Add events api to shim

Signed-off-by: Michael Crosby <crosbymichael@gmail.com>

cmd/containerd-shim/main.go

@@ -55,37 +55,12 @@ func main() {
 			server = grpc.NewServer()
 			sv     = shim.NewService()
 		)
+		logrus.Debug("registering grpc server")
 		apishim.RegisterShimServer(server, sv)
-		l, err := utils.CreateUnixSocket("shim.sock")
-		if err != nil {
+		if err := serve(server, "shim.sock"); err != nil {
 			return err
 		}
-		go func() {
-			defer l.Close()
-			if err := server.Serve(l); err != nil {
-				l.Close()
-				logrus.WithError(err).Fatal("containerd-shim: GRPC server failure")
-			}
-		}()
-		for s := range signals {
-			logrus.WithField("signal", s).Debug("received signal")
-			switch s {
-			case syscall.SIGCHLD:
-				exits, err := utils.Reap(false)
-				if err != nil {
-					logrus.WithError(err).Error("reap exit status")
-				}
-				for _, e := range exits {
-					if err := sv.ProcessExit(e); err != nil {
-						return err
-					}
-				}
-			case syscall.SIGTERM, syscall.SIGINT:
-				server.GracefulStop()
-				return nil
-			}
-		}
-		return nil
+		return handleSignals(signals, server, sv)
 	}
 	if err := app.Run(os.Args); err != nil {
 		fmt.Fprintf(os.Stderr, "containerd-shim: %s\n", err)
@@ -104,3 +79,49 @@ func setupSignals() (chan os.Signal, error) {
 	}
 	return signals, nil
 }
+
+// serve serves the grpc API over a unix socket at the provided path
+// this function does not block
+func serve(server *grpc.Server, path string) error {
+	l, err := utils.CreateUnixSocket(path)
+	if err != nil {
+		return err
+	}
+	logrus.WithField("socket", path).Debug("serving api on unix socket")
+	go func() {
+		defer l.Close()
+		if err := server.Serve(l); err != nil {
+			l.Close()
+			logrus.WithError(err).Fatal("containerd-shim: GRPC server failure")
+		}
+	}()
+	return nil
+}
+
+func handleSignals(signals chan os.Signal, server *grpc.Server, service *shim.Service) error {
+	for s := range signals {
+		logrus.WithField("signal", s).Debug("received signal")
+		switch s {
+		case syscall.SIGCHLD:
+			exits, err := utils.Reap(false)
+			if err != nil {
+				logrus.WithError(err).Error("reap exit status")
+			}
+			for _, e := range exits {
+				logrus.WithFields(logrus.Fields{
+					"status": e.Status,
+					"pid":    e.Pid,
+				}).Debug("process exited")
+				if err := service.ProcessExit(e); err != nil {
+					return err
+				}
+			}
+		case syscall.SIGTERM, syscall.SIGINT:
+			// TODO: should we forward signals to the processes if they are still running?
+			// i.e. machine reboot
+			server.GracefulStop()
+			return nil
+		}
+	}
+	return nil
+}

cmd/ctr/shim.go

@@ -18,6 +18,21 @@ import (
 	"github.com/urfave/cli"
 )
 
+var fifoFlags = []cli.Flag{
+	cli.StringFlag{
+		Name:  "stdin",
+		Usage: "specify the path to the stdin fifo",
+	},
+	cli.StringFlag{
+		Name:  "stdout",
+		Usage: "specify the path to the stdout fifo",
+	},
+	cli.StringFlag{
+		Name:  "stderr",
+		Usage: "specify the path to the stderr fifo",
+	},
+}
+
 var shimCommand = cli.Command{
 	Name:  "shim",
 	Usage: "interact with a shim directly",
@@ -41,7 +56,7 @@ var shimCommand = cli.Command{
 var shimCreateCommand = cli.Command{
 	Name:  "create",
 	Usage: "create a container with a shim",
-	Flags: []cli.Flag{
+	Flags: append(fifoFlags,
 		cli.StringFlag{
 			Name:  "bundle",
 			Usage: "bundle path for the container",
@@ -51,7 +66,11 @@ var shimCreateCommand = cli.Command{
 			Value: "runc",
 			Usage: "runtime to use for the container",
 		},
-	},
+		cli.BoolFlag{
+			Name:  "attach,a",
+			Usage: "stay attached to the container and open the fifos",
+		},
+	),
 	Action: func(context *cli.Context) error {
 		id := context.Args().First()
 		if id == "" {
@@ -61,15 +80,25 @@ var shimCreateCommand = cli.Command{
 		if err != nil {
 			return err
 		}
+		wg, err := prepareStdio(context.String("stdin"), context.String("stdout"), context.String("stderr"), false)
+		if err != nil {
+			return err
+		}
 		r, err := service.Create(gocontext.Background(), &shim.CreateRequest{
 			ID:      id,
 			Bundle:  context.String("bundle"),
 			Runtime: context.String("runtime"),
+			Stdin:   context.String("stdin"),
+			Stdout:  context.String("stdout"),
+			Stderr:  context.String("stderr"),
 		})
 		if err != nil {
 			return err
 		}
 		fmt.Printf("container created with id %s and pid %d\n", id, r.Pid)
+		if context.Bool("attach") {
+			wg.Wait()
+		}
 		return nil
 	},
 }
@@ -99,7 +128,7 @@ var shimDeleteCommand = cli.Command{
 		if err != nil {
 			return err
 		}
-		fmt.Printf("container deleted and returned exit status %d", r.ExitStatus)
+		fmt.Printf("container deleted and returned exit status %d\n", r.ExitStatus)
 		return nil
 	},
 }

cmd/ctr/utils.go

@@ -115,7 +115,6 @@ func getTempDir(id string) (string, error) {
 	if err != nil {
 		return "", err
 	}
-
 	tmpDir, err := ioutil.TempDir(filepath.Join(os.TempDir(), "ctr"), fmt.Sprintf("%s-", id))
 	if err != nil {
 		return "", err