ctr pprof support added

Signed-off-by: Kunal Kushwaha <kushwaha_kunal_v7@lab.ntt.co.jp>

cmd/ctr/main.go

@@ -41,6 +41,7 @@ containerd client
 		listCommand,
 		inspectCommand,
 		shimCommand,
+		pprofCommand,
 	}
 	app.Before = func(context *cli.Context) error {
 		if context.GlobalBool("debug") {

cmd/ctr/pprof.go

@@ -0,0 +1,181 @@
+package main
+
+import (
+	"fmt"
+	"io"
+	"net"
+	"net/http"
+	"os"
+	"time"
+
+	"github.com/urfave/cli"
+)
+
+type pprofDialer struct {
+	proto string
+	addr  string
+}
+
+var pprofCommand = cli.Command{
+	Name:  "pprof",
+	Usage: "provides golang pprof outputs for containerd",
+	Flags: []cli.Flag{
+		cli.StringFlag{
+			Name:  "debug-socket, d",
+			Usage: "socket path for containerd's debug server",
+			Value: "/run/containerd/containerd-debug.sock",
+		},
+	},
+	Subcommands: []cli.Command{
+		pprofGoroutinesCommand,
+		pprofHeapCommand,
+		pprofProfileCommand,
+		pprofTraceCommand,
+		pprofBlockCommand,
+		pprofThreadcreateCommand,
+	},
+}
+
+var pprofGoroutinesCommand = cli.Command{
+	Name:  "goroutines",
+	Usage: "dump goroutine stack dump",
+	Action: func(context *cli.Context) error {
+		client := getPProfClient(context)
+
+		output, err := httpGetRequest(client, "/debug/pprof/goroutine?debug=2")
+		if err != nil {
+			return err
+		}
+		defer output.Close()
+		if _, err := io.Copy(os.Stdout, output); err != nil {
+			return err
+		}
+		return nil
+	},
+}
+
+var pprofHeapCommand = cli.Command{
+	Name:  "heap",
+	Usage: "dump heap profile",
+	Action: func(context *cli.Context) error {
+		client := getPProfClient(context)
+
+		output, err := httpGetRequest(client, "/debug/pprof/heap")
+		if err != nil {
+			return err
+		}
+		defer output.Close()
+		if _, err := io.Copy(os.Stdout, output); err != nil {
+			return err
+		}
+		return nil
+	},
+}
+
+var pprofProfileCommand = cli.Command{
+	Name:  "profile",
+	Usage: "CPU profile",
+	Action: func(context *cli.Context) error {
+		client := getPProfClient(context)
+
+		output, err := httpGetRequest(client, "/debug/pprof/profile")
+		if err != nil {
+			return err
+		}
+		defer output.Close()
+		if _, err := io.Copy(os.Stdout, output); err != nil {
+			return err
+		}
+		return nil
+	},
+}
+
+var pprofTraceCommand = cli.Command{
+	Name:  "trace",
+	Usage: "collects execution trace",
+	Flags: []cli.Flag{
+		cli.DurationFlag{
+			Name:  "seconds,s",
+			Usage: "Trace time (seconds)",
+			Value: time.Duration(5 * time.Second),
+		},
+	},
+	Action: func(context *cli.Context) error {
+		client := getPProfClient(context)
+
+		seconds := context.Duration("seconds").Seconds()
+		uri := fmt.Sprintf("/debug/pprof/trace?seconds=%v", seconds)
+		output, err := httpGetRequest(client, uri)
+		if err != nil {
+			return err
+		}
+		defer output.Close()
+		if _, err := io.Copy(os.Stdout, output); err != nil {
+			return err
+		}
+		return nil
+
+	},
+}
+
+var pprofBlockCommand = cli.Command{
+	Name:  "block",
+	Usage: "goroutine blocking profile",
+	Action: func(context *cli.Context) error {
+		client := getPProfClient(context)
+
+		output, err := httpGetRequest(client, "/debug/pprof/block")
+		if err != nil {
+			return err
+		}
+		defer output.Close()
+		if _, err := io.Copy(os.Stdout, output); err != nil {
+			return err
+		}
+		return nil
+	},
+}
+
+var pprofThreadcreateCommand = cli.Command{
+	Name:  "threadcreate",
+	Usage: "goroutine blocking profile",
+	Action: func(context *cli.Context) error {
+		client := getPProfClient(context)
+
+		output, err := httpGetRequest(client, "/debug/pprof/threadcreate")
+		if err != nil {
+			return err
+		}
+		defer output.Close()
+		if _, err := io.Copy(os.Stdout, output); err != nil {
+			return err
+		}
+		return nil
+	},
+}
+
+func (d *pprofDialer) pprofDial(proto, addr string) (conn net.Conn, err error) {
+	return net.Dial(d.proto, d.addr)
+}
+
+func getPProfClient(context *cli.Context) *http.Client {
+	addr := context.GlobalString("debug-socket")
+	dialer := pprofDialer{"unix", addr}
+
+	tr := &http.Transport{
+		Dial: dialer.pprofDial,
+	}
+	client := &http.Client{Transport: tr}
+	return client
+}
+
+func httpGetRequest(client *http.Client, request string) (io.ReadCloser, error) {
+	resp, err := client.Get("http://." + request)
+	if err != nil {
+		return nil, err
+	}
+	if resp.StatusCode != 200 {
+		return nil, fmt.Errorf("%s", resp.Status)
+	}
+	return resp.Body, nil
+}