add mimetypes

Signed-off-by: Antonio Murdaca <runcom@redhat.com>

cmd/skopeo/copy.go

@@ -54,7 +54,7 @@ func copyHandler(context *cli.Context) {
 	}
 	signBy := context.String("sign-by")
 
-	manifest, err := src.GetManifest()
+	manifest, _, err := src.GetManifest()
 	if err != nil {
 		logrus.Fatalf("Error reading manifest: %s", err.Error())
 	}

directory/directory.go

@@ -84,8 +84,13 @@ func (s *dirImageSource) IntendedDockerReference() string {
 	return ""
 }
 
-func (s *dirImageSource) GetManifest() ([]byte, error) {
-	return ioutil.ReadFile(manifestPath(s.dir))
+// it's up to the caller to determine the MIME type of the returned manifest's bytes
+func (s *dirImageSource) GetManifest() ([]byte, string, error) {
+	m, err := ioutil.ReadFile(manifestPath(s.dir))
+	if err != nil {
+		return nil, "", err
+	}
+	return m, "", err
 }
 
 func (s *dirImageSource) GetLayer(digest string) (io.ReadCloser, error) {

docker/docker_image.go

@@ -44,7 +44,7 @@ func (i *dockerImage) IntendedDockerReference() string {
 // Manifest is like ImageSource.GetManifest, but the result is cached; it is OK to call this however often you need.
 func (i *dockerImage) Manifest() ([]byte, error) {
 	if i.cachedManifest == nil {
-		m, err := i.src.GetManifest()
+		m, _, err := i.src.GetManifest()
 		if err != nil {
 			return nil, err
 		}

docker/docker_image_src.go

@@ -55,24 +55,24 @@ func (s *dockerImageSource) IntendedDockerReference() string {
 	return fmt.Sprintf("%s:%s", s.ref.Name(), s.tag)
 }
 
-func (s *dockerImageSource) GetManifest() ([]byte, error) {
+func (s *dockerImageSource) GetManifest() ([]byte, string, error) {
 	url := fmt.Sprintf(manifestURL, s.ref.RemoteName(), s.tag)
 	// TODO(runcom) set manifest version header! schema1 for now - then schema2 etc etc and v1
 	// TODO(runcom) NO, switch on the resulter manifest like Docker is doing
 	res, err := s.c.makeRequest("GET", url, nil, nil)
 	if err != nil {
-		return nil, err
+		return nil, "", err
 	}
 	defer res.Body.Close()
 	manblob, err := ioutil.ReadAll(res.Body)
 	if err != nil {
-		return nil, err
+		return nil, "", err
 	}
 	if res.StatusCode != http.StatusOK {
-		return nil, errFetchManifest{res.StatusCode, manblob}
+		return nil, "", errFetchManifest{res.StatusCode, manblob}
 	}
 	// We might validate manblob against the Docker-Content-Digest header here to protect against transport errors.
-	return manblob, nil
+	return manblob, res.Header.Get("Content-Type"), nil
 }
 
 func (s *dockerImageSource) GetLayer(digest string) (io.ReadCloser, error) {

docker/utils/fixtures/v2list.manifest.json

@@ -0,0 +1,56 @@
+{
+   "schemaVersion": 2,
+   "mediaType": "application/vnd.docker.distribution.manifest.list.v2+json",
+   "manifests": [
+      {
+         "mediaType": "application/vnd.docker.distribution.manifest.v1+json",
+         "size": 2094,
+         "digest": "sha256:7820f9a86d4ad15a2c4f0c0e5479298df2aa7c2f6871288e2ef8546f3e7b6783",
+         "platform": {
+            "architecture": "ppc64le",
+            "os": "linux"
+         }
+      },
+      {
+         "mediaType": "application/vnd.docker.distribution.manifest.v1+json",
+         "size": 1922,
+         "digest": "sha256:ae1b0e06e8ade3a11267564a26e750585ba2259c0ecab59ab165ad1af41d1bdd",
+         "platform": {
+            "architecture": "amd64",
+            "os": "linux",
+            "features": [
+               "sse"
+            ]
+         }
+      },
+      {
+         "mediaType": "application/vnd.docker.distribution.manifest.v1+json",
+         "size": 2084,
+         "digest": "sha256:e4c0df75810b953d6717b8f8f28298d73870e8aa2a0d5e77b8391f16fdfbbbe2",
+         "platform": {
+            "architecture": "s390x",
+            "os": "linux"
+         }
+      },
+      {
+         "mediaType": "application/vnd.docker.distribution.manifest.v1+json",
+         "size": 2084,
+         "digest": "sha256:07ebe243465ef4a667b78154ae6c3ea46fdb1582936aac3ac899ea311a701b40",
+         "platform": {
+            "architecture": "arm",
+            "os": "linux",
+            "variant": "armv7"
+         }
+      },
+      {
+         "mediaType": "application/vnd.docker.distribution.manifest.v1+json",
+         "size": 2090,
+         "digest": "sha256:fb2fc0707b86dafa9959fe3d29e66af8787aee4d9a23581714be65db4265ad8a",
+         "platform": {
+            "architecture": "arm64",
+            "os": "linux",
+            "variant": "armv8"
+         }
+      }
+   ]
+}

