Refactor c/i/image

copy/copy.go

@@ -109,26 +109,26 @@ func Image(ctx *types.SystemContext, policyContext *signature.PolicyContext, des
 	if err != nil {
 		return fmt.Errorf("Error initializing source %s: %v", transports.ImageName(srcRef), err)
 	}
-	src := image.FromSource(rawSource)
-	defer src.Close()
-
-	multiImage, err := src.IsMultiImage()
-	if err != nil {
-		return err
-	}
-	if multiImage {
-		return fmt.Errorf("can not copy %s: manifest contains multiple images", transports.ImageName(srcRef))
-	}
+	unparsedImage := image.UnparsedFromSource(rawSource)
+	defer func() {
+		if unparsedImage != nil {
+			unparsedImage.Close()
+		}
+	}()
 
 	// Please keep this policy check BEFORE reading any other information about the image.
-	if allowed, err := policyContext.IsRunningImageAllowed(src); !allowed || err != nil { // Be paranoid and fail if either return value indicates so.
+	if allowed, err := policyContext.IsRunningImageAllowed(unparsedImage); !allowed || err != nil { // Be paranoid and fail if either return value indicates so.
 		return fmt.Errorf("Source image rejected: %v", err)
 	}
-
-	writeReport("Getting image source manifest\n")
-	manifest, _, err := src.Manifest()
+	src, err := image.FromUnparsedImage(unparsedImage)
 	if err != nil {
-		return fmt.Errorf("Error reading manifest: %v", err)
+		return fmt.Errorf("Error initializing image from source %s: %v", transports.ImageName(srcRef), err)
+	}
+	unparsedImage = nil
+	defer src.Close()
+
+	if src.IsMultiImage() {
+		return fmt.Errorf("can not copy %s: manifest contains multiple images", transports.ImageName(srcRef))
 	}
 
 	var sigs [][]byte
@@ -150,11 +150,7 @@ func Image(ctx *types.SystemContext, policyContext *signature.PolicyContext, des
 	}
 	canModifyManifest := len(sigs) == 0
 
-	writeReport("Getting image source configuration\n")
-	srcConfigInfo, err := src.ConfigInfo()
-	if err != nil {
-		return fmt.Errorf("Error parsing manifest: %v", err)
-	}
+	srcConfigInfo := src.ConfigInfo()
 	if srcConfigInfo.Digest != "" {
 		writeReport("Uploading blob %s\n", srcConfigInfo.Digest)
 		destConfigInfo, err := copyBlob(dest, rawSource, srcConfigInfo, false, reportWriter)
@@ -166,10 +162,7 @@ func Image(ctx *types.SystemContext, policyContext *signature.PolicyContext, des
 		}
 	}
 
-	srcLayerInfos, err := src.LayerInfos()
-	if err != nil {
-		return fmt.Errorf("Error parsing manifest: %v", err)
-	}
+	srcLayerInfos := src.LayerInfos()
 	destLayerInfos := []types.BlobInfo{}
 	copiedLayers := map[string]types.BlobInfo{}
 	for _, srcLayer := range srcLayerInfos {
@@ -190,15 +183,20 @@ func Image(ctx *types.SystemContext, policyContext *signature.PolicyContext, des
 		manifestUpdates.LayerInfos = destLayerInfos
 	}
 
+	pendingImage := src
 	if !reflect.DeepEqual(manifestUpdates, types.ManifestUpdateOptions{}) {
 		if !canModifyManifest {
 			return fmt.Errorf("Internal error: copy needs an updated manifest but that was known to be forbidden")
 		}
-		manifest, err = src.UpdatedManifest(manifestUpdates)
+		pendingImage, err = src.UpdatedImage(manifestUpdates)
 		if err != nil {
 			return fmt.Errorf("Error creating an updated manifest: %v", err)
 		}
 	}
+	manifest, _, err := pendingImage.Manifest()
+	if err != nil {
+		return fmt.Errorf("Error reading manifest: %v", err)
+	}
 
 	if options != nil && options.SignBy != "" {
 		mech, err := signature.NewGPGSigningMechanism()

directory/directory_transport.go

@@ -127,11 +127,13 @@ func (ref dirReference) PolicyConfigurationNamespaces() []string {
 	return res
 }
 
