adds support for oci manifests and manifestlists

Signed-off-by: Mike Brown <[email protected]>

manifest/manifestlist/manifestlist.go

@@ -7,11 +7,17 @@ import (
 
 	"github.com/docker/distribution"
 	"github.com/docker/distribution/manifest"
+	"github.com/docker/distribution/manifest/ocischema"
 	"github.com/opencontainers/go-digest"
 )
 
-// MediaTypeManifestList specifies the mediaType for manifest lists.
-const MediaTypeManifestList = "application/vnd.docker.distribution.manifest.list.v2+json"
+const (
+	// MediaTypeManifestList specifies the mediaType for manifest lists.
+	MediaTypeManifestList = "application/vnd.docker.distribution.manifest.list.v2+json"
+	// MediaTypeOCIManifestList specifies the mediaType for OCI compliant manifest
+	// lists.
+	MediaTypeOCIManifestList = "application/vnd.oci.image.manifest.list.v1+json"
+)
 
 // SchemaVersion provides a pre-initialized version structure for this
 // packages version of the manifest.
@@ -20,6 +26,13 @@ var SchemaVersion = manifest.Versioned{
 	MediaType:     MediaTypeManifestList,
 }
 
+// OCISchemaVersion provides a pre-initialized version structure for this
+// packages OCIschema version of the manifest.
+var OCISchemaVersion = manifest.Versioned{
+	SchemaVersion: 2,
+	MediaType:     MediaTypeOCIManifestList,
+}
+
 func init() {
 	manifestListFunc := func(b []byte) (distribution.Manifest, distribution.Descriptor, error) {
 		m := new(DeserializedManifestList)
@@ -105,8 +118,15 @@ type DeserializedManifestList struct {
 // DeserializedManifestList which contains the resulting manifest list
 // and its JSON representation.
 func FromDescriptors(descriptors []ManifestDescriptor) (*DeserializedManifestList, error) {
-	m := ManifestList{
-		Versioned: SchemaVersion,
+	var m ManifestList
+	if len(descriptors) > 0 && descriptors[0].Descriptor.MediaType == ocischema.MediaTypeManifest {
+		m = ManifestList{
+			Versioned: OCISchemaVersion,
+		}
+	} else {
+		m = ManifestList{
+			Versioned: SchemaVersion,
+		}
 	}
 
 	m.Manifests = make([]ManifestDescriptor, len(descriptors), len(descriptors))

manifest/manifestlist/manifestlist_test.go

@@ -69,7 +69,7 @@ func TestManifestList(t *testing.T) {
 		t.Fatalf("error creating DeserializedManifestList: %v", err)
 	}
 
-	mediaType, canonical, err := deserialized.Payload()
+	mediaType, canonical, _ := deserialized.Payload()
 
