manifest.GuessMIMEType(): recognize self-described OCI manifests

Newer versions of the OCI spec include the mediaType field in image manifests and image indexes, and if they include them, save ourselves some work by using that information. Signed-off-by: Nalin Dahyabhai <nalin@redhat.com>
containers · Nov 29, 2021 · 886a2ed · 886a2ed
1 parent 4f6d0b4
commit 886a2ed
Show file tree

Hide file tree

Showing 23 changed files with 96 additions and 5 deletions.
diff --git a/go.mod b/go.mod
@@ -26,7 +26,7 @@ require (
 	github.com/morikuni/aec v1.0.0 // indirect
 	github.com/mtrmac/gpgme v0.1.2
 	github.com/opencontainers/go-digest v1.0.0
-	github.com/opencontainers/image-spec v1.0.2-0.20210819154149-5ad6f50d6283
+	github.com/opencontainers/image-spec v1.0.2-0.20211123152302-43a7dee1ec31
 	github.com/opencontainers/selinux v1.10.0
 	github.com/ostreedev/ostree-go v0.0.0-20190702140239-759a8c1ac913
 	github.com/pkg/errors v0.9.1

diff --git a/go.sum b/go.sum
@@ -529,6 +529,8 @@ github.com/opencontainers/image-spec v1.0.0/go.mod h1:BtxoFyWECRxE4U/7sNtV5W15zM
 github.com/opencontainers/image-spec v1.0.1/go.mod h1:BtxoFyWECRxE4U/7sNtV5W15zMzWCbyJoFRP3s7yZA0=
 github.com/opencontainers/image-spec v1.0.2-0.20210819154149-5ad6f50d6283 h1:TVzvdjOalkJBNkbpPVMAr4KV9QRf2IjfxdyxwAK78Gs=
 github.com/opencontainers/image-spec v1.0.2-0.20210819154149-5ad6f50d6283/go.mod h1:BtxoFyWECRxE4U/7sNtV5W15zMzWCbyJoFRP3s7yZA0=
+github.com/opencontainers/image-spec v1.0.2-0.20211123152302-43a7dee1ec31 h1:Wh4aR2I6JFwySre9m3iHJYuMnvUFE/HT6qAXozRWi/E=
+github.com/opencontainers/image-spec v1.0.2-0.20211123152302-43a7dee1ec31/go.mod h1:BtxoFyWECRxE4U/7sNtV5W15zMzWCbyJoFRP3s7yZA0=
 github.com/opencontainers/runc v0.0.0-20190115041553-12f6a991201f/go.mod h1:qT5XzbpPznkRYVz/mWwUaVBUv2rmF59PVA73FjuZG0U=
 github.com/opencontainers/runc v0.1.1/go.mod h1:qT5XzbpPznkRYVz/mWwUaVBUv2rmF59PVA73FjuZG0U=
 github.com/opencontainers/runc v1.0.0-rc8.0.20190926000215-3e425f80a8c9/go.mod h1:qT5XzbpPznkRYVz/mWwUaVBUv2rmF59PVA73FjuZG0U=

diff --git a/image/fixtures/oci1-all-media-types.json b/image/fixtures/oci1-all-media-types.json
@@ -1,5 +1,6 @@
 {
     "schemaVersion": 2,
+    "mediaType": "application/vnd.oci.image.manifest.v1+json",
     "config": {
         "mediaType": "application/vnd.oci.image.config.v1+json",
         "size": 4651,

diff --git a/image/fixtures/oci1.json b/image/fixtures/oci1.json
@@ -1,5 +1,6 @@
 {
    "schemaVersion": 2,
+   "mediaType": "application/vnd.oci.image.manifest.v1+json",
    "config": {
       "mediaType": "application/vnd.oci.image.config.v1+json",
       "size": 5940,

diff --git a/image/fixtures/oci1index.json b/image/fixtures/oci1index.json
@@ -1,5 +1,6 @@
 {
   "schemaVersion": 2,
+  "mediaType": "application/vnd.oci.image.index.v1+json",
   "manifests": [
     {
       "mediaType": "application/vnd.oci.image.manifest.v1+json",

diff --git a/image/fixtures/schema1-to-oci1.json b/image/fixtures/schema1-to-oci1.json
@@ -1,5 +1,6 @@
 {
     "schemaVersion": 2,
+    "mediaType": "application/vnd.oci.image.manifest.v1+json",
     "config": {
         "mediaType": "application/vnd.oci.image.config.v1+json",
         "size": -1,

diff --git a/image/fixtures/schema2-all-media-types-to-oci1.json b/image/fixtures/schema2-all-media-types-to-oci1.json
@@ -1,5 +1,6 @@
 {
     "schemaVersion": 2,
+    "mediaType": "application/vnd.oci.image.manifest.v1+json",
     "config": {
         "mediaType": "application/vnd.oci.image.config.v1+json",
         "size": 4651,

