Add kpod wait

Waits on one or more containers to stop and prints the container's
return code

Signed-off-by: baude <bbaude@redhat.com>

cmd/kpod/main.go

@@ -54,6 +54,7 @@ func main() {
 		umountCommand,
 		unpauseCommand,
 		versionCommand,
+		waitCommand,
 	}
 	app.Before = func(c *cli.Context) error {
 		logrus.SetLevel(logrus.ErrorLevel)

cmd/kpod/wait.go

@@ -0,0 +1,62 @@
+package main
+
+import (
+	"fmt"
+	"os"
+
+	"github.com/kubernetes-incubator/cri-o/libkpod"
+	"github.com/pkg/errors"
+	"github.com/urfave/cli"
+)
+
+var (
+	waitDescription = `
+	kpod wait
+
+	Block until one or more containers stop and then print their exit codes
+`
+
+	waitCommand = cli.Command{
+		Name:        "wait",
+		Usage:       "Block on one or more containers",
+		Description: waitDescription,
+		Action:      waitCmd,
+		ArgsUsage:   "CONTAINER-NAME [CONTAINER-NAME ...]",
+	}
+)
+
+func waitCmd(c *cli.Context) error {
+	args := c.Args()
+	if len(args) < 1 {
+		return errors.Errorf("you must provide at least one container name or id")
+	}
+
+	config, err := getConfig(c)
+	if err != nil {
+		return errors.Wrapf(err, "could not get config")
+	}
+	server, err := libkpod.New(config)
+	if err != nil {
+		return errors.Wrapf(err, "could not get container server")
+	}
+	defer server.Shutdown()
+	err = server.Update()
+	if err != nil {
+		return errors.Wrapf(err, "could not update list of containers")
+	}
+
+	var lastError error
+	for _, container := range c.Args() {
+		returnCode, err := server.ContainerWait(container)
+		if err != nil {
+			if lastError != nil {
+				fmt.Fprintln(os.Stderr, lastError)
+			}
+			lastError = errors.Wrapf(err, "failed to wait for the container %v", container)
+		} else {
+			fmt.Println(returnCode)
+		}
+	}
+
+	return lastError
+}