ctr:Support deleting multiple tasks at a time

Signed-off-by: BoWen Yan <loneybw@gmail.com>

cmd/ctr/commands/tasks/delete.go

@@ -17,16 +17,20 @@
 package tasks
 
 import (
+	gocontext "context"
+
 	"github.com/containerd/containerd"
 	"github.com/containerd/containerd/cio"
 	"github.com/containerd/containerd/cmd/ctr/commands"
+	"github.com/containerd/containerd/log"
 	"github.com/urfave/cli"
 )
 
 var deleteCommand = cli.Command{
 	Name:      "delete",
-	Usage:     "[flags] delete a task",
-	ArgsUsage: "CONTAINER",
+	Usage:     "delete one or more tasks",
+	ArgsUsage: "CONTAINER [CONTAINER, ...]",
+	Aliases:   []string{"rm"},
 	Flags: []cli.Flag{
 		cli.BoolFlag{
 			Name:  "force, f",
@@ -47,19 +51,16 @@ var deleteCommand = cli.Command{
 			return err
 		}
 		defer cancel()
-		container, err := client.LoadContainer(ctx, context.Args().First())
-		if err != nil {
-			return err
-		}
-		task, err := container.Task(ctx, cio.Load)
-		if err != nil {
-			return err
-		}
 		var opts []containerd.ProcessDeleteOpts
 		if force {
 			opts = append(opts, containerd.WithProcessKill)
 		}
+		var exitErr error
 		if execID != "" {
+			task, err := loadTask(ctx, client, context.Args().First())
+			if err != nil {
+				return err
+			}
 			p, err := task.LoadProcess(ctx, execID, nil)
 			if err != nil {
 				return err
@@ -72,14 +73,40 @@ var deleteCommand = cli.Command{
 				return cli.NewExitError("", int(ec))
 			}
 		} else {
+			for _, target := range context.Args() {
+				task, err := loadTask(ctx, client, target)
+				if err != nil {
+					if exitErr == nil {
+						exitErr = err
+					}
+					log.G(ctx).WithError(err).Errorf("failed to load task from %v", target)
+					continue
+				}
 				status, err := task.Delete(ctx, opts...)
 				if err != nil {
-				return err
+					if exitErr == nil {
+						exitErr = err
+					}
+					log.G(ctx).WithError(err).Errorf("unable to delete %v", task.ID())
+					continue
 				}
 				if ec := status.ExitCode(); ec != 0 {
-				return cli.NewExitError("", int(ec))
+					log.G(ctx).Warnf("task %v exit with non-zero exit code %v", task.ID(), int(ec))
 				}
 			}
-		return nil
+		}
+		return exitErr
 	},
 }
+
+func loadTask(ctx gocontext.Context, client *containerd.Client, containerID string) (containerd.Task, error) {
+	container, err := client.LoadContainer(ctx, containerID)
+	if err != nil {
+		return nil, err
+	}
+	task, err := container.Task(ctx, cio.Load)
+	if err != nil {
+		return nil, err
+	}
+	return task, nil
+}