feat(http): add config option to disable metrics endpoint in influxd

cmd/influxd/launcher/cmd.go

@@ -143,6 +143,7 @@ type InfluxdOpts struct {
 	SessionRenewDisabled bool
 
 	ProfilingDisabled bool
+	MetricsDisabled   bool
 
 	NatsPort            int
 	NatsMaxPayloadBytes int
@@ -189,6 +190,7 @@ func newOpts(viper *viper.Viper) *InfluxdOpts {
 		SessionRenewDisabled: false,
 
 		ProfilingDisabled: false,
+		MetricsDisabled:   false,
 
 		StoreType:   BoltStore,
 		SecretStore: BoltStore,
@@ -519,5 +521,13 @@ func (o *InfluxdOpts) bindCliOpts() []cli.Opt {
 			Desc:    "Don't expose debugging information over HTTP at /debug/pprof",
 			Default: o.ProfilingDisabled,
 		},
+
+		// Metrics config
+		{
+			DestP:   &o.MetricsDisabled,
+			Flag:    "metrics-disabled",
+			Desc:    "Don't expose metrics over HTTP at /metrics",
+			Default: o.MetricsDisabled,
+		},
 	}
 }

cmd/influxd/launcher/launcher.go

@@ -915,12 +915,12 @@ func (m *Launcher) run(ctx context.Context, opts *InfluxdOpts) (err error) {
 		)
 
 		httpLogger := m.log.With(zap.String("service", "http"))
-		m.httpServer.Handler = http.NewHandlerFromRegistry(
+		m.httpServer.Handler = http.NewRootHandler(
 			"platform",
-			m.reg,
 			http.WithLog(httpLogger),
 			http.WithAPIHandler(platformHandler),
 			http.WithPprofEnabled(!opts.ProfilingDisabled),
+			http.WithMetrics(m.reg, !opts.MetricsDisabled),
 		)
 
 		if opts.LogLevel == zap.DebugLevel {

http/handler.go

@@ -6,6 +6,7 @@ import (
 	"net/http"
 
 	"github.com/go-chi/chi"
+	"github.com/influxdata/influxdb/v2"
 	"github.com/influxdata/influxdb/v2/kit/prom"
 	kithttp "github.com/influxdata/influxdb/v2/kit/transport/http"
 	"github.com/influxdata/influxdb/v2/pprof"
@@ -39,17 +40,31 @@ type Handler struct {
 
 type (
 	handlerOpts struct {
-		log            *zap.Logger
-		apiHandler     http.Handler
-		healthHandler  http.Handler
-		metricsHandler http.Handler
-		readyHandler   http.Handler
-		pprofEnabled   bool
+		log           *zap.Logger
+		apiHandler    http.Handler
+		healthHandler http.Handler
+		readyHandler  http.Handler
+		pprofEnabled  bool
+
+		// NOTE: Track the registry even if metricsExposed = false
+		// so we can report HTTP metrics via telemetry.
+		metricsRegistry *prom.Registry
+		metricsExposed  bool
 	}
 
 	HandlerOptFn func(opts *handlerOpts)
 )
 
+func (o *handlerOpts) metricsHTTPHandler() http.Handler {
+	if !o.metricsExposed || o.metricsRegistry == nil {
+		handlerFunc := func(rw http.ResponseWriter, r *http.Request) {
+			kithttp.WriteErrorResponse(r.Context(), rw, influxdb.EForbidden, "metrics disabled")
+		}
+		return http.HandlerFunc(handlerFunc)
+	}
+	return o.metricsRegistry.HTTPHandler()
+}
+
 func WithLog(l *zap.Logger) HandlerOptFn {
 	return func(opts *handlerOpts) {
 		opts.log = l
@@ -68,34 +83,23 @@ func WithPprofEnabled(enabled bool) HandlerOptFn {
 	}
 }
 
-func WithHealthHandler(h http.Handler) HandlerOptFn {
-	return func(opts *handlerOpts) {
-		opts.healthHandler = h
-	}
-}
-
-func WithMetricsHandler(h http.Handler) HandlerOptFn {
-	return func(opts *handlerOpts) {
-		opts.metricsHandler = h
-	}
-}
-
-func WithReadyHandler(h http.Handler) HandlerOptFn {
+func WithMetrics(reg *prom.Registry, exposed bool) HandlerOptFn {
 	return func(opts *handlerOpts) {
-		opts.readyHandler = h
+		opts.metricsRegistry = reg
+		opts.metricsExposed = exposed
 	}
 }
 
-// NewHandlerFromRegistry creates a new handler with the given name,
-// and sets the /metrics endpoint to use the metrics from the given registry,
-// after self-registering h's metrics.
-func NewHandlerFromRegistry(name string, reg *prom.Registry, opts ...HandlerOptFn) *Handler {
+// NewRootHandler creates a new handler with the given name and registers any root-level
+// (non-API) routes enabled by the caller.
+func NewRootHandler(name string, opts ...HandlerOptFn) *Handler {
 	opt := handlerOpts{
-		log:            zap.NewNop(),
-		healthHandler:  http.HandlerFunc(HealthHandler),
-		metricsHandler: reg.HTTPHandler(),
-		readyHandler:   ReadyHandler(),
-		pprofEnabled:   false,
+		log:             zap.NewNop(),
+		healthHandler:   http.HandlerFunc(HealthHandler),
+		readyHandler:    ReadyHandler(),
+		pprofEnabled:    false,
+		metricsRegistry: nil,
+		metricsExposed:  false,
 	}
 	for _, o := range opts {
 		o(&opt)
@@ -113,7 +117,7 @@ func NewHandlerFromRegistry(name string, reg *prom.Registry, opts ...HandlerOptF
 		r.Use(
 			kithttp.Metrics(name, h.requests, h.requestDur),
 		)
-		r.Mount(MetricsPath, opt.metricsHandler)
+		r.Mount(MetricsPath, opt.metricsHTTPHandler())
 		r.Mount(ReadyPath, opt.readyHandler)
 		r.Mount(HealthPath, opt.healthHandler)
 		r.Mount(DebugPath, pprof.NewHTTPHandler(opt.pprofEnabled))
@@ -130,7 +134,9 @@ func NewHandlerFromRegistry(name string, reg *prom.Registry, opts ...HandlerOptF
 
 	h.r = r
 
-	reg.MustRegister(h.PrometheusCollectors()...)
+	if opt.metricsRegistry != nil {
+		opt.metricsRegistry.MustRegister(h.PrometheusCollectors()...)
+	}
 	return h
 }
 

http/handler_test.go

@@ -42,11 +42,11 @@ func TestHandler_ServeHTTP(t *testing.T) {
 	for _, tt := range tests {
 		t.Run(tt.name, func(t *testing.T) {
 			reg := prom.NewRegistry(zaptest.NewLogger(t))
-			h := NewHandlerFromRegistry(
+			h := NewRootHandler(
 				tt.fields.name,
-				reg,
 				WithLog(tt.fields.log),
 				WithAPIHandler(tt.fields.handler),
+				WithMetrics(reg, true),
 			)
 
 			tt.args.r.Header.Set("User-Agent", "ua1")