image: Add convert command

Signed-off-by: Paweł Gronowski <pawel.gronowski@docker.com>

Author: vvoland

cli/command/image/cmd.go

@@ -27,6 +27,7 @@ func NewImageCommand(dockerCli command.Cli) *cobra.Command {
 		newRemoveCommand(dockerCli),
 		newInspectCommand(dockerCli),
 		NewPruneCommand(dockerCli),
+		NewConvertCommand(dockerCli),
 	)
 	return cmd
 }

cli/command/image/convert.go

@@ -0,0 +1,83 @@
+package image
+
+import (
+	"context"
+	"fmt"
+
+	"github.com/containerd/platforms"
+	"github.com/distribution/reference"
+	"github.com/docker/cli/cli"
+	"github.com/docker/cli/cli/command"
+	imagetypes "github.com/docker/docker/api/types/image"
+	"github.com/spf13/cobra"
+)
+
+type convertArgs struct {
+	Src                    string
+	Dst                    []string
+	Platforms              []string
+	NoAttestations         bool
+	OnlyAvailablePlatforms bool
+}
+
+func NewConvertCommand(dockerCli command.Cli) *cobra.Command {
+	var args convertArgs
+
+	cmd := &cobra.Command{
+		Use:   "convert [OPTIONS]",
+		Short: "Convert multi-platform images",
+		Args:  cli.ExactArgs(0),
+		RunE: func(cmd *cobra.Command, _ []string) error {
+			return runConvert(cmd.Context(), dockerCli, args)
+		},
+		Aliases: []string{"convert"},
+		Annotations: map[string]string{
+			"aliases": "docker image convert, docker convert",
+		},
+	}
+
+	flags := cmd.Flags()
+	flags.StringArrayVar(&args.Platforms, "platforms", nil, "Include only the specified platforms in the destination image")
+	flags.BoolVar(&args.NoAttestations, "no-attestations", false, "Do not include image attestations")
+	flags.BoolVar(&args.OnlyAvailablePlatforms, "available", false, "Only include platforms locally available to the daemon")
+	flags.StringArrayVar(&args.Dst, "to", nil, "Target image references")
+	flags.StringVar(&args.Src, "from", "", "Source image reference")
+
+	return cmd
+}
+
+func runConvert(ctx context.Context, dockerCLI command.Cli, args convertArgs) error {
+	if len(args.Dst) == 0 {
+		return fmt.Errorf("No destination image specified")
+	}
+	if args.Src == "" {
+		return fmt.Errorf("No source image specified")
+	}
+
+	var dstRefs []reference.NamedTagged
+	for _, dst := range args.Dst {
+		dstRef, err := reference.ParseNormalizedNamed(dst)
+		if err != nil {
+			return fmt.Errorf("invalid destination image reference: %s: %w", dst, err)
+		}
+
+		dstRef = reference.TagNameOnly(dstRef)
+		dstRefTagged := dstRef.(reference.NamedTagged)
+		dstRefs = append(dstRefs, dstRefTagged)
+	}
+
+	opts := imagetypes.ConvertOptions{
+		NoAttestations:         args.NoAttestations,
+		OnlyAvailablePlatforms: args.OnlyAvailablePlatforms,
+	}
+
+	for _, platform := range args.Platforms {
+		p, err := platforms.Parse(platform)
+		if err != nil {
+			return err
+		}
+		opts.Platforms = append(opts.Platforms, p)
+	}
+
+	return dockerCLI.Client().ImageConvert(ctx, args.Src, dstRefs, opts)
+}