Add --force flag to runc delete

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

delete.go

@@ -13,6 +13,18 @@ import (
 	"github.com/urfave/cli"
 )
 
+func killContainer(container libcontainer.Container) error {
+	container.Signal(syscall.SIGKILL)
+	for i := 0; i < 100; i++ {
+		time.Sleep(100 * time.Millisecond)
+		if err := container.Signal(syscall.Signal(0)); err != nil {
+			destroy(container)
+			return nil
+		}
+	}
+	return fmt.Errorf("container init still running")
+}
+
 var deleteCommand = cli.Command{
 	Name:  "delete",
 	Usage: "delete any resources held by the container often used with detached containers",
@@ -23,9 +35,15 @@ Where "<container-id>" is the name for the instance of the container.
 EXAMPLE:
 For example, if the container id is "ubuntu01" and runc list currently shows the
 status of "ubuntu01" as "stopped" the following will delete resources held for
-"ubuntu01" removing "ubuntu01" from the runc list of containers:  
-	 
+"ubuntu01" removing "ubuntu01" from the runc list of containers:
+
        # runc delete ubuntu01`,
+	Flags: []cli.Flag{
+		cli.BoolFlag{
+			Name:  "force, f",
+			Usage: "Forcibly kills the container if it is still running",
+		},
+	},
 	Action: func(context *cli.Context) error {
 		container, err := getContainer(context)
 		if err != nil {
@@ -47,16 +65,11 @@ status of "ubuntu01" as "stopped" the following will delete resources held for
 		case libcontainer.Stopped:
 			destroy(container)
 		case libcontainer.Created:
-			container.Signal(syscall.SIGKILL)
-			for i := 0; i < 100; i++ {
-				time.Sleep(100 * time.Millisecond)
-				if err := container.Signal(syscall.Signal(0)); err != nil {
-					destroy(container)
-					return nil
-				}
-			}
-			return fmt.Errorf("container init still running")
+			return killContainer(container)
 		default:
+			if context.Bool("force") {
+				return killContainer(container)
+			}
 			return fmt.Errorf("cannot delete container that is not stopped: %s", s)
 		}
 		return nil