serialization: remove extra "hierarchy" from mediatypes

The fact that we are serializing is implied. This PR removes the extra
bits in the media type that only serve to confuse and waste bytes. The
new media types better reflect the reality for the usage of each type
and how they relate.

This must be followed up by a split of the serialization document, but
this change _should_ be applied first.

This change is backwards incompatible with previous versions of the OCI
specification. Since we are before 1.0, this is acceptable.

Signed-off-by: Stephen J Day <stephen.day@docker.com>

cmd/oci-image-tool/validate.go

@@ -142,7 +142,7 @@ func (v *validateCmd) validatePath(name string) error {
 		return schema.MediaTypeManifestList.Validate(f)
 
 	case typeConfig:
-		return schema.MediaTypeImageSerializationConfig.Validate(f)
+		return schema.MediaTypeImageConfig.Validate(f)
 	}
 
 	return fmt.Errorf("type %q unimplemented", typ)

image-layout.md

@@ -78,13 +78,13 @@ $ cat ./blobs/sha256-afff3924849e458c5ef237db5f89539274d5e609db5db935ed3959c90f1
   "schemaVersion": 2,
   "mediaType": "application/vnd.oci.image.manifest.v1+json",
   "config": [
-    "mediaType": "application/vnd.oci.image.serialization.config.v1+json",
+    "mediaType": "application/vnd.oci.image.config.v1+json",
     "size": 7023,
     "digest": "sha256:5b0bcabd1ed22e9fb1310cf6c2dec7cdef19f0ad69efa1f392e94a4333501270"
   },
   "layers": [
     {
-      "mediaType": "application/vnd.oci.image.serialization.rootfs.tar.gzip",
+      "mediaType": "application/vnd.oci.image.layer.tar+gzip",
       "size": 32654,
       "digest": "sha256:e692418e4cbaf90ca69d05a66403747baa33ee08806650b51fab815ad7fc331f"
     },

image/config.go

@@ -67,7 +67,7 @@ func findConfig(w walker, d *descriptor) (*config, error) {
 			return errors.Wrapf(err, "%s: error reading config", path)
 		}
 
-		if err := schema.MediaTypeImageSerializationConfig.Validate(bytes.NewReader(buf)); err != nil {
+		if err := schema.MediaTypeImageConfig.Validate(bytes.NewReader(buf)); err != nil {
 			return errors.Wrapf(err, "%s: config validation failed", path)
 		}
 

image/manifest.go

@@ -97,7 +97,7 @@ func (m *manifest) validate(w walker) error {
 
 func (m *manifest) unpack(w walker, dest string) error {
 	for _, d := range m.Layers {
-		if d.MediaType != string(schema.MediaTypeImageSerialization) {
+		if d.MediaType != string(schema.MediaTypeImageConfig) {
 			continue
 		}
 

img/media-types.dot

@@ -2,8 +2,8 @@ digraph G {
   {
     manifestList [shape=note, label="Manifest list\n<<optional>>\napplication/vnd.oci.image.manifest.list.v1+json"]
     manifest [shape=note, label="Image manifest\napplication/vnd.oci.image.manifest.v1+json"]
-    config [shape=note, label="Image JSON\napplication/vnd.oci.image.serialization.config.v1+json"]
-    layer [shape=note, label="Layer tar+gzip\napplication/vnd.oci.image.serialization.rootfs.tar.gzip"]
+    config [shape=note, label="Image JSON\napplication/vnd.oci.image.config.v1+json"]
+    layer [shape=note, label="Layer tar+gzip\napplication/vnd.oci.image.layer.tar+gzip"]
     combined [shape=note, label="Combined image JSON and filesystem changesets\n<<optional>>\napplication/vnd.oci.image.serialization.combined.v1+json"]
   }
 

manifest.md

@@ -158,23 +158,23 @@ Unlike the [Manifest List](#manifest-list), which contains information about a s
   "schemaVersion": 2,
   "mediaType": "application/vnd.oci.image.manifest.v1+json",
   "config": {
-    "mediaType": "application/vnd.oci.image.serialization.config.v1+json",
+    "mediaType": "application/vnd.oci.image.config.v1+json",
     "size": 7023,
     "digest": "sha256:b5b2b2c507a0944348e0303114d8d93aaaa081732b86451d9bce1f432a537bc7"
   },
   "layers": [
     {
-      "mediaType": "application/vnd.oci.image.serialization.rootfs.tar.gzip",
+      "mediaType": "application/vnd.oci.image.layer.tar+gzip",
       "size": 32654,
       "digest": "sha256:e692418e4cbaf90ca69d05a66403747baa33ee08806650b51fab815ad7fc331f"
     },
     {
-      "mediaType": "application/vnd.oci.image.serialization.rootfs.tar.gzip",
+      "mediaType": "application/vnd.oci.image.layer.tar+gzip",
       "size": 16724,
       "digest": "sha256:3c3a4604a545cdc127456d94e421cd355bca5b528f4a9c1905b15da2eb4a4c6b"
     },
     {
-      "mediaType": "application/vnd.oci.image.serialization.rootfs.tar.gzip",
+      "mediaType": "application/vnd.oci.image.layer.tar+gzip",
       "size": 73109,
       "digest": "sha256:ec4b8955958665577945c89419d1af06b5f7636b4ac3da7f12184802ad867736"
     }

