Merge pull request #2814 from fuweid/support_legacy_media_type

bugfix: support application/octet-stream during pull

client.go

@@ -403,12 +403,22 @@ func (c *Client) fetch(ctx context.Context, rCtx *RemoteContext, ref string, lim
 	}
 
 	var (
-		schema1Converter *schema1.Converter
-		handler          images.Handler
+		handler images.Handler
+
+		isConvertible bool
+		converterFunc func(context.Context, ocispec.Descriptor) (ocispec.Descriptor, error)
 	)
+
 	if desc.MediaType == images.MediaTypeDockerSchema1Manifest && rCtx.ConvertSchema1 {
-		schema1Converter = schema1.NewConverter(store, fetcher)
+		schema1Converter := schema1.NewConverter(store, fetcher)
+
 		handler = images.Handlers(append(rCtx.BaseHandlers, schema1Converter)...)
+
+		isConvertible = true
+
+		converterFunc = func(ctx context.Context, _ ocispec.Descriptor) (ocispec.Descriptor, error) {
+			return schema1Converter.Convert(ctx)
+		}
 	} else {
 		// Get all the children for a descriptor
 		childrenHandler := images.ChildrenHandler(store)
@@ -421,18 +431,34 @@ func (c *Client) fetch(ctx context.Context, rCtx *RemoteContext, ref string, lim
 			childrenHandler = images.LimitManifests(childrenHandler, rCtx.PlatformMatcher, limit)
 		}
 
+		// set isConvertible to true if there is application/octet-stream media type
+		convertibleHandler := images.HandlerFunc(
+			func(_ context.Context, desc ocispec.Descriptor) ([]ocispec.Descriptor, error) {
+				if desc.MediaType == docker.LegacyConfigMediaType {
+					isConvertible = true
+				}
+
+				return []ocispec.Descriptor{}, nil
+			},
+		)
+
 		handler = images.Handlers(append(rCtx.BaseHandlers,
 			remotes.FetchHandler(store, fetcher),
+			convertibleHandler,
 			childrenHandler,
 		)...)
+
+		converterFunc = func(ctx context.Context, desc ocispec.Descriptor) (ocispec.Descriptor, error) {
+			return docker.ConvertManifest(ctx, store, desc)
+		}
 	}
 
 	if err := images.Dispatch(ctx, handler, desc); err != nil {
 		return images.Image{}, err
 	}
-	if schema1Converter != nil {
-		desc, err = schema1Converter.Convert(ctx)
-		if err != nil {
+
+	if isConvertible {
+		if desc, err = converterFunc(ctx, desc); err != nil {
 			return images.Image{}, err
 		}
 	}

remotes/docker/converter.go

@@ -0,0 +1,88 @@
+/*
+   Copyright The containerd Authors.
+
+   Licensed under the Apache License, Version 2.0 (the "License");
+   you may not use this file except in compliance with the License.
+   You may obtain a copy of the License at
+
+       http://www.apache.org/licenses/LICENSE-2.0
+
+   Unless required by applicable law or agreed to in writing, software
+   distributed under the License is distributed on an "AS IS" BASIS,
+   WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+   See the License for the specific language governing permissions and
+   limitations under the License.
+*/
+
+package docker
+
+import (
+	"bytes"
+	"context"
+	"encoding/json"
+	"fmt"
+
+	"github.com/containerd/containerd/content"
+	"github.com/containerd/containerd/images"
+	"github.com/containerd/containerd/log"
+	"github.com/containerd/containerd/remotes"
+	digest "github.com/opencontainers/go-digest"
+	ocispec "github.com/opencontainers/image-spec/specs-go/v1"
+	"github.com/pkg/errors"
+)
+
+// LegacyConfigMediaType should be replaced by OCI image spec.
+//
+// More detail: docker/distribution#1622
+const LegacyConfigMediaType = "application/octet-stream"
+
+// ConvertManifest changes application/octet-stream to schema2 config media type if need.
+//
+// NOTE:
+// 1. original manifest will be deleted by next gc round.
+// 2. don't cover manifest list.
+func ConvertManifest(ctx context.Context, store content.Store, desc ocispec.Descriptor) (ocispec.Descriptor, error) {
+	if !(desc.MediaType == images.MediaTypeDockerSchema2Manifest ||
+		desc.MediaType == ocispec.MediaTypeImageManifest) {
+
+		log.G(ctx).Warnf("do nothing for media type: %s", desc.MediaType)
+		return desc, nil
+	}
+
+	// read manifest data
+	mb, err := content.ReadBlob(ctx, store, desc)
+	if err != nil {
+		return ocispec.Descriptor{}, errors.Wrap(err, "failed to read index data")
+	}
+
+	var manifest ocispec.Manifest
+	if err := json.Unmarshal(mb, &manifest); err != nil {
+		return ocispec.Descriptor{}, errors.Wrap(err, "failed to unmarshal data into manifest")
+	}
+
+	// check config media type
+	if manifest.Config.MediaType != LegacyConfigMediaType {
+		return desc, nil
+	}
+
+	manifest.Config.MediaType = images.MediaTypeDockerSchema2Config
+	data, err := json.MarshalIndent(manifest, "", "   ")
+	if err != nil {
+		return ocispec.Descriptor{}, errors.Wrap(err, "failed to marshal manifest")
+	}
+
+	// update manifest with gc labels
+	desc.Digest = digest.Canonical.FromBytes(data)
+	desc.Size = int64(len(data))
+
+	labels := map[string]string{}
+	for i, c := range append([]ocispec.Descriptor{manifest.Config}, manifest.Layers...) {
+		labels[fmt.Sprintf("containerd.io/gc.ref.content.%d", i)] = c.Digest.String()
+	}
+
+	ref := remotes.MakeRefKey(ctx, desc)
+	if err := content.WriteBlob(ctx, store, ref, bytes.NewReader(data), desc, content.WithLabels(labels)); err != nil {
+		return ocispec.Descriptor{}, errors.Wrap(err, "failed to update content")
+	}
+	return desc, nil
+}