Changes for docs/openapi.yaml: 20 added lines, 0 removed lines.
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		@@ -467,6 +467,26 @@ paths:
		'503':
		$ref: '#/components/responses/ServiceUnavailable'

		/metrics:
		get:
		tags: [metrics]
		operationId: metrics
		summary: Prometheus metrics (felis_* collectors) on the internal face.
		description: >-
		Scrape-only infrastructure route, not a product API: the internal listener is
		ClusterIP-only and a Prometheus scrape carries no token, the same stance as the
		probes. Serves the felis_* exposition documented in troubleshooting §14; the
		external face never serves it.
		x-felis-face: [internal]
		x-felis-tier: public
		security: []
		responses:
		'200':
		description: Prometheus text exposition format.
		content:
		text/plain:
		schema: { type: string }

		/session/minecraft/hasJoined:
		get:
		tags: [nano]

+5 −1

Changes for internal/api/api.go: 5 added lines, 1 removed line.
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		@@ -264,11 +264,15 @@ type apiRoute struct {
		}

		// internalAPIRoutes is the internal face's served route table (spec §7, §14):
		// service-token auth, never Zero Trust. It carries both health probes.
		// service-token auth, never Zero Trust. It carries both health probes and the
		// metrics scrape.
		func (a *API) internalAPIRoutes() []apiRoute {
		return []apiRoute{
		{Method: "GET", Pattern: "/healthz", Public: true, h: a.handleHealthz},
		{Method: "GET", Pattern: "/readyz", Public: true, h: a.handleReadyz},
		// Prometheus scrape (felis_* collectors); public because a scrape carries
		// no token, internal-only so it is never exposed off-cluster.
		{Method: "GET", Pattern: "/metrics", Public: true, h: a.handleMetrics},

		{Method: "GET", Pattern: "/api/v1/servers", h: a.handleListServers},
		// The build Pod's context-fetch initContainer streams a submission's stored

0 → 100644

+34 −0

Changes for internal/api/metrics.go: 34 added lines, 0 removed lines.
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		package api

		import (
		"net/http"

		"felis.lolicon.best/internal/metrics"

		"github.com/prometheus/client_golang/prometheus"
		"github.com/prometheus/client_golang/prometheus/promhttp"
		)

		// apiMetricsHandler serves the felis_* collectors from a process-local registry.
		// The API process is the only producer of felis_image_build_failures_total (the
		// build reconcile loop lives in cmd/felis.reconcileBuilds), so this endpoint is
		// that counter's sole scrape path; the operator's :8080 carries the fleet
		// gauges instead.
		var apiMetricsHandler = newAPIMetricsHandler()

		func newAPIMetricsHandler() http.Handler {
		reg := prometheus.NewRegistry()
		// A fresh registry cannot already hold a collector, so Register's
		// AlreadyRegistered tolerance arm never triggers here.
		_ = metrics.Register(reg)
		return promhttp.HandlerFor(reg, promhttp.HandlerOpts{})
		}

		// handleMetrics is mounted as a Public route on the internal face (the same
		// stance as the health probes): the internal listener is ClusterIP-only and a
		// Prometheus scrape carries no token. The external face never serves metrics.
		// See docs/troubleshooting.md §14 for what to scrape and the alert rules that
		// consume these series.
		func (a API) handleMetrics(w http.ResponseWriter, r http.Request) {
		apiMetricsHandler.ServeHTTP(w, r)
		}

0 → 100644

+44 −0

Changes for internal/api/metrics_test.go: 44 added lines, 0 removed lines.
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		package api

		import (
		"net/http"
		"strings"
		"testing"

		"felis.lolicon.best/internal/metrics"
		)

		// TestMetricsEndpoint locks the scrape surface: the internal face serves the
		// felis_* collectors (the API process is felis_image_build_failures_total's
		// only producer), and the external face never serves metrics.
		func TestMetricsEndpoint(t *testing.T) {
		// Give every collector a sample so the exposition carries all four families:
		// an empty vector family is omitted from the text output entirely. The bumps
		// stay inside this test binary — the collectors are per-process globals.
		metrics.SyncServerGauge([]string{"Running"})
		metrics.StartDurationSeconds.Observe(3)
		metrics.ImageBuildFailuresTotal.Inc()
		metrics.ReaperWorldsDeletedTotal.Inc()

		a := &API{}

		w := do(a.InternalHandler(), "GET", "/metrics", "", nil)
		if w.Code != http.StatusOK {
		t.Fatalf("internal GET /metrics = %d, want 200", w.Code)
		}
		body := w.Body.String()
		for _, want := range []string{
		`felis_servers_total{state="Running"} 1`,
		"felis_start_duration_seconds_count 1",
		"felis_image_build_failures_total",
		"felis_reaper_worlds_deleted_total",
		} {
		if !strings.Contains(body, want) {
		t.Errorf("metrics exposition missing %q", want)
		}
		}

		if w := do(a.ExternalHandler(), "GET", "/metrics", "", nil); w.Code != http.StatusNotFound {
		t.Fatalf("external GET /metrics = %d, want 404 (metrics stay internal)", w.Code)
		}
		}