media-types.md

@@ -5,8 +5,8 @@ The following `mediaType` MIME types are used by the formats described here, and
 - `application/vnd.oci.descriptor.v1+json`: [Content Descriptor](descriptor.md)
 - `application/vnd.oci.image.manifest.list.v1+json`: [Manifest list](manifest.md#manifest-list)
 - `application/vnd.oci.image.manifest.v1+json`: [Image manifest format](manifest.md#image-manifest)
-- `application/vnd.oci.image.serialization.rootfs.tar.gzip`: ["Layer", as a gzipped tar archive](serialization.md#creating-an-image-filesystem-changeset)
-- `application/vnd.oci.image.serialization.config.v1+json`: [Container config JSON](serialization.md#image-json-description)
+- `application/vnd.oci.image.layer.tar+gzip`: ["Layer", as a gzipped tar archive](serialization.md#creating-an-image-filesystem-changeset)
+- `application/vnd.oci.image.config.v1+json`: [Container config JSON](serialization.md#image-json-description)
 
 ## Compatibility Matrix
 
@@ -32,7 +32,7 @@ This section shows where the OCI Image Specification is compatible with formats
 
 - [application/vnd.docker.image.rootfs.diff.tar.gzip](https://github.com/docker/docker/blob/master/image/spec/v1.md#creating-an-image-filesystem-changeset)
 
-### application/vnd.oci.image.serialization.config.v1+json
+### application/vnd.oci.image.config.v1+json
 
 **Similar/related schema**
 

schema/config_test.go

@@ -156,7 +156,7 @@ func TestConfig(t *testing.T) {
 		},
 	} {
 		r := strings.NewReader(tt.config)
-		err := schema.MediaTypeImageSerializationConfig.Validate(r)
+		err := schema.MediaTypeImageConfig.Validate(r)
 
 		if got := err != nil; tt.fail != got {
 			t.Errorf("test %d: expected validation failure %t but got %t, err %v", i, tt.fail, got, err)

schema/manifest_backwards_compatibility_test.go

@@ -28,7 +28,7 @@ var compatMap = map[string]string{
 	"application/vnd.docker.distribution.manifest.list.v2+json": "application/vnd.oci.image.manifest.list.v1+json",
 	"application/vnd.docker.distribution.manifest.v2+json":      "application/vnd.oci.image.manifest.v1+json",
 	"application/vnd.docker.image.rootfs.diff.tar.gzip":         "application/vnd.oci.image.rootfs.tar.gzip",
-	"application/vnd.docker.container.image.v1+json":            "application/vnd.oci.image.serialization.config.v1+json",
+	"application/vnd.docker.container.image.v1+json":            "application/vnd.oci.image.config.v1+json",
 }
 
 // convertFormats converts Docker v2.2 image format JSON documents to OCI
@@ -220,7 +220,7 @@ func TestBackwardsCompatibilityConfig(t *testing.T) {
 
 		manifest := convertFormats(tt.manifest)
 		r := strings.NewReader(manifest)
-		err := schema.MediaTypeImageSerializationConfig.Validate(r)
+		err := schema.MediaTypeImageConfig.Validate(r)
 
 		if got := err != nil; tt.fail != got {
 			t.Errorf("test %d: expected validation failure %t but got %t, err %v", i, tt.fail, got, err)

schema/manifest_test.go

@@ -66,7 +66,7 @@ func TestManifest(t *testing.T) {
   },
   "layers": [
     {
-      "mediaType": "application/vnd.oci.image.serialization.rootfs.tar.gzip",
+      "mediaType": "application/vnd.oci.image.layer.tar+gzip",
       "size": "675598"
     }
   ]
@@ -88,17 +88,17 @@ func TestManifest(t *testing.T) {
   },
   "layers": [
     {
-      "mediaType": "application/vnd.oci.image.serialization.rootfs.tar.gzip",
+      "mediaType": "application/vnd.oci.image.layer.tar+gzip",
       "size": 675598,
       "digest": "sha256:9d3dd9504c685a304985025df4ed0283e47ac9ffa9bd0326fddf4d59513f0827"
     },
     {
-      "mediaType": "application/vnd.oci.image.serialization.rootfs.tar.gzip",
+      "mediaType": "application/vnd.oci.image.layer.tar+gzip",
       "size": 156,
       "digest": "sha256:2b689805fbd00b2db1df73fae47562faac1a626d5f61744bfe29946ecff5d73d"
     },
     {
-      "mediaType": "application/vnd.oci.image.serialization.rootfs.tar.gzip",
+      "mediaType": "application/vnd.oci.image.layer.tar+gzip",
       "size": 148,
       "digest": "sha256:c57089565e894899735d458f0fd4bb17a0f1e0df8d72da392b85c9b35ee777cd"
     }

