add commit compression type support

Signed-off-by: rongfu.leng <rongfu.leng@daocloud.io>

Author: lengrongfu

cmd/nerdctl/container/container_commit.go

@@ -40,6 +40,7 @@ func CommitCommand() *cobra.Command {
 	cmd.Flags().StringP("message", "m", "", "Commit message")
 	cmd.Flags().StringArrayP("change", "c", nil, "Apply Dockerfile instruction to the created image (supported directives: [CMD, ENTRYPOINT])")
 	cmd.Flags().BoolP("pause", "p", true, "Pause container during commit")
+	cmd.Flags().StringP("compression", "", "", "commit compression algorithm,value is zstd or gzip, default is gzip")
 	return cmd
 }
 
@@ -66,13 +67,18 @@ func commitOptions(cmd *cobra.Command) (types.ContainerCommitOptions, error) {
 		return types.ContainerCommitOptions{}, err
 	}
 
+	com, err := cmd.Flags().GetString("compression")
+	if err != nil {
+		return types.ContainerCommitOptions{}, err
+	}
 	return types.ContainerCommitOptions{
-		Stdout:   cmd.OutOrStdout(),
-		GOptions: globalOptions,
-		Author:   author,
-		Message:  message,
-		Pause:    pause,
-		Change:   change,
+		Stdout:      cmd.OutOrStdout(),
+		GOptions:    globalOptions,
+		Author:      author,
+		Message:     message,
+		Pause:       pause,
+		Change:      change,
+		Compression: com,
 	}, nil
 
 }

pkg/api/types/container_types.go

@@ -371,6 +371,8 @@ type ContainerCommitOptions struct {
 	Change []string
 	// Pause container during commit
 	Pause bool
+	// Compression is set commit compression algorithm
+	Compression string
 }
 
 // ContainerDiffOptions specifies options for `nerdctl (container) diff`.

pkg/cmd/container/commit.go

@@ -44,11 +44,12 @@ func Commit(ctx context.Context, client *containerd.Client, rawRef string, req s
 	}
 
 	opts := &commit.Opts{
-		Author:  options.Author,
-		Message: options.Message,
-		Ref:     parsedReference.String(),
-		Pause:   options.Pause,
-		Changes: changes,
+		Author:      options.Author,
+		Message:     options.Message,
+		Ref:         parsedReference.String(),
+		Pause:       options.Pause,
+		Changes:     changes,
+		Compression: options.Compression,
 	}
 
 	walker := &containerwalker.ContainerWalker{

pkg/imgutil/commit/commit.go

@@ -57,11 +57,12 @@ type Changes struct {
 }
 
 type Opts struct {
-	Author  string
-	Message string
-	Ref     string
-	Pause   bool
-	Changes Changes
+	Author      string
+	Message     string
+	Ref         string
+	Pause       bool
+	Changes     Changes
+	Compression string
 }
 
 var (
@@ -176,7 +177,7 @@ func Commit(ctx context.Context, client *containerd.Client, container containerd
 	// Sync filesystem to make sure that all the data writes in container could be persisted to disk.
 	Sync()
 
-	diffLayerDesc, diffID, err := createDiff(ctx, id, sn, client.ContentStore(), differ)
+	diffLayerDesc, diffID, err := createDiff(ctx, id, sn, client.ContentStore(), differ, opts.Compression)
 	if err != nil {
 		return emptyDigest, fmt.Errorf("failed to export layer: %w", err)
 	}
@@ -356,8 +357,14 @@ func writeContentsForImage(ctx context.Context, snName string, baseImg container
 }
 
 // createDiff creates a layer diff into containerd's content store.
-func createDiff(ctx context.Context, name string, sn snapshots.Snapshotter, cs content.Store, comparer diff.Comparer) (ocispec.Descriptor, digest.Digest, error) {
-	newDesc, err := rootfs.CreateDiff(ctx, name, sn, comparer)
+func createDiff(ctx context.Context, name string, sn snapshots.Snapshotter, cs content.Store, comparer diff.Comparer, compression string) (ocispec.Descriptor, digest.Digest, error) {
+	opts := make([]diff.Opt, 0)
+	mediaType := images.MediaTypeDockerSchema2LayerGzip
+	if compression == "zstd" {
+		opts = append(opts, diff.WithMediaType(ocispec.MediaTypeImageLayerZstd))
+		mediaType = images.MediaTypeDockerSchema2LayerZstd
+	}
+	newDesc, err := rootfs.CreateDiff(ctx, name, sn, comparer, opts...)
 	if err != nil {
 		return ocispec.Descriptor{}, digest.Digest(""), err
 	}
@@ -378,7 +385,7 @@ func createDiff(ctx context.Context, name string, sn snapshots.Snapshotter, cs c
 	}
 
 	return ocispec.Descriptor{
-		MediaType: images.MediaTypeDockerSchema2LayerGzip,
+		MediaType: mediaType,
 		Digest:    newDesc.Digest,
 		Size:      info.Size,
 	}, diffID, nil