feat(mutate): added support for overriding manifest annotations (#1056)

Signed-off-by: Batuhan Apaydın <batuhan.apaydin@trendyol.com>
Co-Authored-by: Jon Johnson <jonjohnson@google.com>

- improvements based on feedbacks
- check to make sure we're not trying to mutate annotations on an index

cmd/crane/cmd/mutate.go

@@ -30,6 +30,7 @@ func NewCmdMutate(options *[]crane.Option) *cobra.Command {
 	var lbls []string
 	var entrypoint string
 	var newRef string
+	var anntns []string
 
 	mutateCmd := &cobra.Command{
 		Use:   "mutate",
@@ -38,6 +39,17 @@ func NewCmdMutate(options *[]crane.Option) *cobra.Command {
 		Run: func(_ *cobra.Command, args []string) {
 			// Pull image and get config.
 			ref := args[0]
+
+			if len(anntns) != 0 {
+				desc, err := crane.Head(ref, *options...)
+				if err != nil {
+					log.Fatalf("checking %s: %v", ref, err)
+				}
+				if desc.MediaType.IsIndex() {
+					log.Fatalf("mutating annotations on an index is not yet supported")
+				}
+			}
+
 			img, err := crane.Pull(ref, *options...)
 			if err != nil {
 				log.Fatalf("pulling %s: %v", ref, err)
@@ -52,18 +64,21 @@ func NewCmdMutate(options *[]crane.Option) *cobra.Command {
 			if cfg.Config.Labels == nil {
 				cfg.Config.Labels = map[string]string{}
 			}
-			labels := map[string]string{}
-			for _, l := range lbls {
-				parts := strings.SplitN(l, "=", 2)
-				if len(parts) == 1 {
-					log.Fatalf("parsing label %q, not enough parts", l)
-				}
-				labels[parts[0]] = parts[1]
+
+			labels, err := splitKeyVals(lbls)
+			if err != nil {
+				log.Fatal(err)
 			}
+
 			for k, v := range labels {
 				cfg.Config.Labels[k] = v
 			}
 
+			annotations, err := splitKeyVals(anntns)
+			if err != nil {
+				log.Fatal(err)
+			}
+
 			// Set entrypoint.
 			if entrypoint != "" {
 				// NB: This doesn't attempt to do anything smart about splitting the string into multiple entrypoint elements.
@@ -76,6 +91,12 @@ func NewCmdMutate(options *[]crane.Option) *cobra.Command {
 				log.Fatalf("mutating config: %v", err)
 			}
 
+			// Mutate and write image.
+			img, err = mutate.Annotations(img, annotations)
+			if err != nil {
+				log.Fatalf("mutating annotations: %v", err)
+			}
+
 			// If the new ref isn't provided, write over the original image.
 			// If that ref was provided by digest (e.g., output from
 			// another crane command), then strip that and push the
@@ -100,8 +121,22 @@ func NewCmdMutate(options *[]crane.Option) *cobra.Command {
 			fmt.Println(r.Context().Digest(digest.String()))
 		},
 	}
+	mutateCmd.Flags().StringSliceVarP(&anntns, "annotation", "a", nil, "New annotations to add")
 	mutateCmd.Flags().StringSliceVarP(&lbls, "label", "l", nil, "New labels to add")
 	mutateCmd.Flags().StringVar(&entrypoint, "entrypoint", "", "New entrypoing to set")
 	mutateCmd.Flags().StringVarP(&newRef, "tag", "t", "", "New tag to apply to mutated image. If not provided, push by digest to the original image repository.")
 	return mutateCmd
 }
+
+// splitKeyVals splits key value pairs which is in form hello=world
+func splitKeyVals(kvPairs []string) (map[string]string, error) {
+	m := map[string]string{}
+	for _, l := range kvPairs {
+		parts := strings.SplitN(l, "=", 2)
+		if len(parts) == 1 {
+			return nil, fmt.Errorf("parsing label %q, not enough parts", l)
+		}
+		m[parts[0]] = parts[1]
+	}
+	return m, nil
+}

pkg/v1/mutate/image.go

@@ -30,12 +30,13 @@ type image struct {
 	base v1.Image
 	adds []Addendum
 
-	computed   bool
-	configFile *v1.ConfigFile
-	manifest   *v1.Manifest
-	mediaType  *types.MediaType
-	diffIDMap  map[v1.Hash]v1.Layer
-	digestMap  map[v1.Hash]v1.Layer
+	computed    bool
+	configFile  *v1.ConfigFile
+	manifest    *v1.Manifest
+	annotations map[string]string
+	mediaType   *types.MediaType
+	diffIDMap   map[v1.Hash]v1.Layer
+	digestMap   map[v1.Hash]v1.Layer
 }
 
 var _ v1.Image = (*image)(nil)
@@ -139,6 +140,16 @@ func (i *image) compute() error {
 		}
 	}
 
+	if i.annotations != nil {
+		if manifest.Annotations == nil {
+			manifest.Annotations = map[string]string{}
+		}
+
+		for k, v := range i.annotations {
+			manifest.Annotations[k] = v
+		}
+	}
+
 	i.configFile = configFile
 	i.manifest = manifest
 	i.diffIDMap = diffIDMap

pkg/v1/mutate/mutate.go

@@ -113,6 +113,16 @@ func Config(base v1.Image, cfg v1.Config) (v1.Image, error) {
 	return ConfigFile(base, cf)
 }
 
+// Annotations mutates the provided v1.Image to have the provided annotations
+func Annotations(base v1.Image, annotations map[string]string) (v1.Image, error) {
+	image := &image{
+		base:        base,
+		annotations: annotations,
+	}
+
+	return image, nil
+}
+
 // ConfigFile mutates the provided v1.Image to have the provided v1.ConfigFile
 func ConfigFile(base v1.Image, cfg *v1.ConfigFile) (v1.Image, error) {
 	m, err := base.Manifest()

pkg/v1/mutate/mutate_test.go

@@ -266,6 +266,27 @@ func TestMutateConfig(t *testing.T) {
 	}
 }
 
+func TestAnnotations(t *testing.T) {
+	source := sourceImage(t)
+
+	newAnnotations := map[string]string{
+		"im.the.first.annotation": "hello world",
+	}
+
+	result, err := mutate.Annotations(source, newAnnotations)
+	if err != nil {
+		t.Fatalf("failed to mutate annotations: %v", err)
+	}
+
+	if configDigestsAreEqual(t, source, result) {
+		t.Errorf("mutating the manifest annotations MUST mutate the config digest")
+	}
+
+	if err := validate.Image(result); err != nil {
+		t.Errorf("validate.Image() = %v", err)
+	}
+}
+
 func TestMutateCreatedAt(t *testing.T) {
 	source := sourceImage(t)
 	want := time.Now().Add(-2 * time.Minute)