schema/schema.go

@@ -18,11 +18,11 @@ import "net/http"
 
 // Media types for the OCI image formats
 const (
-	MediaTypeDescriptor               Validator     = `application/vnd.oci.descriptor.v1+json`
-	MediaTypeManifest                 Validator     = `application/vnd.oci.image.manifest.v1+json`
-	MediaTypeManifestList             Validator     = `application/vnd.oci.image.manifest.list.v1+json`
-	MediaTypeImageSerialization       unimplemented = `application/vnd.oci.image.serialization.rootfs.tar.gzip`
-	MediaTypeImageSerializationConfig Validator     = `application/vnd.oci.image.serialization.config.v1+json`
+	MediaTypeDescriptor   Validator     = `application/vnd.oci.descriptor.v1+json`
+	MediaTypeManifest     Validator     = `application/vnd.oci.image.manifest.v1+json`
+	MediaTypeManifestList Validator     = `application/vnd.oci.image.manifest.list.v1+json`
+	MediaTypeImageConfig  Validator     = `application/vnd.oci.image.config.v1+json`
+	MediaTypeImageLayer   unimplemented = `application/vnd.oci.image.layer.tar+gzip`
 )
 
 var (
@@ -32,10 +32,10 @@ var (
 
 	// specs maps OCI schema media types to schema files.
 	specs = map[Validator]string{
-		MediaTypeDescriptor:               "content-descriptor.json",
-		MediaTypeManifest:                 "image-manifest-schema.json",
-		MediaTypeManifestList:             "manifest-list-schema.json",
-		MediaTypeImageSerializationConfig: "config-schema.json",
+		MediaTypeDescriptor:   "content-descriptor.json",
+		MediaTypeManifest:     "image-manifest-schema.json",
+		MediaTypeManifestList: "manifest-list-schema.json",
+		MediaTypeImageConfig:  "config-schema.json",
 	}
 )
 

serialization.md

@@ -38,7 +38,7 @@ This specification uses the following terms:
     <dd>
 	A layer DiffID is a SHA256 digest over the layer's uncompressed tar archive and serialized in the descriptor digest format, e.g., <code>sha256:a9561eb1b190625c9adb5a9513e72c4dedafc1cb2d4c5236c9a6957ec7dfd5a9</code>.
 	Layers must be packed and unpacked reproducibly to avoid changing the layer ID, for example by using tar-split to save the tar headers.
-	NOTE: the DiffID is different than the digest in the manifest list because the manifest digest is taken over the gzipped layer for `application/vnd.oci.image.serialization.rootfs.tar.gzip` types.
+	NOTE: the DiffID is different than the digest in the manifest list because the manifest digest is taken over the gzipped layer for `application/vnd.oci.image.layer.tar+gzip` types.
     </dd>
     <dt>
         Layer ChainID
@@ -86,7 +86,7 @@ This specification uses the following terms:
 
 Here is an example image JSON file:
 
-```json,title=Image%20JSON&mediatype=application/vnd.oci.image.serialization.config.v1%2Bjson
+```json,title=Image%20JSON&mediatype=application/vnd.oci.image.config.v1%2Bjson
 {  
     "created": "2015-10-31T22:22:56.015925234Z",
     "author": "Alyssa P. Hacker <alyspdev@example.com>",

specs-go/v1/mediatype.go

@@ -25,8 +25,8 @@ const (
 	MediaTypeImageManifestList = "application/vnd.oci.image.manifest.list.v1+json"
 
 	// MediaTypeImageSerialization is the mediaType used for layers referenced by the manifest.
-	MediaTypeImageSerialization = "application/vnd.oci.image.serialization.rootfs.tar.gzip"
+	MediaTypeImageSerialization = "application/vnd.oci.image.layer.tar+gzip"
 
 	// MediaTypeImageSerializationConfig specifies the mediaType for the image configuration.
-	MediaTypeImageSerializationConfig = "application/vnd.oci.image.serialization.config.v1+json"
+	MediaTypeImageSerializationConfig = "application/vnd.oci.image.config.v1+json"
 )