Merge pull request #11068 from k8s-infra-cherrypick-robot/cherry-pick-11062-to-release/2.0

[release/2.0] Update differ to handle zstd media types

pkg/archive/compression/compression.go

@@ -45,6 +45,8 @@ const (
 	Gzip
 	// Zstd is zstd compression algorithm.
 	Zstd
+	// Unknown is used when a plugin handles the algorithm.
+	Unknown
 )
 
 const (
@@ -257,6 +259,8 @@ func (compression *Compression) Extension() string {
 		return "gz"
 	case Zstd:
 		return "zst"
+	case Unknown:
+		return "unknown"
 	}
 	return ""
 }

plugins/diff/walking/differ.go

@@ -25,6 +25,11 @@ import (
 	"io"
 	"time"
 
+	"github.com/containerd/errdefs"
+	"github.com/containerd/log"
+	digest "github.com/opencontainers/go-digest"
+	ocispec "github.com/opencontainers/image-spec/specs-go/v1"
+
 	"github.com/containerd/containerd/v2/core/content"
 	"github.com/containerd/containerd/v2/core/diff"
 	"github.com/containerd/containerd/v2/core/mount"
@@ -32,10 +37,6 @@ import (
 	"github.com/containerd/containerd/v2/pkg/archive/compression"
 	"github.com/containerd/containerd/v2/pkg/epoch"
 	"github.com/containerd/containerd/v2/pkg/labels"
-	"github.com/containerd/errdefs"
-	"github.com/containerd/log"
-	digest "github.com/opencontainers/go-digest"
-	ocispec "github.com/opencontainers/image-spec/specs-go/v1"
 )
 
 type walkingDiff struct {
@@ -74,12 +75,12 @@ func (s *walkingDiff) Compare(ctx context.Context, lower, upper []mount.Mount, o
 		writeDiffOpts = append(writeDiffOpts, archive.WithSourceDateEpoch(config.SourceDateEpoch))
 	}
 
-	var isCompressed bool
+	compressionType := compression.Uncompressed
 	if config.Compressor != nil {
 		if config.MediaType == "" {
 			return emptyDesc, errors.New("media type must be explicitly specified when using custom compressor")
 		}
-		isCompressed = true
+		compressionType = compression.Unknown
 	} else {
 		if config.MediaType == "" {
 			config.MediaType = ocispec.MediaTypeImageLayerGzip
@@ -88,7 +89,9 @@ func (s *walkingDiff) Compare(ctx context.Context, lower, upper []mount.Mount, o
 		switch config.MediaType {
 		case ocispec.MediaTypeImageLayer:
 		case ocispec.MediaTypeImageLayerGzip:
-			isCompressed = true
+			compressionType = compression.Gzip
+		case ocispec.MediaTypeImageLayerZstd:
+			compressionType = compression.Zstd
 		default:
 			return emptyDesc, fmt.Errorf("unsupported diff media type: %v: %w", config.MediaType, errdefs.ErrNotImplemented)
 		}
@@ -131,7 +134,7 @@ func (s *walkingDiff) Compare(ctx context.Context, lower, upper []mount.Mount, o
 				}
 			}
 
-			if isCompressed {
+			if compressionType != compression.Uncompressed {
 				dgstr := digest.SHA256.Digester()
 				var compressed io.WriteCloser
 				if config.Compressor != nil {
@@ -140,7 +143,7 @@ func (s *walkingDiff) Compare(ctx context.Context, lower, upper []mount.Mount, o
 						return fmt.Errorf("failed to get compressed stream: %w", errOpen)
 					}
 				} else {
-					compressed, errOpen = compression.CompressStream(cw, compression.Gzip)
+					compressed, errOpen = compression.CompressStream(cw, compressionType)
 					if errOpen != nil {
 						return fmt.Errorf("failed to get compressed stream: %w", errOpen)
 					}

plugins/diff/windows/windows.go

@@ -28,6 +28,14 @@ import (
 	"time"
 
 	"github.com/Microsoft/go-winio"
+	"github.com/containerd/errdefs"
+	"github.com/containerd/log"
+	"github.com/containerd/platforms"
+	"github.com/containerd/plugin"
+	"github.com/containerd/plugin/registry"
+	"github.com/opencontainers/go-digest"
+	ocispec "github.com/opencontainers/image-spec/specs-go/v1"
+
 	"github.com/containerd/containerd/v2/core/content"
 	"github.com/containerd/containerd/v2/core/diff"
 	"github.com/containerd/containerd/v2/core/metadata"
@@ -37,13 +45,6 @@ import (
 	"github.com/containerd/containerd/v2/pkg/epoch"
 	"github.com/containerd/containerd/v2/pkg/labels"
 	"github.com/containerd/containerd/v2/plugins"
-	"github.com/containerd/errdefs"
-	"github.com/containerd/log"
-	"github.com/containerd/platforms"
-	"github.com/containerd/plugin"
-	"github.com/containerd/plugin/registry"
-	"github.com/opencontainers/go-digest"
-	ocispec "github.com/opencontainers/image-spec/specs-go/v1"
 )
 
 func init() {
@@ -197,11 +198,13 @@ func (s windowsDiff) Compare(ctx context.Context, lower, upper []mount.Mount, op
 		config.MediaType = ocispec.MediaTypeImageLayerGzip
 	}
 
-	var isCompressed bool
+	compressionType := compression.Uncompressed
 	switch config.MediaType {
 	case ocispec.MediaTypeImageLayer:
 	case ocispec.MediaTypeImageLayerGzip:
-		isCompressed = true
+		compressionType = compression.Gzip
+	case ocispec.MediaTypeImageLayerZstd:
+		compressionType = compression.Zstd
 	default:
 		return emptyDesc, fmt.Errorf("unsupported diff media type: %v: %w", config.MediaType, errdefs.ErrNotImplemented)
 	}
@@ -245,10 +248,10 @@ func (s windowsDiff) Compare(ctx context.Context, lower, upper []mount.Mount, op
 		return emptyDesc, err
 	}
 
-	if isCompressed {
+	if compressionType != compression.Uncompressed {
 		dgstr := digest.SHA256.Digester()
 		var compressed io.WriteCloser
-		compressed, err = compression.CompressStream(cw, compression.Gzip)
+		compressed, err = compression.CompressStream(cw, compressionType)
 		if err != nil {
 			return emptyDesc, fmt.Errorf("failed to get compressed stream: %w", err)
 		}