diff --git a/image/fixtures/schema2-to-oci1.json b/image/fixtures/schema2-to-oci1.json
@@ -1,5 +1,6 @@
 {
 	"schemaVersion": 2,
+	"mediaType": "application/vnd.oci.image.manifest.v1+json",
 	"config": {
 		"mediaType": "application/vnd.oci.image.config.v1+json",
 		"size": 4651,

diff --git a/manifest/fixtures/ociv1.artifact.json b/manifest/fixtures/ociv1.artifact.json
@@ -1,5 +1,6 @@
 {
   "schemaVersion": 2,
+  "mediaType": "application/vnd.oci.image.manifest.v1+json",
   "config": {
     "mediaType": "application/vnd.oci.custom.artifact.config.v1+json",
     "digest": "",

diff --git a/manifest/fixtures/ociv1.image.index.json b/manifest/fixtures/ociv1.image.index.json
@@ -1,5 +1,6 @@
 {
   "schemaVersion": 2,
+  "mediaType": "application/vnd.oci.image.index.v1+json",
   "manifests": [
     {
       "mediaType": "application/vnd.oci.image.manifest.v1+json",

diff --git a/manifest/fixtures/ociv1.manifest.json b/manifest/fixtures/ociv1.manifest.json
@@ -1,5 +1,6 @@
 {
   "schemaVersion": 2,
+  "mediaType": "application/vnd.oci.image.manifest.v1+json",
   "config": {
     "mediaType": "application/vnd.oci.image.config.v1+json",
     "size": 7023,

diff --git a/manifest/fixtures/ociv1.nondistributable.gzip.manifest.json b/manifest/fixtures/ociv1.nondistributable.gzip.manifest.json
@@ -1,5 +1,6 @@
 {
     "schemaVersion": 2,
+    "mediaType": "application/vnd.oci.image.manifest.v1+json",
     "config": {
         "mediaType": "application/vnd.oci.image.config.v1+json",
         "size": 7023,

diff --git a/manifest/fixtures/ociv1.nondistributable.manifest.json b/manifest/fixtures/ociv1.nondistributable.manifest.json
@@ -1,5 +1,6 @@
 {
     "schemaVersion": 2,
+    "mediaType": "application/vnd.oci.image.manifest.v1+json",
     "config": {
         "mediaType": "application/vnd.oci.image.config.v1+json",
         "size": 7023,

diff --git a/manifest/fixtures/ociv1.nondistributable.zstd.manifest.json b/manifest/fixtures/ociv1.nondistributable.zstd.manifest.json
@@ -1,5 +1,6 @@
 {
     "schemaVersion": 2,
+    "mediaType": "application/vnd.oci.image.manifest.v1+json",
     "config": {
         "mediaType": "application/vnd.oci.image.config.v1+json",
         "size": 7023,

diff --git a/manifest/fixtures/ociv1.uncompressed.manifest.json b/manifest/fixtures/ociv1.uncompressed.manifest.json
@@ -1,5 +1,6 @@
 {
     "schemaVersion": 2,
+    "mediaType": "application/vnd.oci.image.manifest.v1+json",
     "config": {
         "mediaType": "application/vnd.oci.image.config.v1+json",
         "size": 7023,

diff --git a/manifest/fixtures/ociv1.zstd.manifest.json b/manifest/fixtures/ociv1.zstd.manifest.json
@@ -1,5 +1,6 @@
 {
     "schemaVersion": 2,
+    "mediaType": "application/vnd.oci.image.manifest.v1+json",
     "config": {
         "mediaType": "application/vnd.oci.image.config.v1+json",
         "size": 7023,

