Add option to pull images quietly

Add `--quiet` to the `docker image pull` subcommand that will not pull
the image quietly.

```
$ docker pull -q golang
Using default tag: latest
```

Signed-off-by: Vincent Demeester <vincent@sbr.pm>

cli/command/image/pull.go

@@ -18,6 +18,7 @@ type PullOptions struct {
 	remote    string
 	all       bool
 	platform  string
+	quiet     bool
 	untrusted bool
 }
 
@@ -38,6 +39,7 @@ func NewPullCommand(dockerCli command.Cli) *cobra.Command {
 	flags := cmd.Flags()
 
 	flags.BoolVarP(&opts.all, "all-tags", "a", false, "Download all tagged images in the repository")
+	flags.BoolVarP(&opts.quiet, "quiet", "q", false, "Suppress verbose output")
 
 	command.AddPlatformFlag(flags, &opts.platform)
 	command.AddTrustVerificationFlags(flags, &opts.untrusted, dockerCli.ContentTrustEnabled())
@@ -55,7 +57,7 @@ func RunPull(cli command.Cli, opts PullOptions) error {
 		return errors.New("tag can't be used with --all-tags/-a")
 	case !opts.all && reference.IsNameOnly(distributionRef):
 		distributionRef = reference.TagNameOnly(distributionRef)
-		if tagged, ok := distributionRef.(reference.Tagged); ok {
+		if tagged, ok := distributionRef.(reference.Tagged); ok && !opts.quiet {
 			fmt.Fprintf(cli.Out(), "Using default tag: %s\n", tagged.Tag())
 		}
 	}
@@ -69,9 +71,9 @@ func RunPull(cli command.Cli, opts PullOptions) error {
 	// Check if reference has a digest
 	_, isCanonical := distributionRef.(reference.Canonical)
 	if !opts.untrusted && !isCanonical {
-		err = trustedPull(ctx, cli, imgRefAndAuth, opts.platform)
+		err = trustedPull(ctx, cli, imgRefAndAuth, opts)
 	} else {
-		err = imagePullPrivileged(ctx, cli, imgRefAndAuth, opts.all, opts.platform)
+		err = imagePullPrivileged(ctx, cli, imgRefAndAuth, opts)
 	}
 	if err != nil {
 		if strings.Contains(err.Error(), "when fetching 'plugin'") {
@@ -79,5 +81,6 @@ func RunPull(cli command.Cli, opts PullOptions) error {
 		}
 		return err
 	}
+	fmt.Fprintln(cli.Out(), imgRefAndAuth.Reference().String())
 	return nil
 }

cli/command/image/pull_test.go

@@ -50,6 +50,7 @@ func TestNewPullCommandSuccess(t *testing.T) {
 	testCases := []struct {
 		name        string
 		args        []string
+		flags       map[string]string
 		expectedTag string
 	}{
 		{
@@ -62,6 +63,14 @@ func TestNewPullCommandSuccess(t *testing.T) {
 			args:        []string{"image"},
 			expectedTag: "image:latest",
 		},
+		{
+			name: "simple-quiet",
+			args: []string{"image"},
+			flags: map[string]string{
+				"quiet": "true",
+			},
+			expectedTag: "image:latest",
+		},
 	}
 	for _, tc := range testCases {
 		cli := test.NewFakeCli(&fakeClient{

cli/command/image/testdata/pull-command-success.simple-no-tag.golden

@@ -1 +1,2 @@
 Using default tag: latest
+docker.io/library/image:latest

cli/command/image/testdata/pull-command-success.simple-quiet.golden

@@ -0,0 +1,2 @@
+Using default tag: latest
+docker.io/library/image:latest

cli/command/image/testdata/pull-command-success.simple.golden

@@ -0,0 +1 @@
+docker.io/library/image:tag

cli/command/image/trust.go

@@ -6,6 +6,7 @@ import (
 	"encoding/json"
 	"fmt"
 	"io"
+	"io/ioutil"
 	"sort"
 
 	"github.com/docker/cli/cli/command"
@@ -180,7 +181,7 @@ func imagePushPrivileged(ctx context.Context, cli command.Cli, authConfig types.
 }
 