-// NewImage returns a types.Image for this reference.
+// NewImage returns a types.Image for this reference, possibly specialized for this ImageTransport.
 // The caller must call .Close() on the returned Image.
+// NOTE: If any kind of signature verification should happen, build an UnparsedImage from the value returned by NewImageSource,
+// verify that UnparsedImage, and convert it into a real Image via image.FromUnparsedImage.
 func (ref dirReference) NewImage(ctx *types.SystemContext) (types.Image, error) {
 	src := newImageSource(ref)
-	return image.FromSource(src), nil
+	return image.FromSource(src)
 }
 
 // NewImageSource returns a types.ImageSource for this reference,

directory/directory_transport_test.go

@@ -149,6 +149,15 @@ func TestReferencePolicyConfigurationNamespaces(t *testing.T) {
 func TestReferenceNewImage(t *testing.T) {
 	ref, tmpDir := refToTempDir(t)
 	defer os.RemoveAll(tmpDir)
+
+	dest, err := ref.NewImageDestination(nil)
+	require.NoError(t, err)
+	defer dest.Close()
+	err = dest.PutManifest([]byte(`{"schemaVersion":2}`))
+	assert.NoError(t, err)
+	err = dest.Commit()
+	assert.NoError(t, err)
+
 	img, err := ref.NewImage(nil)
 	assert.NoError(t, err)
 	defer img.Close()

docker/docker_image.go

@@ -24,7 +24,11 @@ func newImage(ctx *types.SystemContext, ref dockerReference) (types.Image, error
 	if err != nil {
 		return nil, err
 	}
-	return &Image{Image: image.FromSource(s), src: s}, nil
+	img, err := image.FromSource(s)
+	if err != nil {
+		return nil, err
+	}
+	return &Image{Image: img, src: s}, nil
 }
 
 // SourceRefFullName returns a fully expanded name for the repository this image is in.

docker/docker_transport.go

@@ -115,8 +115,10 @@ func (ref dockerReference) PolicyConfigurationNamespaces() []string {
 	return policyconfiguration.DockerReferenceNamespaces(ref.ref)
 }
 
-// NewImage returns a types.Image for this reference.
+// NewImage returns a types.Image for this reference, possibly specialized for this ImageTransport.
 // The caller must call .Close() on the returned Image.
+// NOTE: If any kind of signature verification should happen, build an UnparsedImage from the value returned by NewImageSource,
+// verify that UnparsedImage, and convert it into a real Image via image.FromUnparsedImage.
 func (ref dockerReference) NewImage(ctx *types.SystemContext) (types.Image, error) {
 	return newImage(ctx, ref)
 }

image/docker_schema1.go

@@ -47,10 +47,27 @@ func manifestSchema1FromManifest(manifest []byte) (genericManifest, error) {
 	return mschema1, nil
 }
 
+func (m *manifestSchema1) serialize() ([]byte, error) {
+	// docker/distribution requires a signature even if the incoming data uses the nominally unsigned DockerV2Schema1MediaType.
+	unsigned, err := json.Marshal(*m)
+	if err != nil {
+		return nil, err
+	}
+	return manifest.AddDummyV2S1Signature(unsigned)
+}
+
+func (m *manifestSchema1) manifestMIMEType() string {
+	return manifest.DockerV2Schema1SignedMediaType
+}
+
+// ConfigInfo returns a complete BlobInfo for the separate config object, or a BlobInfo{Digest:""} if there isn't a separate object.
 func (m *manifestSchema1) ConfigInfo() types.BlobInfo {
 	return types.BlobInfo{}
 }
 
+// LayerInfos returns a list of BlobInfos of layers referenced by this image, in order (the root layer first, and then successive layered layers).
+// The Digest field is guaranteed to be provided; Size may be -1.
+// WARNING: The list may contain duplicates, and they are semantically relevant.
 func (m *manifestSchema1) LayerInfos() []types.BlobInfo {
 	layers := make([]types.BlobInfo, len(m.FSLayers))
 	for i, layer := range m.FSLayers { // NOTE: This includes empty layers (where m.History.V1Compatibility->ThrowAway)
@@ -59,13 +76,13 @@ func (m *manifestSchema1) LayerInfos() []types.BlobInfo {
 	return layers
 }
 
-func (m *manifestSchema1) Config() ([]byte, error) {
+func (m *manifestSchema1) config() ([]byte, error) {
 	return []byte(m.History[0].V1Compatibility), nil
 }
 