docker/utils/manifest.go

@@ -10,11 +10,22 @@ import (
 
 // FIXME: Should we just use docker/distribution and docker/docker implementations directly?
 
+// ManifestMIMETypes returns a slice of supported MIME types
+func ManifestMIMETypes() []string {
+	return []string{
+		DockerV2Schema1MIMEType,
+		DockerV2Schema2MIMEType,
+		DockerV2ListMIMEType,
+	}
+}
+
 const (
 	// DockerV2Schema1MIMEType MIME type represents Docker manifest schema 1
 	DockerV2Schema1MIMEType = "application/vnd.docker.distribution.manifest.v1+json"
 	// DockerV2Schema2MIMEType MIME type represents Docker manifest schema 2
 	DockerV2Schema2MIMEType = "application/vnd.docker.distribution.manifest.v2+json"
+	// DockerV2ListMIMEType MIME type represents Docker manifest schema 2 list
+	DockerV2ListMIMEType = "application/vnd.docker.distribution.manifest.list.v2+json"
 )
 
 // GuessManifestMIMEType guesses MIME type of a manifest and returns it _if it is recognized_, or "" if unknown or unrecognized.
@@ -32,7 +43,7 @@ func GuessManifestMIMEType(manifest []byte) string {
 	}
 
 	switch meta.MediaType {
-	case DockerV2Schema2MIMEType: // A recognized type.
+	case DockerV2Schema2MIMEType, DockerV2ListMIMEType: // A recognized type.
 		return meta.MediaType
 	}
 	switch meta.SchemaVersion {

docker/utils/manifest_test.go

@@ -15,6 +15,7 @@ func TestGuessManifestMIMEType(t *testing.T) {
 		mimeType string
 	}{
 		{"v2s2.manifest.json", DockerV2Schema2MIMEType},
+		{"v2list.manifest.json", DockerV2ListMIMEType},
 		{"v2s1.manifest.json", DockerV2Schema1MIMEType},
 		{"v2s1-invalid-signatures.manifest.json", DockerV2Schema1MIMEType},
 		{"v2s2nomime.manifest.json", DockerV2Schema2MIMEType}, // It is unclear whether this one is legal, but we should guess v2s2 if anything at all.

openshift/openshift.go

@@ -193,9 +193,9 @@ func (s *openshiftImageSource) IntendedDockerReference() string {
 	return s.client.canonicalDockerReference()
 }
 
-func (s *openshiftImageSource) GetManifest() ([]byte, error) {
+func (s *openshiftImageSource) GetManifest() ([]byte, string, error) {
 	if err := s.ensureImageIsResolved(); err != nil {
-		return nil, err
+		return nil, "", err
 	}
 	return s.docker.GetManifest()
 }

types/types.go

@@ -27,9 +27,8 @@ type ImageSource interface {
 	// (not as the image itself, or its underlying storage, claims).  This can be used e.g. to determine which public keys are trusted for this image.
 	// May be "" if unknown.
 	IntendedDockerReference() string
-	// GetManifest returns the image's manifest.  It may use a remote (= slow) service.
-	// FIXME? This should also return a MIME type if known, to differentiate between schema versions.
-	GetManifest() ([]byte, error)
+	// GetManifest returns the image's manifest along with its MIME type. The empty string is returned if the MIME type is unknown.  It may use a remote (= slow) service.
+	GetManifest() ([]byte, string, error)
 	// Note: Calling GetLayer() may have ordering dependencies WRT other methods of this type. FIXME: How does this work with (docker save) on stdin?
 	GetLayer(digest string) (io.ReadCloser, error)
 	// GetSignatures returns the image's signatures.  It may use a remote (= slow) service.