From 0323a5b8cf5e51464a1f8777adf729036d093551 Mon Sep 17 00:00:00 2001
From: Justin Li <jli.justinli@gmail.com>
Date: Fri, 26 Jun 2015 14:05:55 -0400
Subject: [PATCH] Add pprof debug HTTP endpoint

---
 chihaya.go | 20 ++------------------
 debug.go   | 52 ++++++++++++++++++++++++++++++++++++++++++++++++++++
 2 files changed, 54 insertions(+), 18 deletions(-)
 create mode 100644 debug.go

diff --git a/chihaya.go b/chihaya.go
index 50336cb..c594ba1 100644
--- a/chihaya.go
+++ b/chihaya.go
@@ -9,7 +9,6 @@ import (
 	"os"
 	"os/signal"
 	"runtime"
-	"runtime/pprof"
 	"sync"
 	"syscall"
 
@@ -27,13 +26,11 @@ import (
 
 var (
 	maxProcs   int
-	profile    string
 	configPath string
 )
 
 func init() {
 	flag.IntVar(&maxProcs, "maxprocs", runtime.NumCPU(), "maximum parallel threads")
-	flag.StringVar(&profile, "profile", "", "if non-empty, path to write profiling data")
 	flag.StringVar(&configPath, "config", "", "path to the configuration file")
 }
 
@@ -47,21 +44,8 @@ func Boot() {
 	runtime.GOMAXPROCS(maxProcs)
 	glog.V(1).Info("Set max threads to ", maxProcs)
 
-	if profile != "" {
-		f, err := os.Create(profile)
-		if err != nil {
-			glog.Fatalf("Failed to create profile file: %s\n", err)
-		}
-		defer f.Close()
-
-		pprof.StartCPUProfile(f)
-		glog.Info("Started profiling")
-
-		defer func() {
-			pprof.StopCPUProfile()
-			glog.Info("Stopped profiling")
-		}()
-	}
+	debugBoot()
+	defer debugShutdown()
 
 	cfg, err := config.Open(configPath)
 	if err != nil {
diff --git a/debug.go b/debug.go
new file mode 100644
index 0000000..9781e48
--- /dev/null
+++ b/debug.go
@@ -0,0 +1,52 @@
+package chihaya
+
+import (
+	"flag"
+	"net/http"
+	"os"
+	"runtime/pprof"
+
+	_ "net/http/pprof"
+
+	"github.com/golang/glog"
+)
+
+var (
+	profile     string
+	debugAddr   string
+	profileFile *os.File
+)
+
+func init() {
+	flag.StringVar(&profile, "profile", "", "if non-empty, path to write CPU profiling data")
+	flag.StringVar(&debugAddr, "debug", "", "if non-empty, address to serve debug data")
+}
+
+func debugBoot() {
+	var err error
+
+	if debugAddr != "" {
+		go func() {
+			glog.Info("Starting debug HTTP on ", debugAddr)
+			glog.Fatal(http.ListenAndServe(debugAddr, nil))
+		}()
+	}
+
+	if profile != "" {
+		profileFile, err = os.Create(profile)
+		if err != nil {
+			glog.Fatalf("Failed to create profile file: %s\n", err)
+		}
+
+		pprof.StartCPUProfile(profileFile)
+		glog.Info("Started profiling")
+	}
+}
+
+func debugShutdown() {
+	if profileFile != nil {
+		profileFile.Close()
+		pprof.StopCPUProfile()
+		glog.Info("Stopped profiling")
+	}
+}