Use Args in cobra.Command to validate args.

Also re-use context.

Signed-off-by: Daniel Nephin <dnephin@docker.com>

api/client/volume/cmd.go

@@ -14,13 +14,9 @@ func NewVolumeCommand(dockerCli *client.DockerCli) *cobra.Command {
 	cmd := &cobra.Command{
 		Use:   "volume",
 		Short: "Manage Docker volumes",
-		// TODO: remove once cobra is patched to handle this
+		Args:  cli.NoArgs,
-		RunE: func(cmd *cobra.Command, args []string) error {
+		Run: func(cmd *cobra.Command, args []string) {
-			fmt.Fprintf(dockerCli.Err(), "\n%s", cmd.UsageString())
+			fmt.Fprintf(dockerCli.Err(), "\n"+cmd.UsageString())
-			if len(args) > 0 {
-				return cli.StatusError{StatusCode: 1}
-			}
-			return nil
 		},
 	}
 	cmd.AddCommand(

api/client/volume/create.go

@@ -28,11 +28,8 @@ func newCreateCommand(dockerCli *client.DockerCli) *cobra.Command {
 	cmd := &cobra.Command{
 		Use:   "create",
 		Short: "Create a volume",
+		Args:  cli.NoArgs,
 		RunE: func(cmd *cobra.Command, args []string) error {
-			// TODO: remove once cobra is patched to handle this
-			if err := cli.AcceptsNoArgs(args, cmd); err != nil {
-				return err
-			}
 			return runCreate(dockerCli, opts)
 		},
 	}

api/client/volume/inspect.go

@@ -20,10 +20,8 @@ func newInspectCommand(dockerCli *client.DockerCli) *cobra.Command {
 	cmd := &cobra.Command{
 		Use:   "inspect [OPTIONS] VOLUME [VOLUME...]",
 		Short: "Return low-level information on a volume",
+		Args:  cli.RequiresMinArgs(1),
 		RunE: func(cmd *cobra.Command, args []string) error {
-			if err := cli.MinRequiredArgs(args, 1, cmd); err != nil {
-				return err
-			}
 			opts.names = args
 			return runInspect(dockerCli, opts)
 		},

api/client/volume/list.go

@@ -34,11 +34,8 @@ func newListCommand(dockerCli *client.DockerCli) *cobra.Command {
 		Use:     "ls",
 		Aliases: []string{"list"},
 		Short:   "List volumes",
+		Args:    cli.NoArgs,
 		RunE: func(cmd *cobra.Command, args []string) error {
-			// TODO: remove once cobra is patched to handle this
-			if err := cli.AcceptsNoArgs(args, cmd); err != nil {
-				return err
-			}
 			return runList(dockerCli, opts)
 		},
 	}

api/client/volume/remove.go

@@ -15,10 +15,8 @@ func newRemoveCommand(dockerCli *client.DockerCli) *cobra.Command {
 		Use:     "rm VOLUME [VOLUME]...",
 		Aliases: []string{"remove"},
 		Short:   "Remove a volume",
+		Args:    cli.RequiresMinArgs(1),
 		RunE: func(cmd *cobra.Command, args []string) error {
-			if err := cli.MinRequiredArgs(args, 1, cmd); err != nil {
-				return err
-			}
 			return runRemove(dockerCli, args)
 		},
 	}
@@ -26,10 +24,11 @@ func newRemoveCommand(dockerCli *client.DockerCli) *cobra.Command {
 
 func runRemove(dockerCli *client.DockerCli, volumes []string) error {
 	client := dockerCli.Client()
-	var status = 0
+	ctx := context.Background()
+	status := 0
 
 	for _, name := range volumes {
-		if err := client.VolumeRemove(context.Background(), name); err != nil {
+		if err := client.VolumeRemove(ctx, name); err != nil {
 			fmt.Fprintf(dockerCli.Err(), "%s\n", err)
 			status = 1
 			continue

cli/required.go

@@ -2,30 +2,19 @@ package cli
 
 import (
 	"fmt"
+	"strings"
 
 	"github.com/spf13/cobra"
 )
 
-// MinRequiredArgs checks if the minimum number of args exists, and returns an
+// NoArgs validate args and returns an error if there are any args
-// error if they do not.
+func NoArgs(cmd *cobra.Command, args []string) error {
-func MinRequiredArgs(args []string, min int, cmd *cobra.Command) error {
+	if len(args) == 0 {
-	if len(args) >= min {
 		return nil
 	}
 
-	return fmt.Errorf(
+	if cmd.HasSubCommands() {
-		"\"%s\" requires at least %d argument(s).\n\nUsage:  %s\n\n%s",
+		return fmt.Errorf("\n" + strings.TrimRight(cmd.UsageString(), "\n"))
-		cmd.CommandPath(),
-		min,
-		cmd.UseLine(),
-		cmd.Short,
-	)
-}
-
-// AcceptsNoArgs returns an error message if there are args
-func AcceptsNoArgs(args []string, cmd *cobra.Command) error {
-	if len(args) == 0 {
-		return nil
 	}
 
 	return fmt.Errorf(
@@ -35,3 +24,19 @@ func AcceptsNoArgs(args []string, cmd *cobra.Command) error {
 		cmd.Short,
 	)
 }
+
+// RequiresMinArgs returns an error if there is not at least min args
+func RequiresMinArgs(min int) cobra.PositionalArgs {
+	return func(cmd *cobra.Command, args []string) error {
+		if len(args) >= min {
+			return nil
+		}
+		return fmt.Errorf(
+			"\"%s\" requires at least %d argument(s).\n\nUsage:  %s\n\n%s",
+			cmd.CommandPath(),
+			min,
+			cmd.UseLine(),
+			cmd.Short,
+		)
+	}
+}

integration-cli/docker_cli_help_test.go

@@ -335,7 +335,7 @@ func testCommand(cmd string, newEnvs []string, scanForHome bool, home string) er
 			return fmt.Errorf("Should not have full usage on %q\n", args)
 		}
 		if strings.HasSuffix(stderr, "\n\n") {
-			return fmt.Errorf("Should not have a blank line on %q\n", args)
+			return fmt.Errorf("Should not have a blank line on %q\n%v", args, stderr)
 		}
 	}