✨ Introduce pprof server to manager

pkg/manager/internal.go

@@ -23,6 +23,7 @@ import (
 	"fmt"
 	"net"
 	"net/http"
+	"net/http/pprof"
 	"sync"
 	"sync/atomic"
 	"time"
@@ -106,6 +107,9 @@ type controllerManager struct {
 	// Healthz probe handler
 	healthzHandler *healthz.Handler
 
+	// pprofListener is used to serve pprof
+	pprofListener net.Listener
+
 	// controllerConfig are the global controller options.
 	controllerConfig config.Controller
 
@@ -343,6 +347,24 @@ func (cm *controllerManager) serveHealthProbes() {
 	go cm.httpServe("health probe", cm.logger, server, cm.healthProbeListener)
 }
 
+func (cm *controllerManager) addPprofServer() error {
+	mux := http.NewServeMux()
+	srv := httpserver.New(mux)
+
+	mux.HandleFunc("/debug/pprof/", pprof.Index)
+	mux.HandleFunc("/debug/pprof/cmdline", pprof.Cmdline)
+	mux.HandleFunc("/debug/pprof/profile", pprof.Profile)
+	mux.HandleFunc("/debug/pprof/symbol", pprof.Symbol)
+	mux.HandleFunc("/debug/pprof/trace", pprof.Trace)
+
+	return cm.add(&server{
+		Kind:     "pprof",
+		Log:      cm.logger,
+		Server:   srv,
+		Listener: cm.pprofListener,
+	})
+}
+
 func (cm *controllerManager) httpServe(kind string, log logr.Logger, server *http.Server, ln net.Listener) {
 	log = log.WithValues("kind", kind, "addr", ln.Addr())
 
@@ -440,6 +462,13 @@ func (cm *controllerManager) Start(ctx context.Context) (err error) {
 		cm.serveHealthProbes()
 	}
 
+	// Add pprof server
+	if cm.pprofListener != nil {
+		if err := cm.addPprofServer(); err != nil {
+			return fmt.Errorf("failed to add pprof server: %w", err)
+		}
+	}
+
 	// First start any webhook servers, which includes conversion, validation, and defaulting
 	// webhooks that are registered.
 	//

pkg/manager/manager.go

@@ -233,6 +233,13 @@ type Options struct {
 	// Liveness probe endpoint name, defaults to "healthz"
 	LivenessEndpointName string
 
+	// PprofBindAddress is the TCP address that the controller should bind to
+	// for serving pprof.
+	// It can be set to "" or "0" to disable the pprof serving.
+	// Since pprof may contain sensitive information, make sure to protect it
+	// before exposing it to public.
+	PprofBindAddress string
+
 	// Port is the port that the webhook server serves at.
 	// It is used to set webhook.Server.Port if WebhookServer is not set.
 	Port int
@@ -308,6 +315,7 @@ type Options struct {
 	newResourceLock        func(config *rest.Config, recorderProvider recorder.Provider, options leaderelection.Options) (resourcelock.Interface, error)
 	newMetricsListener     func(addr string) (net.Listener, error)
 	newHealthProbeListener func(addr string) (net.Listener, error)
+	newPprofListener       func(addr string) (net.Listener, error)
 }
 
 // BaseContextFunc is a function used to provide a base Context to Runnables
@@ -417,6 +425,13 @@ func New(config *rest.Config, options Options) (Manager, error) {
 		return nil, err
 	}
 
+	// Create pprof listener. This will throw an error if the bind
+	// address is invalid or already in use.
+	pprofListener, err := options.newPprofListener(options.PprofBindAddress)
+	if err != nil {
+		return nil, fmt.Errorf("failed to new pprof listener: %w", err)
+	}
+
 	errChan := make(chan error)
 	runnables := newRunnables(options.BaseContext, errChan)
 
