ctr: add events command

This simply print all events generated by containerd

Signed-off-by: Kenfe-Mickael Laventure <mickael.laventure@gmail.com>

cmd/ctr/events.go

@@ -0,0 +1,61 @@
+package main
+
+import (
+	"bytes"
+	"encoding/json"
+	"fmt"
+
+	"github.com/nats-io/go-nats"
+	"github.com/urfave/cli"
+)
+
+var eventsCommand = cli.Command{
+	Name:  "events",
+	Usage: "display containerd events",
+	Flags: []cli.Flag{
+		cli.StringFlag{
+			Name:  "subject, s",
+			Usage: "subjects filter",
+			Value: "containerd.>",
+		},
+	},
+	Action: func(context *cli.Context) error {
+		nc, err := nats.Connect(nats.DefaultURL)
+		if err != nil {
+			return err
+		}
+		nec, err := nats.NewEncodedConn(nc, nats.JSON_ENCODER)
+		if err != nil {
+			nc.Close()
+			return err
+		}
+		defer nec.Close()
+
+		evCh := make(chan *nats.Msg, 64)
+		sub, err := nec.Subscribe(context.String("subject"), func(e *nats.Msg) {
+			evCh <- e
+		})
+		if err != nil {
+			return err
+		}
+		defer sub.Unsubscribe()
+
+		for {
+			e, more := <-evCh
+			if !more {
+				break
+			}
+
+			var prettyJSON bytes.Buffer
+
+			err := json.Indent(&prettyJSON, e.Data, "", "\t")
+			if err != nil {
+				fmt.Println(string(e.Data))
+			} else {
+				fmt.Println(prettyJSON.String())
+			}
+		}
+
+		return nil
+	},
+}

cmd/ctr/exec.go

@@ -18,6 +18,10 @@ var execCommand = cli.Command{
 			Name:  "id, i",
 			Usage: "target container id",
 		},
+		cli.StringFlag{
+			Name:  "pid, p",
+			Usage: "new process id",
+		},
 		cli.StringFlag{
 			Name:  "cwd, c",
 			Usage: "current working directory for the process",
@@ -48,6 +52,7 @@ var execCommand = cli.Command{
 		sOpts := &execution.StartProcessRequest{
 			ContainerID: id,
 			Process: &execution.Process{
+				ID:       context.String("pid"),
 				Cwd:      context.String("cwd"),
 				Terminal: context.Bool("tty"),
 				Args:     context.Args(),

cmd/ctr/main.go

@@ -36,6 +36,7 @@ containerd client
 	app.Commands = []cli.Command{
 		runCommand,
 		execCommand,
+		eventsCommand,
 	}
 	app.Before = func(context *cli.Context) error {
 		if context.GlobalBool("debug") {