Enable http pprof connections when pprof-address is set.

Add flag to specify the address where those connections listen.

Signed-off-by: David Calavera <david.calavera@gmail.com>

api/http/pprof/pprof.go

@@ -0,0 +1,42 @@
+package pprof
+
+import (
+	"expvar"
+	"fmt"
+	"net/http"
+	"net/http/pprof"
+
+	"github.com/Sirupsen/logrus"
+)
+
+func Enable(address string) {
+	http.Handle("/", http.RedirectHandler("/debug/pprof", http.StatusMovedPermanently))
+
+	http.Handle("/debug/vars", http.HandlerFunc(expVars))
+	http.Handle("/debug/pprof/", http.HandlerFunc(pprof.Index))
+	http.Handle("/debug/pprof/cmdline", http.HandlerFunc(pprof.Cmdline))
+	http.Handle("/debug/pprof/profile", http.HandlerFunc(pprof.Profile))
+	http.Handle("/debug/pprof/symbol", http.HandlerFunc(pprof.Symbol))
+	http.Handle("/debug/pprof/block", pprof.Handler("block"))
+	http.Handle("/debug/pprof/heap", pprof.Handler("heap"))
+	http.Handle("/debug/pprof/goroutine", pprof.Handler("goroutine"))
+	http.Handle("/debug/pprof/threadcreate", pprof.Handler("threadcreate"))
+
+	go http.ListenAndServe(address, nil)
+	logrus.Debug("pprof listening in address %s", address)
+}
+
+// Replicated from expvar.go as not public.
+func expVars(w http.ResponseWriter, r *http.Request) {
+	first := true
+	w.Header().Set("Content-Type", "application/json; charset=utf-8")
+	fmt.Fprintf(w, "{\n")
+	expvar.Do(func(kv expvar.KeyValue) {
+		if !first {
+			fmt.Fprintf(w, ",\n")
+		}
+		first = false
+		fmt.Fprintf(w, "%q: %s", kv.Key, kv.Value)
+	})
+	fmt.Fprintf(w, "\n}\n")
+}

containerd/main.go

@@ -55,6 +55,10 @@ var daemonFlags = []cli.Flag{
 		Value: &cli.StringSlice{},
 		Usage: "specify additional runtime args",
 	},
+	cli.StringFlag{
+		Name:  "pprof-address",
+		Usage: "http address to listen for pprof events",
+	},
 }
 
 func main() {

containerd/main_linux.go

@@ -12,6 +12,7 @@ import (
 	"github.com/cloudfoundry/gosigar"
 	"github.com/codegangsta/cli"
 	"github.com/cyberdelia/go-metrics-graphite"
+	"github.com/docker/containerd/api/http/pprof"
 	"github.com/docker/containerd/osutils"
 	"github.com/docker/containerd/supervisor"
 	"github.com/rcrowley/go-metrics"
@@ -37,6 +38,10 @@ func setAppBefore(app *cli.App) {
 			if err := debugMetrics(context.GlobalDuration("metrics-interval"), context.GlobalString("graphite-address")); err != nil {
 				return err
 			}
+
+		}
+		if p := context.GlobalString("pprof-address"); len(p) > 0 {
+			pprof.Enable(p)
 		}
 		if err := checkLimits(); err != nil {
 			return err