refactor(cli): break down observability.startMetrics() (#3196)

Motivation: reduce the function complexity for the linter, so additional functionality can be added to `startMetrics()` No functional changes. Changes and transformations: - Break down observability.startMetrics() into: maybeStartListener(). maybeStartMetricsPusher() and maybeStartTraceExporter(). - Inline observabilityFlags.getExporter in maybeStartTraceExporter. - Only create resource when exporter is non-nil. - Simplify maybeStartListener: reduce indentation by returning early. - Simplify maybeStartMetricsPusher: reduce indentation by returning early.
2026-05-24 06:34:46 -04:00 · 2023-08-06 11:44:31 -07:00
parent 0d2a7c83a0
commit 9f33f70eaa
1 changed files with 86 additions and 74 deletions
--- a/cli/observability_flags.go
+++ b/cli/observability_flags.go
@@ -79,72 +79,98 @@ func (c *observabilityFlags) setup(svc appServices, app *kingpin.Application) {
 }

 func (c *observabilityFlags) startMetrics(ctx context.Context) error {
-	if c.metricsListenAddr != "" {
-		m := mux.NewRouter()
-		initPrometheus(m)
+	c.maybeStartListener(ctx)

-		if c.enablePProf {
-			m.HandleFunc("/debug/pprof/", pprof.Index)
-			m.HandleFunc("/debug/pprof/cmdline", pprof.Cmdline)
-			m.HandleFunc("/debug/pprof/profile", pprof.Profile)
-			m.HandleFunc("/debug/pprof/symbol", pprof.Symbol)
-			m.HandleFunc("/debug/pprof/trace", pprof.Trace)
-			m.HandleFunc("/debug/pprof/{cmd}", pprof.Index) // special handling for Gorilla mux, see https://stackoverflow.com/questions/30560859/cant-use-go-tool-pprof-with-an-existing-server/71032595#71032595
-		}
-
-		log(ctx).Infof("starting prometheus metrics on %v", c.metricsListenAddr)
-
-		go http.ListenAndServe(c.metricsListenAddr, m) //nolint:errcheck,gosec
-	}
-
-	if c.metricsPushAddr != "" {
-		c.stopPusher = make(chan struct{})
-		c.pusherWG.Add(1)
-
-		pusher := push.New(c.metricsPushAddr, c.metricsJob)
-
-		pusher.Gatherer(prometheus.DefaultGatherer)
-
-		for _, g := range c.metricsGroupings {
-			const nParts = 2
-
-			parts := strings.SplitN(g, ":", nParts)
-			if len(parts) != nParts {
-				return errors.Errorf("grouping must be name:value")
-			}
-
-			name := parts[0]
-			val := parts[1]
-
-			pusher.Grouping(name, val)
-		}
-
-		if c.metricsPushUsername != "" {
-			pusher.BasicAuth(c.metricsPushUsername, c.metricsPushPassword)
-		}
-
-		if c.metricsPushFormat != "" {
-			pusher.Format(metricsPushFormats[c.metricsPushFormat])
-		}
-
-		log(ctx).Infof("starting prometheus pusher on %v every %v", c.metricsPushAddr, c.metricsPushInterval)
-		c.pushOnce(ctx, "initial", pusher)
-
-		go c.pushPeriodically(ctx, pusher)
-	}
-
-	se, err := c.getSpanExporter()
-	if err != nil {
+	if err := c.maybeStartMetricsPusher(ctx); err != nil {
 		return err
 	}

-	r := resource.NewWithAttributes(
-		semconv.SchemaURL,
-		semconv.ServiceNameKey.String("kopia"),
-		semconv.ServiceVersionKey.String(repo.BuildVersion),
-	)
+	return c.maybeStartTraceExporter()
+}
+
+// Starts observability listener when a listener address is specified.
+func (c *observabilityFlags) maybeStartListener(ctx context.Context) {
+	if c.metricsListenAddr == "" {
+		return
+	}
+
+	m := mux.NewRouter()
+	initPrometheus(m)
+
+	if c.enablePProf {
+		m.HandleFunc("/debug/pprof/", pprof.Index)
+		m.HandleFunc("/debug/pprof/cmdline", pprof.Cmdline)
+		m.HandleFunc("/debug/pprof/profile", pprof.Profile)
+		m.HandleFunc("/debug/pprof/symbol", pprof.Symbol)
+		m.HandleFunc("/debug/pprof/trace", pprof.Trace)
+		m.HandleFunc("/debug/pprof/{cmd}", pprof.Index) // special handling for Gorilla mux, see https://stackoverflow.com/questions/30560859/cant-use-go-tool-pprof-with-an-existing-server/71032595#71032595
+	}
+
+	log(ctx).Infof("starting prometheus metrics on %v", c.metricsListenAddr)
+
+	go http.ListenAndServe(c.metricsListenAddr, m) //nolint:errcheck,gosec
+}
+
+func (c *observabilityFlags) maybeStartMetricsPusher(ctx context.Context) error {
+	if c.metricsPushAddr == "" {
+		return nil
+	}
+
+	c.stopPusher = make(chan struct{})
+	c.pusherWG.Add(1)
+
+	pusher := push.New(c.metricsPushAddr, c.metricsJob)
+
+	pusher.Gatherer(prometheus.DefaultGatherer)
+
+	for _, g := range c.metricsGroupings {
+		const nParts = 2
+
+		parts := strings.SplitN(g, ":", nParts)
+		if len(parts) != nParts {
+			return errors.Errorf("grouping must be name:value")
+		}
+
+		name := parts[0]
+		val := parts[1]
+
+		pusher.Grouping(name, val)
+	}
+
+	if c.metricsPushUsername != "" {
+		pusher.BasicAuth(c.metricsPushUsername, c.metricsPushPassword)
+	}
+
+	if c.metricsPushFormat != "" {
+		pusher.Format(metricsPushFormats[c.metricsPushFormat])
+	}
+
+	log(ctx).Infof("starting prometheus pusher on %v every %v", c.metricsPushAddr, c.metricsPushInterval)
+	c.pushOnce(ctx, "initial", pusher)
+
+	go c.pushPeriodically(ctx, pusher)
+
+	return nil
+}
+
+func (c *observabilityFlags) maybeStartTraceExporter() error {
+	if !c.enableJaeger {
+		return nil
+	}
+
+	// Create the Jaeger exporter
+	se, err := jaeger.New(jaeger.WithCollectorEndpoint())
+	if err != nil {
+		return errors.Wrap(err, "unable to create Jaeger exporter")
+	}

 	if se != nil {
+		r := resource.NewWithAttributes(
+			semconv.SchemaURL,
+			semconv.ServiceNameKey.String("kopia"),
+			semconv.ServiceVersionKey.String(repo.BuildVersion),
+		)
+
 		tp := trace.NewTracerProvider(
 			trace.WithBatcher(se),
 			trace.WithResource(r),
@@ -158,20 +184,6 @@ func (c *observabilityFlags) startMetrics(ctx context.Context) error {
 	return nil
 }

-func (c *observabilityFlags) getSpanExporter() (trace.SpanExporter, error) {
-	if c.enableJaeger {
-		// Create the Jaeger exporter
-		exp, err := jaeger.New(jaeger.WithCollectorEndpoint())
-		if err != nil {
-			return nil, errors.Wrap(err, "unable to create Jaeger exporter")
-		}
-
-		return exp, nil
-	}
-
-	return nil, nil
-}
-
 func (c *observabilityFlags) stopMetrics(ctx context.Context) {
 	if c.stopPusher != nil {
 		close(c.stopPusher)