 // trustedPull handles content trust pulling of an image
-func trustedPull(ctx context.Context, cli command.Cli, imgRefAndAuth trust.ImageRefAndAuth, platform string) error {
+func trustedPull(ctx context.Context, cli command.Cli, imgRefAndAuth trust.ImageRefAndAuth, opts PullOptions) error {
 	refs, err := getTrustedPullTargets(cli, imgRefAndAuth)
 	if err != nil {
 		return err
@@ -202,7 +203,12 @@ func trustedPull(ctx context.Context, cli command.Cli, imgRefAndAuth trust.Image
 		if err != nil {
 			return err
 		}
-		if err := imagePullPrivileged(ctx, cli, updatedImgRefAndAuth, false, platform); err != nil {
+		if err := imagePullPrivileged(ctx, cli, updatedImgRefAndAuth, PullOptions{
+			all:      false,
+			platform: opts.platform,
+			quiet:    opts.quiet,
+			remote:   opts.remote,
+		}); err != nil {
 			return err
 		}
 
@@ -268,7 +274,7 @@ func getTrustedPullTargets(cli command.Cli, imgRefAndAuth trust.ImageRefAndAuth)
 }
 
 // imagePullPrivileged pulls the image and displays it to the output
-func imagePullPrivileged(ctx context.Context, cli command.Cli, imgRefAndAuth trust.ImageRefAndAuth, all bool, platform string) error {
+func imagePullPrivileged(ctx context.Context, cli command.Cli, imgRefAndAuth trust.ImageRefAndAuth, opts PullOptions) error {
 	ref := reference.FamiliarString(imgRefAndAuth.Reference())
 
 	encodedAuth, err := command.EncodeAuthToBase64(*imgRefAndAuth.AuthConfig())
@@ -279,8 +285,8 @@ func imagePullPrivileged(ctx context.Context, cli command.Cli, imgRefAndAuth tru
 	options := types.ImagePullOptions{
 		RegistryAuth:  encodedAuth,
 		PrivilegeFunc: requestPrivilege,
-		All:           all,
-		Platform:      platform,
+		All:           opts.all,
+		Platform:      opts.platform,
 	}
 	responseBody, err := cli.Client().ImagePull(ctx, ref, options)
 	if err != nil {
@@ -288,7 +294,11 @@ func imagePullPrivileged(ctx context.Context, cli command.Cli, imgRefAndAuth tru
 	}
 	defer responseBody.Close()
 
-	return jsonmessage.DisplayJSONMessagesToStream(responseBody, cli.Out(), nil)
+	out := cli.Out()
+	if opts.quiet {
+		out = command.NewOutStream(ioutil.Discard)
+	}
+	return jsonmessage.DisplayJSONMessagesToStream(responseBody, out, nil)
 }
 
 // TrustedReference returns the canonical trusted reference for an image reference

docs/reference/commandline/pull.md

@@ -24,6 +24,7 @@ Options:
   -a, --all-tags                Download all tagged images in the repository
       --disable-content-trust   Skip image verification (default true)
       --help                    Print usage
+  -q, --quiet                   Suppress verbose output
 ```
 
 ## Description

e2e/image/pull_test.go

@@ -5,6 +5,8 @@ import (
 
 	"github.com/docker/cli/e2e/internal/fixtures"
 	"github.com/docker/cli/internal/test/environment"
+	"gotest.tools/assert"
+	is "gotest.tools/assert/cmp"
 	"gotest.tools/golden"
 	"gotest.tools/icmd"
 	"gotest.tools/skip"
@@ -32,6 +34,13 @@ func TestPullWithContentTrust(t *testing.T) {
 	golden.Assert(t, result.Stdout(), "pull-with-content-trust.golden")
 }
 
+func TestPullQuiet(t *testing.T) {
+	result := icmd.RunCommand("docker", "pull", "--quiet", fixtures.AlpineImage)
+	result.Assert(t, icmd.Success)
+	assert.Check(t, is.Equal(result.Stdout(), "registry:5000/alpine:3.6\n"))
+	assert.Check(t, is.Equal(result.Stderr(), ""))
+}
+
 func TestPullWithContentTrustUsesCacheWhenNotaryUnavailable(t *testing.T) {
 	skip.If(t, environment.RemoteDaemon())
 

e2e/image/testdata/pull-with-content-trust.golden

@@ -2,3 +2,4 @@ Pull (1 of 1): registry:5000/trust-pull:latest@sha256:641b95ddb2ea9dc2af1a0113b6
 sha256:641b95ddb2ea9dc2af1a0113b6b348ebc20872ba615204fbe12148e98fd6f23d: Pulling from trust-pull
 Digest: sha256:641b95ddb2ea9dc2af1a0113b6b348ebc20872ba615204fbe12148e98fd6f23d
 Status: Downloaded newer image for registry:5000/trust-pull@sha256:641b95ddb2ea9dc2af1a0113b6b348ebc20872ba615204fbe12148e98fd6f23d
+registry:5000/trust-pull:latest