Add opt-in pprof HTTP server for profiling

event-exporter/Makefile

@@ -20,7 +20,7 @@ ALL_ARCH=amd64 arm64
 IMAGE_NAME = event-exporter
 
 PREFIX ?= staging-k8s.gcr.io
-TAG ?= v0.5.11
+TAG ?= v0.5.13
 
 IMAGE=$(PREFIX)/$(IMAGE_NAME)
 

event-exporter/README.md

@@ -37,6 +37,14 @@ Event exporter has following options:
     Parameters for configuring sink
 ```
 
+Environment variables:
+
+```
+PPROF_SERVER_PORT string
+    Port on which to expose Go pprof HTTP profiling handler (e.g. "11123" or ":11123").
+    When unset, pprof server is disabled.
+```
+
 Set of flags for configuring sink is the following:
 
 ```

event-exporter/event_exporter_test.go

@@ -0,0 +1,59 @@
+/*
+Copyright 2017 Google Inc.
+
+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 main
+
+import (
+	"net/http"
+	"testing"
+)
+
+func TestStartPprofServer(t *testing.T) {
+	if s := startPprofServer(""); s != nil {
+		t.Errorf("startPprofServer(\"\") expected nil, got %v", s)
+	}
+
+	server := startPprofServer("11123")
+	if server == nil {
+		t.Fatalf("startPprofServer(\"11123\") returned nil")
+	}
+	defer server.Close()
+
+	if server.Addr != ":11123" {
+		t.Errorf("server.Addr = %q, want \":11123\"", server.Addr)
+	}
+
+	endpoints := []string{
+		"/debug/pprof/",
+		"/debug/pprof/cmdline",
+		"/debug/pprof/profile",
+		"/debug/pprof/symbol",
+		"/debug/pprof/trace",
+		"/debug/pprof/heap",
+		"/debug/pprof/goroutine",
+	}
+
+	for _, endpoint := range endpoints {
+		req, err := http.NewRequest("GET", endpoint, nil)
+		if err != nil {
+			t.Fatalf("Failed to create request for %s: %v", endpoint, err)
+		}
+		_, pattern := server.Handler.(*http.ServeMux).Handler(req)
+		if pattern == "" {
+			t.Errorf("pprof endpoint %q matched empty pattern on server handler", endpoint)
+		}
+	}
+}

event-exporter/main.go

@@ -17,9 +17,11 @@ limitations under the License.
 package main
 
 import (
+	"context"
 	"flag"
 	"fmt"
 	"net/http"
+	"net/http/pprof"
 	"os"
 	"os/signal"
 	"strings"
@@ -38,6 +40,10 @@ import (
 	"k8s.io/client-go/rest"
 )
 
+const (
+	pprofServerPortEnv = "PPROF_SERVER_PORT"
+)
+
 var (
 	resyncPeriod       = flag.Duration("resync-period", 1*time.Minute, "Reflector resync period")
 	sinkOpts           = flag.String("sink-opts", "", "Parameters for configuring sink")
@@ -140,9 +146,50 @@ func main() {
 
 	// Expose the Prometheus http endpoint
 	go func() {
-		http.Handle("/metrics", promhttp.Handler())
-		glog.Fatalf("Prometheus monitoring failed: %v", http.ListenAndServe(*prometheusEndpoint, nil))
+		promMux := http.NewServeMux()
+		promMux.Handle("/metrics", promhttp.Handler())
+		glog.Fatalf("Prometheus monitoring failed: %v", http.ListenAndServe(*prometheusEndpoint, promMux))
 	}()
 
+	// Start pprof server if PPROF_SERVER_PORT is specified
+	if pprofPort := os.Getenv(pprofServerPortEnv); pprofPort != "" {
+		pprofServer := startPprofServer(pprofPort)
+		if pprofServer != nil {
+			go func() {
+				<-stopCh
+				ctx, cancel := context.WithTimeout(context.Background(), 5*time.Second)
+				defer cancel()
+				pprofServer.Shutdown(ctx)
+			}()
+		}
+	}
+
 	eventExporter.Run(stopCh)
 }
+
+func startPprofServer(port string) *http.Server {
+	port = strings.TrimSpace(port)
+	if port == "" {
+		return nil
+	}
+	if !strings.HasPrefix(port, ":") {
+		port = ":" + port
+	}
+	mux := http.NewServeMux()
+	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)
+	server := &http.Server{
+		Addr:    port,
+		Handler: mux,
+	}
+	go func() {
+		glog.Infof("Starting pprof HTTP server on %s", port)
+		if err := server.ListenAndServe(); err != nil && err != http.ErrServerClosed {
+			glog.Errorf("pprof server failed: %v", err)
+		}
+	}()
+	return server
+}