 	if mediaType != MediaTypeManifestList {
 		t.Fatalf("unexpected media type: %s", mediaType)
@@ -109,3 +109,104 @@ func TestManifestList(t *testing.T) {
 		}
 	}
 }
+
+var expectedOCIManifestListSerialization = []byte(`{
+   "schemaVersion": 2,
+   "mediaType": "application/vnd.oci.image.manifest.list.v1+json",
+   "manifests": [
+      {
+         "mediaType": "application/vnd.oci.image.manifest.v1+json",
+         "size": 985,
+         "digest": "sha256:1a9ec845ee94c202b2d5da74a24f0ed2058318bfa9879fa541efaecba272e86b",
+         "platform": {
+            "architecture": "amd64",
+            "os": "linux",
+            "features": [
+               "sse4"
+            ]
+         }
+      },
+      {
+         "mediaType": "application/vnd.oci.image.manifest.v1+json",
+         "size": 2392,
+         "digest": "sha256:6346340964309634683409684360934680934608934608934608934068934608",
+         "platform": {
+            "architecture": "sun4m",
+            "os": "sunos"
+         }
+      }
+   ]
+}`)
+
+func TestOCIManifestList(t *testing.T) {
+	manifestDescriptors := []ManifestDescriptor{
+		{
+			Descriptor: distribution.Descriptor{
+				Digest:    "sha256:1a9ec845ee94c202b2d5da74a24f0ed2058318bfa9879fa541efaecba272e86b",
+				Size:      985,
+				MediaType: "application/vnd.oci.image.manifest.v1+json",
+			},
+			Platform: PlatformSpec{
+				Architecture: "amd64",
+				OS:           "linux",
+				Features:     []string{"sse4"},
+			},
+		},
+		{
+			Descriptor: distribution.Descriptor{
+				Digest:    "sha256:6346340964309634683409684360934680934608934608934608934068934608",
+				Size:      2392,
+				MediaType: "application/vnd.oci.image.manifest.v1+json",
+			},
+			Platform: PlatformSpec{
+				Architecture: "sun4m",
+				OS:           "sunos",
+			},
+		},
+	}
+
+	deserialized, err := FromDescriptors(manifestDescriptors)
+	if err != nil {
+		t.Fatalf("error creating DeserializedManifestList: %v", err)
+	}
+
+	mediaType, canonical, _ := deserialized.Payload()
+
+	if mediaType != MediaTypeOCIManifestList {
+		t.Fatalf("unexpected media type: %s", mediaType)
+	}
+
+	// Check that the canonical field is the same as json.MarshalIndent
+	// with these parameters.
+	p, err := json.MarshalIndent(&deserialized.ManifestList, "", "   ")
+	if err != nil {
+		t.Fatalf("error marshaling manifest list: %v", err)
+	}
+	if !bytes.Equal(p, canonical) {
+		t.Fatalf("manifest bytes not equal: %q != %q", string(canonical), string(p))
+	}
+
+	// Check that the canonical field has the expected value.
+	if !bytes.Equal(expectedOCIManifestListSerialization, canonical) {
+		t.Fatalf("manifest bytes not equal: %q != %q", string(canonical), string(expectedOCIManifestListSerialization))
+	}
+
+	var unmarshalled DeserializedManifestList
+	if err := json.Unmarshal(deserialized.canonical, &unmarshalled); err != nil {
+		t.Fatalf("error unmarshaling manifest: %v", err)
+	}
+
+	if !reflect.DeepEqual(&unmarshalled, deserialized) {
+		t.Fatalf("manifests are different after unmarshaling: %v != %v", unmarshalled, *deserialized)
+	}
+
+	references := deserialized.References()
+	if len(references) != 2 {
+		t.Fatalf("unexpected number of references: %d", len(references))
+	}
+	for i := range references {
+		if !reflect.DeepEqual(references[i], manifestDescriptors[i].Descriptor) {
+			t.Fatalf("unexpected value %d returned by References: %v", i, references[i])
+		}
+	}
+}

manifest/ocischema/builder.go

@@ -0,0 +1,80 @@
+package ocischema
+
+import (
+	"github.com/docker/distribution"
+	"github.com/docker/distribution/context"
+	"github.com/opencontainers/go-digest"
+)
+
+// builder is a type for constructing manifests.
+type builder struct {
+	// bs is a BlobService used to publish the configuration blob.
+	bs distribution.BlobService
+
+	// configJSON references
+	configJSON []byte
+
+	// layers is a list of layer descriptors that gets built by successive
+	// calls to AppendReference.
+	layers []distribution.Descriptor
+}
+
+// NewManifestBuilder is used to build new manifests for the current schema
+// version. It takes a BlobService so it can publish the configuration blob
+// as part of the Build process.
+func NewManifestBuilder(bs distribution.BlobService, configJSON []byte) distribution.ManifestBuilder {
+	mb := &builder{
+		bs:         bs,
+		configJSON: make([]byte, len(configJSON)),
+	}
+	copy(mb.configJSON, configJSON)
+
+	return mb
+}
+
+// Build produces a final manifest from the given references.
+func (mb *builder) Build(ctx context.Context) (distribution.Manifest, error) {
+	m := Manifest{
+		Versioned: SchemaVersion,
+		Layers:    make([]distribution.Descriptor, len(mb.layers)),
+	}
+	copy(m.Layers, mb.layers)
+
+	configDigest := digest.FromBytes(mb.configJSON)
+
+	var err error
+	m.Config, err = mb.bs.Stat(ctx, configDigest)
+	switch err {
+	case nil:
+		// Override MediaType, since Put always replaces the specified media
+		// type with application/octet-stream in the descriptor it returns.
+		m.Config.MediaType = MediaTypeConfig
+		return FromStruct(m)
+	case distribution.ErrBlobUnknown:
+		// nop
+	default:
+		return nil, err
+	}
+
+	// Add config to the blob store
+	m.Config, err = mb.bs.Put(ctx, MediaTypeConfig, mb.configJSON)
+	// Override MediaType, since Put always replaces the specified media
+	// type with application/octet-stream in the descriptor it returns.
+	m.Config.MediaType = MediaTypeConfig
+	if err != nil {
+		return nil, err
+	}
+
+	return FromStruct(m)
+}
+
+// AppendReference adds a reference to the current ManifestBuilder.
+func (mb *builder) AppendReference(d distribution.Describable) error {
+	mb.layers = append(mb.layers, d.Descriptor())
+	return nil
+}
+
+// References returns the current references added to this builder.
+func (mb *builder) References() []distribution.Descriptor {
+	return mb.layers
+}