diff --git a/manifest/fixtures/ociv1nomime.artifact.json b/manifest/fixtures/ociv1nomime.artifact.json
@@ -0,0 +1,9 @@
+{
+  "schemaVersion": 2,
+  "config": {
+    "mediaType": "application/vnd.oci.custom.artifact.config.v1+json",
+    "digest": "",
+    "size": 0
+  },
+  "layers": null
+}
diff --git a/manifest/fixtures/ociv1nomime.image.index.json b/manifest/fixtures/ociv1nomime.image.index.json
@@ -0,0 +1,30 @@
+{
+  "schemaVersion": 2,
+  "manifests": [
+    {
+      "mediaType": "application/vnd.oci.image.manifest.v1+json",
+      "size": 7143,
+      "digest": "sha256:e692418e4cbaf90ca69d05a66403747baa33ee08806650b51fab815ad7fc331f",
+      "platform": {
+        "architecture": "ppc64le",
+        "os": "linux"
+      }
+    },
+    {
+      "mediaType": "application/vnd.oci.image.manifest.v1+json",
+      "size": 7682,
+      "digest": "sha256:5b0bcabd1ed22e9fb1310cf6c2dec7cdef19f0ad69efa1f392e94a4333501270",
+      "platform": {
+        "architecture": "amd64",
+        "os": "linux",
+        "os.features": [
+          "sse4"
+        ]
+      }
+    }
+  ],
+  "annotations": {
+    "com.example.key1": "value1",
+    "com.example.key2": "value2"
+  }
+}
diff --git a/manifest/fixtures/ociv1nomime.manifest.json b/manifest/fixtures/ociv1nomime.manifest.json
@@ -0,0 +1,29 @@
+{
+  "schemaVersion": 2,
+  "config": {
+    "mediaType": "application/vnd.oci.image.config.v1+json",
+    "size": 7023,
+    "digest": "sha256:b5b2b2c507a0944348e0303114d8d93aaaa081732b86451d9bce1f432a537bc7"
+  },
+  "layers": [
+    {
+      "mediaType": "application/vnd.oci.image.layer.v1.tar+gzip",
+      "size": 32654,
+      "digest": "sha256:e692418e4cbaf90ca69d05a66403747baa33ee08806650b51fab815ad7fc331f"
+    },
+    {
+      "mediaType": "application/vnd.oci.image.layer.v1.tar+gzip",
+      "size": 16724,
+      "digest": "sha256:3c3a4604a545cdc127456d94e421cd355bca5b528f4a9c1905b15da2eb4a4c6b"
+    },
+    {
+      "mediaType": "application/vnd.oci.image.layer.v1.tar+gzip",
+      "size": 73109,
+      "digest": "sha256:ec4b8955958665577945c89419d1af06b5f7636b4ac3da7f12184802ad867736"
+    }
+  ],
+  "annotations": {
+    "com.example.key1": "value1",
+    "com.example.key2": "value2"
+  }
+}
diff --git a/manifest/manifest.go b/manifest/manifest.go
@@ -110,7 +110,8 @@ func GuessMIMEType(manifest []byte) string {
 	}
 
 	switch meta.MediaType {
-	case DockerV2Schema2MediaType, DockerV2ListMediaType: // A recognized type.
+	case DockerV2Schema2MediaType, DockerV2ListMediaType,
+		imgspecv1.MediaTypeImageManifest, imgspecv1.MediaTypeImageIndex: // A recognized type.
 		return meta.MediaType
 	}
 	// this is the only way the function can return DockerV2Schema1MediaType, and recognizing that is essential for stripping the JWS signatures = computing the correct manifest digest.
@@ -121,9 +122,9 @@ func GuessMIMEType(manifest []byte) string {
 		}
 		return DockerV2Schema1MediaType
 	case 2:
-		// best effort to understand if this is an OCI image since mediaType
-		// isn't in the manifest for OCI anymore
-		// for docker v2s2 meta.MediaType should have been set. But given the data, this is our best guess.
+		// Best effort to understand if this is an OCI image since mediaType
+		// wasn't in the manifest for OCI image-spec < 1.0.2.
+		// For docker v2s2 meta.MediaType should have been set. But given the data, this is our best guess.
 		ociMan := struct {
 			Config struct {
 				MediaType string `json:"mediaType"`

diff --git a/manifest/manifest_test.go b/manifest/manifest_test.go
@@ -32,6 +32,9 @@ func TestGuessMIMEType(t *testing.T) {
 		{"ociv1.manifest.json", imgspecv1.MediaTypeImageManifest},
 		{"ociv1.artifact.json", imgspecv1.MediaTypeImageManifest},
 		{"ociv1.image.index.json", imgspecv1.MediaTypeImageIndex},
+		{"ociv1nomime.manifest.json", imgspecv1.MediaTypeImageManifest},
+		{"ociv1nomime.artifact.json", imgspecv1.MediaTypeImageManifest},
+		{"ociv1nomime.image.index.json", imgspecv1.MediaTypeImageIndex},
 	}
 
 	for _, c := range cases {

diff --git a/manifest/oci.go b/manifest/oci.go
@@ -66,6 +66,7 @@ func OCI1FromComponents(config imgspecv1.Descriptor, layers []imgspecv1.Descript
 	return &OCI1{
 		imgspecv1.Manifest{
 			Versioned: specs.Versioned{SchemaVersion: 2},
+			MediaType: imgspecv1.MediaTypeImageManifest,
 			Config:    config,
 			Layers:    layers,
 		},

diff --git a/manifest/oci_index.go b/manifest/oci_index.go
@@ -119,6 +119,7 @@ func OCI1IndexFromComponents(components []imgspecv1.Descriptor, annotations map[
 	index := OCI1Index{
 		imgspecv1.Index{
 			Versioned:   imgspec.Versioned{SchemaVersion: 2},
+			MediaType:   imgspecv1.MediaTypeImageIndex,
 			Manifests:   make([]imgspecv1.Descriptor, len(components)),
 			Annotations: dupStringStringMap(annotations),
 		},
@@ -195,6 +196,7 @@ func OCI1IndexFromManifest(manifest []byte) (*OCI1Index, error) {
 	index := OCI1Index{
 		Index: imgspecv1.Index{
 			Versioned:   imgspec.Versioned{SchemaVersion: 2},
+			MediaType:   imgspecv1.MediaTypeImageIndex,
 			Manifests:   []imgspecv1.Descriptor{},
 			Annotations: make(map[string]string),
 		},