image/load: Add `--platform`

Signed-off-by: Paweł Gronowski <pawel.gronowski@docker.com>
Signed-off-by: Sebastiaan van Stijn <github@gone.nl>

cli/command/image/load.go

@@ -4,6 +4,7 @@ import (
 	"context"
 	"io"
 
+	"github.com/containerd/platforms"
 	"github.com/docker/cli/cli"
 	"github.com/docker/cli/cli/command"
 	"github.com/docker/cli/cli/command/completion"
@@ -17,6 +18,7 @@ import (
 type loadOptions struct {
 	input    string
 	quiet    bool
+	platform string
 }
 
 // NewLoadCommand creates a new `docker load` command
@@ -40,7 +42,10 @@ func NewLoadCommand(dockerCli command.Cli) *cobra.Command {
 
 	flags.StringVarP(&opts.input, "input", "i", "", "Read from tar archive file, instead of STDIN")
 	flags.BoolVarP(&opts.quiet, "quiet", "q", false, "Suppress the load output")
+	flags.StringVar(&opts.platform, "platform", "", `Load only the given platform variant. Formatted as "os[/arch[/variant]]" (e.g., "linux/amd64")`)
+	_ = flags.SetAnnotation("platform", "version", []string{"1.48"})
 
+	_ = cmd.RegisterFlagCompletionFunc("platform", completion.Platforms)
 	return cmd
 }
 
@@ -63,12 +68,20 @@ func runLoad(ctx context.Context, dockerCli command.Cli, opts loadOptions) error
 		return errors.Errorf("requested load from stdin, but stdin is empty")
 	}
 
-	var loadOpts image.LoadOptions
+	var options image.LoadOptions
 	if opts.quiet || !dockerCli.Out().IsTerminal() {
-		loadOpts.Quiet = true
+		options.Quiet = true
 	}
 
-	response, err := dockerCli.Client().ImageLoad(ctx, input, loadOpts)
+	if opts.platform != "" {
+		p, err := platforms.Parse(opts.platform)
+		if err != nil {
+			return errors.Wrap(err, "invalid platform")
+		}
+		options.Platform = &p
+	}
+
+	response, err := dockerCli.Client().ImageLoad(ctx, input, options)
 	if err != nil {
 		return err
 	}

cli/command/image/load_test.go

@@ -8,8 +8,10 @@ import (
 
 	"github.com/docker/cli/internal/test"
 	"github.com/docker/docker/api/types/image"
+	ocispec "github.com/opencontainers/image-spec/specs-go/v1"
 	"github.com/pkg/errors"
 	"gotest.tools/v3/assert"
+	is "gotest.tools/v3/assert/cmp"
 	"gotest.tools/v3/golden"
 )
 
@@ -40,6 +42,14 @@ func TestNewLoadCommandErrors(t *testing.T) {
 				return image.LoadResponse{}, errors.Errorf("something went wrong")
 			},
 		},
+		{
+			name:          "invalid platform",
+			args:          []string{"--platform", "<invalid>"},
+			expectedError: `invalid platform`,
+			imageLoadFunc: func(input io.Reader, options image.LoadOptions) (image.LoadResponse, error) {
+				return image.LoadResponse{}, nil
+			},
+		},
 	}
 	for _, tc := range testCases {
 		tc := tc
@@ -96,6 +106,14 @@ func TestNewLoadCommandSuccess(t *testing.T) {
 				return image.LoadResponse{Body: io.NopCloser(strings.NewReader("Success"))}, nil
 			},
 		},
+		{
+			name: "with platform",
+			args: []string{"--platform", "linux/amd64"},
+			imageLoadFunc: func(input io.Reader, options image.LoadOptions) (image.LoadResponse, error) {
+				assert.Check(t, is.DeepEqual(ocispec.Platform{OS: "linux", Architecture: "amd64"}, *options.Platform))
+				return image.LoadResponse{Body: io.NopCloser(strings.NewReader("Success"))}, nil
+			},
+		},
 	}
 	for _, tc := range testCases {
 		tc := tc

cli/command/image/testdata/load-command-success.with platform.golden

@@ -0,0 +1 @@
+Success

docs/reference/commandline/image_load.md

@@ -10,8 +10,9 @@ Load an image from a tar archive or STDIN
 ### Options
 
 | Name                                | Type     | Default | Description                                                                                    |
-|:------------------------------------|:---------|:--------|:---------------------------------------------|
+|:------------------------------------|:---------|:--------|:-----------------------------------------------------------------------------------------------|
 | [`-i`](#input), [`--input`](#input) | `string` |         | Read from tar archive file, instead of STDIN                                                   |
+| [`--platform`](#platform)           | `string` |         | Load only the given platform variant. Formatted as `os[/arch[/variant]]` (e.g., `linux/amd64`) |
 | `-q`, `--quiet`                     | `bool`   |         | Suppress the load output                                                                       |
 
 
@@ -58,3 +59,32 @@ fedora              20                  58394af37342        7 weeks ago
 fedora              heisenbug           58394af37342        7 weeks ago         385.5 MB
 fedora              latest              58394af37342        7 weeks ago         385.5 MB
 ```
+
+
+### <a name="platform"></a> Load a specific platform (--platform)
+
+The `--platform` option allows you to specify which platform variant of the
+image to load. By default, `docker load` loads all platform variants that
+are present in the archive. Use the `--platform` option to specify which
+platform variant of the image to load. An error is produced if the given
+platform is not present in the archive.
+
+The platform option takes the `os[/arch[/variant]]` format; for example,
+`linux/amd64` or `linux/arm64/v8`. Architecture and variant are optional,
+and default to the daemon's native architecture if omitted.
+
+The following example loads the `linux/amd64` variant of an `alpine` image
+from an archive that contains multiple platform variants.
+
+```console
+$ docker image load -i image.tar --platform=linux/amd64
+Loaded image: alpine:latest
+```
+
+The following example attempts to load a `linux/ppc64le` image from an
+archive, but the given platform is not present in the archive;
+
+```console
+$ docker image load -i image.tar --platform=linux/ppc64le
+requested platform (linux/ppc64le) not found: image might be filtered out
+```

docs/reference/commandline/load.md

@@ -10,8 +10,9 @@ Load an image from a tar archive or STDIN
 ### Options
 
 | Name            | Type     | Default | Description                                                                                    |
-|:----------------|:---------|:--------|:---------------------------------------------|
+|:----------------|:---------|:--------|:-----------------------------------------------------------------------------------------------|
 | `-i`, `--input` | `string` |         | Read from tar archive file, instead of STDIN                                                   |
+| `--platform`    | `string` |         | Load only the given platform variant. Formatted as `os[/arch[/variant]]` (e.g., `linux/amd64`) |
 | `-q`, `--quiet` | `bool`   |         | Suppress the load output                                                                       |