adding some support for annotations at the manifest level

Signed-off-by: Mike Brown <brownwm@us.ibm.com>

manifest/ocischema/builder.go

@@ -18,15 +18,19 @@ type builder struct {
 	// layers is a list of layer descriptors that gets built by successive
 	// calls to AppendReference.
 	layers []distribution.Descriptor
+
+	// Annotations contains arbitrary metadata relating to the targeted content.
+	annotations map[string]string
 }
 
 // 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.
+// as part of the Build process, and annotations.
-func NewManifestBuilder(bs distribution.BlobService, configJSON []byte) distribution.ManifestBuilder {
+func NewManifestBuilder(bs distribution.BlobService, configJSON []byte, annotations map[string]string) distribution.ManifestBuilder {
 	mb := &builder{
 		bs:          bs,
 		configJSON:  make([]byte, len(configJSON)),
+		annotations: annotations,
 	}
 	copy(mb.configJSON, configJSON)
 
@@ -38,6 +42,7 @@ func (mb *builder) Build(ctx context.Context) (distribution.Manifest, error) {
 	m := Manifest{
 		Versioned:   SchemaVersion,
 		Layers:      make([]distribution.Descriptor, len(mb.layers)),
+		Annotations: mb.annotations,
 	}
 	copy(m.Layers, mb.layers)
 

manifest/ocischema/builder_test.go

@@ -88,6 +88,9 @@ func TestBuilder(t *testing.T) {
       ],
       "type": "layers"
     },
+    "annotations": {
+       "hot": "potato"
+    }
     "history": [
       {
         "created": "2015-10-31T22:22:54.690851953Z",
@@ -120,9 +123,10 @@ func TestBuilder(t *testing.T) {
 			MediaType: v1.MediaTypeImageLayerGzip,
 		},
 	}
+	annotations := map[string]string{"hot": "potato"}
 
 	bs := &mockBlobService{descriptors: make(map[digest.Digest]distribution.Descriptor)}
-	builder := NewManifestBuilder(bs, imgJSON)
+	builder := NewManifestBuilder(bs, imgJSON, annotations)
 
 	for _, d := range descriptors {
 		if err := builder.AppendReference(d); err != nil {
@@ -142,6 +146,9 @@ func TestBuilder(t *testing.T) {
 	}
 
 	manifest := built.(*DeserializedManifest).Manifest
+	if manifest.Annotations["hot"] != "potato" {
+		t.Fatalf("unexpected annotation in manifest: %s", manifest.Annotations["hot"])
+	}
 
 	if manifest.Versioned.SchemaVersion != 2 {
 		t.Fatal("SchemaVersion != 2")
@@ -154,7 +161,7 @@ func TestBuilder(t *testing.T) {
 	if target.MediaType != v1.MediaTypeImageConfig {
 		t.Fatalf("unexpected media type in target: %s", target.MediaType)
 	}
-	if target.Size != 1582 {
+	if target.Size != 1632 {
 		t.Fatalf("unexpected size in target: %d", target.Size)
 	}
 

manifest/ocischema/manifest_test.go

@@ -10,7 +10,6 @@ import (
 	"github.com/opencontainers/image-spec/specs-go/v1"
 )
 
-// TODO (mikebrow): add annotations to the test
 var expectedManifestSerialization = []byte(`{
    "schemaVersion": 2,
    "mediaType": "application/vnd.oci.image.manifest.v1+json",
@@ -31,7 +30,10 @@ var expectedManifestSerialization = []byte(`{
             "lettuce": "wrap"
          }
       }
-   ]
+   ],
+   "annotations": {
+      "hot": "potato"
+   }
 }`)
 
 func TestManifest(t *testing.T) {
@@ -51,6 +53,7 @@ func TestManifest(t *testing.T) {
 				Annotations: map[string]string{"lettuce": "wrap"},
 			},
 		},
+		Annotations: map[string]string{"hot": "potato"},
 	}
 
 	deserialized, err := FromStruct(manifest)
@@ -87,6 +90,9 @@ func TestManifest(t *testing.T) {
 	if !reflect.DeepEqual(&unmarshalled, deserialized) {
 		t.Fatalf("manifests are different after unmarshaling: %v != %v", unmarshalled, *deserialized)
 	}
+	if deserialized.Annotations["hot"] != "potato" {
+		t.Fatalf("unexpected annotation in manifest: %s", deserialized.Annotations["hot"])
+	}
 
 	target := deserialized.Target()
 	if target.Digest != "sha256:1a9ec845ee94c202b2d5da74a24f0ed2058318bfa9879fa541efaecba272e86b" {