-func (m *manifestSchema1) ImageInspectInfo() (*types.ImageInspectInfo, error) {
+func (m *manifestSchema1) imageInspectInfo() (*types.ImageInspectInfo, error) {
 	v1 := &v1Image{}
-	config, err := m.Config()
+	config, err := m.config()
 	if err != nil {
 		return nil, err
 	}
@@ -82,7 +99,9 @@ func (m *manifestSchema1) ImageInspectInfo() (*types.ImageInspectInfo, error) {
 	}, nil
 }
 
-func (m *manifestSchema1) UpdatedManifest(options types.ManifestUpdateOptions) ([]byte, error) {
+// UpdatedImage returns a types.Image modified according to options.
+// This does not change the state of the original Image object.
+func (m *manifestSchema1) UpdatedImage(options types.ManifestUpdateOptions) (types.Image, error) {
 	copy := *m
 	if options.LayerInfos != nil {
 		// Our LayerInfos includes empty layers (where m.History.V1Compatibility->ThrowAway), so expect them to be included here as well.
@@ -96,12 +115,7 @@ func (m *manifestSchema1) UpdatedManifest(options types.ManifestUpdateOptions) (
 			copy.FSLayers[(len(options.LayerInfos)-1)-i].BlobSum = info.Digest
 		}
 	}
-	// docker/distribution requires a signature even if the incoming data uses the nominally unsigned DockerV2Schema1MediaType.
-	unsigned, err := json.Marshal(copy)
-	if err != nil {
-		return nil, err
-	}
-	return manifest.AddDummyV2S1Signature(unsigned)
+	return memoryImageFromManifest(&copy), nil
 }
 
 // fixManifestLayers, after validating the supplied manifest

image/docker_schema2.go

@@ -30,10 +30,22 @@ func manifestSchema2FromManifest(src types.ImageSource, manifest []byte) (generi
 	return &v2s2, nil
 }
 
+func (m *manifestSchema2) serialize() ([]byte, error) {
+	return json.Marshal(*m)
+}
+
+func (m *manifestSchema2) manifestMIMEType() string {
+	return m.MediaType
+}
+
+// ConfigInfo returns a complete BlobInfo for the separate config object, or a BlobInfo{Digest:""} if there isn't a separate object.
 func (m *manifestSchema2) ConfigInfo() types.BlobInfo {
 	return types.BlobInfo{Digest: m.ConfigDescriptor.Digest, Size: m.ConfigDescriptor.Size}
 }
 
+// LayerInfos returns a list of BlobInfos of layers referenced by this image, in order (the root layer first, and then successive layered layers).
+// The Digest field is guaranteed to be provided; Size may be -1.
+// WARNING: The list may contain duplicates, and they are semantically relevant.
 func (m *manifestSchema2) LayerInfos() []types.BlobInfo {
 	blobs := []types.BlobInfo{}
 	for _, layer := range m.LayersDescriptors {
@@ -42,7 +54,7 @@ func (m *manifestSchema2) LayerInfos() []types.BlobInfo {
 	return blobs
 }
 
-func (m *manifestSchema2) Config() ([]byte, error) {
+func (m *manifestSchema2) config() ([]byte, error) {
 	rawConfig, _, err := m.src.GetBlob(m.ConfigDescriptor.Digest)
 	if err != nil {
 		return nil, err
@@ -52,8 +64,8 @@ func (m *manifestSchema2) Config() ([]byte, error) {
 	return config, err
 }
 
-func (m *manifestSchema2) ImageInspectInfo() (*types.ImageInspectInfo, error) {
-	config, err := m.Config()
+func (m *manifestSchema2) imageInspectInfo() (*types.ImageInspectInfo, error) {
+	config, err := m.config()
 	if err != nil {
 		return nil, err
 	}
@@ -70,7 +82,9 @@ func (m *manifestSchema2) ImageInspectInfo() (*types.ImageInspectInfo, error) {
 	}, nil
 }
 
-func (m *manifestSchema2) UpdatedManifest(options types.ManifestUpdateOptions) ([]byte, error) {
+// UpdatedImage returns a types.Image modified according to options.
+// This does not change the state of the original Image object.
+func (m *manifestSchema2) UpdatedImage(options types.ManifestUpdateOptions) (types.Image, error) {
 	copy := *m
 	if options.LayerInfos != nil {
 		if len(copy.LayersDescriptors) != len(options.LayerInfos) {
@@ -81,5 +95,5 @@ func (m *manifestSchema2) UpdatedManifest(options types.ManifestUpdateOptions) (
 			copy.LayersDescriptors[i].Size = info.Size
 		}
 	}
-	return json.Marshal(copy)
+	return memoryImageFromManifest(&copy), nil
 }