Use spf13/cobra for docker diff

This fix is part of the effort to convert commands to spf13/cobra #23211.

Thif fix coverted command `docker diff` to use spf13/cobra

Signed-off-by: Yong Tang <yong.tang.github@outlook.com>

api/client/commands.go

@@ -7,7 +7,6 @@ func (cli *DockerCli) Command(name string) func(...string) error {
 		"build":              cli.CmdBuild,
 		"commit":             cli.CmdCommit,
 		"cp":                 cli.CmdCp,
-		"diff":               cli.CmdDiff,
 		"events":             cli.CmdEvents,
 		"exec":               cli.CmdExec,
 		"history":            cli.CmdHistory,

api/client/container/diff.go

@@ -0,0 +1,58 @@
+package container
+
+import (
+	"fmt"
+
+	"golang.org/x/net/context"
+
+	"github.com/docker/docker/api/client"
+	"github.com/docker/docker/cli"
+	"github.com/docker/docker/pkg/archive"
+	"github.com/spf13/cobra"
+)
+
+type diffOptions struct {
+	container string
+}
+
+// NewDiffCommand creats a new cobra.Command for `docker diff`
+func NewDiffCommand(dockerCli *client.DockerCli) *cobra.Command {
+	var opts diffOptions
+
+	cmd := &cobra.Command{
+		Use:   "diff CONTAINER",
+		Short: "Inspect changes on a container's filesystem",
+		Args:  cli.ExactArgs(1),
+		RunE: func(cmd *cobra.Command, args []string) error {
+			opts.container = args[0]
+			return runDiff(dockerCli, &opts)
+		},
+	}
+	cmd.SetFlagErrorFunc(flagErrorFunc)
+
+	return cmd
+}
+
+func runDiff(dockerCli *client.DockerCli, opts *diffOptions) error {
+	ctx := context.Background()
+
+	changes, err := dockerCli.Client().ContainerDiff(ctx, opts.container)
+	if err != nil {
+		return err
+	}
+
+	for _, change := range changes {
+		var kind string
+		switch change.Kind {
+		case archive.ChangeModify:
+			kind = "C"
+		case archive.ChangeAdd:
+			kind = "A"
+		case archive.ChangeDelete:
+			kind = "D"
+		}
+		fmt.Fprintf(dockerCli.Out(), "%s %s\n", kind, change.Path)
+	}
+
+	return nil
+}

api/client/diff.go

@@ -1,49 +0,0 @@
-package client
-
-import (
-	"fmt"
-
-	"golang.org/x/net/context"
-
-	Cli "github.com/docker/docker/cli"
-	"github.com/docker/docker/pkg/archive"
-	flag "github.com/docker/docker/pkg/mflag"
-)
-
-// CmdDiff shows changes on a container's filesystem.
-//
-// Each changed file is printed on a separate line, prefixed with a single
-// character that indicates the status of the file: C (modified), A (added),
-// or D (deleted).
-//
-// Usage: docker diff CONTAINER
-func (cli *DockerCli) CmdDiff(args ...string) error {
-	cmd := Cli.Subcmd("diff", []string{"CONTAINER"}, Cli.DockerCommands["diff"].Description, true)
-	cmd.Require(flag.Exact, 1)
-
-	cmd.ParseFlags(args, true)
-
-	if cmd.Arg(0) == "" {
-		return fmt.Errorf("Container name cannot be empty")
-	}
-
-	changes, err := cli.client.ContainerDiff(context.Background(), cmd.Arg(0))
-	if err != nil {
-		return err
-	}
-
-	for _, change := range changes {
-		var kind string
-		switch change.Kind {
-		case archive.ChangeModify:
-			kind = "C"
-		case archive.ChangeAdd:
-			kind = "A"
-		case archive.ChangeDelete:
-			kind = "D"
-		}
-		fmt.Fprintf(cli.out, "%s %s\n", kind, change.Path)
-	}
-
-	return nil
-}

cli/cobraadaptor/adaptor.go

@@ -34,6 +34,7 @@ func NewCobraAdaptor(clientFlags *cliflags.ClientFlags) CobraAdaptor {
 	rootCmd.SetOutput(stdout)
 	rootCmd.AddCommand(
 		container.NewCreateCommand(dockerCli),
+		container.NewDiffCommand(dockerCli),
 		container.NewExportCommand(dockerCli),
 		container.NewRunCommand(dockerCli),
 		container.NewStopCommand(dockerCli),

cli/usage.go

@@ -12,7 +12,6 @@ var DockerCommandUsage = []Command{
 	{"build", "Build an image from a Dockerfile"},
 	{"commit", "Create a new image from a container's changes"},
 	{"cp", "Copy files/folders between a container and the local filesystem"},
-	{"diff", "Inspect changes on a container's filesystem"},
 	{"events", "Get real time events from the server"},
 	{"exec", "Run a command in a running container"},
 	{"history", "Show the history of an image"},

integration-cli/docker_cli_diff_test.go

@@ -83,5 +83,5 @@ func (s *DockerSuite) TestDiffEnsureDefaultDevs(c *check.C) {
 func (s *DockerSuite) TestDiffEmptyArgClientError(c *check.C) {
 	out, _, err := dockerCmdWithError("diff", "")
 	c.Assert(err, checker.NotNil)
-	c.Assert(strings.TrimSpace(out), checker.Equals, "Container name cannot be empty")
+	c.Assert(strings.TrimSpace(out), checker.Contains, "\"docker diff\" requires exactly 1 argument(s).")
 }