@@ -444,6 +459,7 @@ func New(config *rest.Config, options Options) (Manager, error) {
 		healthProbeListener:           healthProbeListener,
 		readinessEndpointName:         options.ReadinessEndpointName,
 		livenessEndpointName:          options.LivenessEndpointName,
+		pprofListener:                 pprofListener,
 		gracefulShutdownTimeout:       *options.GracefulShutdownTimeout,
 		internalProceduresStop:        make(chan struct{}),
 		leaderElectionStopped:         make(chan struct{}),
@@ -574,6 +590,19 @@ func defaultHealthProbeListener(addr string) (net.Listener, error) {
 	return ln, nil
 }
 
+// defaultPprofListener creates the default pprof listener bound to the given address.
+func defaultPprofListener(addr string) (net.Listener, error) {
+	if addr == "" || addr == "0" {
+		return nil, nil
+	}
+
+	ln, err := net.Listen("tcp", addr)
+	if err != nil {
+		return nil, fmt.Errorf("error listening on %s: %w", addr, err)
+	}
+	return ln, nil
+}
+
 // defaultBaseContext is used as the BaseContext value in Options if one
 // has not already been set.
 func defaultBaseContext() context.Context {
@@ -634,6 +663,10 @@ func setOptionsDefaults(options Options) Options {
 		options.newHealthProbeListener = defaultHealthProbeListener
 	}
 
+	if options.newPprofListener == nil {
+		options.newPprofListener = defaultPprofListener
+	}
+
 	if options.GracefulShutdownTimeout == nil {
 		gracefulShutdownTimeout := defaultGracefulShutdownPeriod
 		options.GracefulShutdownTimeout = &gracefulShutdownTimeout

pkg/manager/manager_test.go

@@ -148,6 +148,7 @@ var _ = Describe("manger.Manager", func() {
 					LeaderElectionID:        "test-leader-election-id-2",
 					HealthProbeBindAddress:  "0",
 					MetricsBindAddress:      "0",
+					PprofBindAddress:        "0",
 				})
 				Expect(err).To(BeNil())
 
@@ -193,6 +194,7 @@ var _ = Describe("manger.Manager", func() {
 					LeaderElectionID:        "test-leader-election-id-3",
 					HealthProbeBindAddress:  "0",
 					MetricsBindAddress:      "0",
+					PprofBindAddress:        "0",
 				})
 				Expect(err).To(BeNil())
 
@@ -227,6 +229,7 @@ var _ = Describe("manger.Manager", func() {
 					},
 					HealthProbeBindAddress: "0",
 					MetricsBindAddress:     "0",
+					PprofBindAddress:       "0",
 				})
 				Expect(err).ToNot(HaveOccurred())
 				Expect(m1).ToNot(BeNil())
@@ -247,6 +250,7 @@ var _ = Describe("manger.Manager", func() {
 					},
 					HealthProbeBindAddress: "0",
 					MetricsBindAddress:     "0",
+					PprofBindAddress:       "0",
 				})
 				Expect(err).ToNot(HaveOccurred())
 				Expect(m2).ToNot(BeNil())
@@ -1280,6 +1284,99 @@ var _ = Describe("manger.Manager", func() {
 		})
 	})
 
+	Context("should start serving pprof", func() {
+		var listener net.Listener
+		var opts Options
+
+		BeforeEach(func() {
+			listener = nil
+			opts = Options{
+				newPprofListener: func(addr string) (net.Listener, error) {
+					var err error
+					listener, err = defaultPprofListener(addr)
+					return listener, err
+				},
+			}
+		})
+
+		AfterEach(func() {
+			if listener != nil {
+				listener.Close()
+			}
+		})
+
+		It("should stop serving pprof when stop is called", func() {
+			opts.PprofBindAddress = ":0"
+			m, err := New(cfg, opts)
+			Expect(err).NotTo(HaveOccurred())
+
+			ctx, cancel := context.WithCancel(context.Background())
+			go func() {
+				defer GinkgoRecover()
+				Expect(m.Start(ctx)).NotTo(HaveOccurred())
+			}()
+			<-m.Elected()
+
+			// Check the pprof started
+			endpoint := fmt.Sprintf("http://%s", listener.Addr().String())
+			_, err = http.Get(endpoint)
+			Expect(err).NotTo(HaveOccurred())
+
+			// Shutdown the server
+			cancel()
+
+			// Expect the pprof server to shutdown
+			Eventually(func() error {
+				_, err = http.Get(endpoint)
+				return err
+			}, 10*time.Second).ShouldNot(Succeed())
+		})
+
+		It("should serve pprof endpoints", func() {
+			opts.PprofBindAddress = ":0"
+			m, err := New(cfg, opts)
+			Expect(err).NotTo(HaveOccurred())
+
+			ctx, cancel := context.WithCancel(context.Background())
+			defer cancel()
+			go func() {
+				defer GinkgoRecover()
+				Expect(m.Start(ctx)).NotTo(HaveOccurred())
+			}()
+			<-m.Elected()
+
+			pprofIndexEndpoint := fmt.Sprintf("http://%s/debug/pprof/", listener.Addr().String())
+			resp, err := http.Get(pprofIndexEndpoint)
+			Expect(err).NotTo(HaveOccurred())
+			defer resp.Body.Close()
+			Expect(resp.StatusCode).To(Equal(http.StatusOK))
+
+			pprofCmdlineEndpoint := fmt.Sprintf("http://%s/debug/pprof/cmdline", listener.Addr().String())
+			resp, err = http.Get(pprofCmdlineEndpoint)
+			Expect(err).NotTo(HaveOccurred())
+			defer resp.Body.Close()
+			Expect(resp.StatusCode).To(Equal(http.StatusOK))
+
+			pprofProfileEndpoint := fmt.Sprintf("http://%s/debug/pprof/profile", listener.Addr().String())
+			resp, err = http.Get(pprofProfileEndpoint)
+			Expect(err).NotTo(HaveOccurred())
+			defer resp.Body.Close()
+			Expect(resp.StatusCode).To(Equal(http.StatusOK))
+
+			pprofSymbolEndpoint := fmt.Sprintf("http://%s/debug/pprof/symbol", listener.Addr().String())
+			resp, err = http.Get(pprofSymbolEndpoint)
+			Expect(err).NotTo(HaveOccurred())
+			defer resp.Body.Close()
+			Expect(resp.StatusCode).To(Equal(http.StatusOK))
+
+			pprofTraceEndpoint := fmt.Sprintf("http://%s/debug/pprof/trace", listener.Addr().String())
+			resp, err = http.Get(pprofTraceEndpoint)
+			Expect(err).NotTo(HaveOccurred())
+			defer resp.Body.Close()
+			Expect(resp.StatusCode).To(Equal(http.StatusOK))
+		})
+	})
+
 	Describe("Add", func() {
 		It("should immediately start the Component if the Manager has already Started another Component",
 			func() {

pkg/manager/server.go

@@ -0,0 +1,61 @@
+/*
+Copyright 2022 The Kubernetes Authors.
+
+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.
+*/
+
+package manager
+
+import (
+	"context"
+	"errors"
+	"net"
+	"net/http"
+
+	"github.com/go-logr/logr"
+)
+
+// server is a general purpose HTTP server Runnable for a manager
+// to serve some internal handlers such as health probes, metrics and profiling.
+type server struct {
+	Kind     string
+	Log      logr.Logger
+	Server   *http.Server
+	Listener net.Listener
+}
+
+func (s *server) Start(ctx context.Context) error {
+	log := s.Log.WithValues("kind", s.Kind, "addr", s.Listener.Addr())
+
+	serverShutdown := make(chan struct{})
+	go func() {
+		<-ctx.Done()
+		log.Info("shutting down server")
+		if err := s.Server.Shutdown(context.Background()); err != nil {
+			log.Error(err, "error shutting down server")
+		}
+		close(serverShutdown)
+	}()
+
+	log.Info("starting server")
+	if err := s.Server.Serve(s.Listener); err != nil && !errors.Is(err, http.ErrServerClosed) {
+		return err
+	}
+
+	<-serverShutdown
+	return nil
+}
+
+func (s *server) NeedLeaderElection() bool {
+	return false
+}