API: report multiple digests for images

Be prepared to report multiple image digests for images which contain
multiple manifests but, because they continue to have the same set of
layers and the same configuration, are considered to be the same image.

Signed-off-by: Nalin Dahyabhai <nalin@redhat.com>

API.md

@@ -1675,6 +1675,8 @@ id [string](https://godoc.org/builtin#string)
 
 digest [string](https://godoc.org/builtin#string)
 
+digests [[]string](#[]string)
+
 parentId [string](https://godoc.org/builtin#string)
 
 repoTags [[]string](#[]string)

cmd/podman/images.go

@@ -27,6 +27,7 @@ type imagesTemplateParams struct {
 	Tag         string
 	ID          string
 	Digest      digest.Digest
+	Digests     []digest.Digest
 	Created     string
 	CreatedTime time.Time
 	Size        string
@@ -34,12 +35,13 @@ type imagesTemplateParams struct {
 }
 
 type imagesJSONParams struct {
-	ID       string        `json:"id"`
-	Name     []string      `json:"names"`
-	Digest   digest.Digest `json:"digest"`
-	Created  time.Time     `json:"created"`
-	Size     *uint64       `json:"size"`
-	ReadOnly bool          `json:"readonly"`
+	ID       string          `json:"id"`
+	Name     []string        `json:"names"`
+	Digest   digest.Digest   `json:"digest"`
+	Digests  []digest.Digest `json:"digests"`
+	Created  time.Time       `json:"created"`
+	Size     *uint64         `json:"size"`
+	ReadOnly bool            `json:"readonly"`
 }
 
 type imagesOptions struct {
@@ -290,6 +292,7 @@ func getImagesTemplateOutput(ctx context.Context, images []*adapter.ContainerIma
 					Tag:         tag,
 					ID:          imageID,
 					Digest:      img.Digest(),
+					Digests:     img.Digests(),
 					CreatedTime: createdTime,
 					Created:     units.HumanDuration(time.Since(createdTime)) + " ago",
 					Size:        sizeStr,
@@ -321,6 +324,7 @@ func getImagesJSONOutput(ctx context.Context, images []*adapter.ContainerImage)
 			ID:       img.ID(),
 			Name:     img.Names(),
 			Digest:   img.Digest(),
+			Digests:  img.Digests(),
 			Created:  img.Created(),
 			Size:     size,
 			ReadOnly: img.IsReadOnly(),

cmd/podman/varlink/io.podman.varlink

@@ -58,7 +58,8 @@ type VolumeRemoveOpts (
 
 type Image (
   id: string,
-  digest:   string,
+  digest: string,
+  digests: []string,
   parentId: string,
   repoTags: []string,
   repoDigests: []string,

libpod/image/image.go

@@ -299,6 +299,11 @@ func (i *Image) Digest() digest.Digest {
 	return i.image.Digest
 }
 
+// Digests returns the image's digests
+func (i *Image) Digests() []digest.Digest {
+	return i.image.Digests
+}
+
 // GetManifest returns the image's manifest as a byte array
 // and manifest type as a string.
 func (i *Image) GetManifest(ctx context.Context, instanceDigest *digest.Digest) ([]byte, string, error) {

pkg/adapter/runtime_remote.go

@@ -146,6 +146,7 @@ type remoteImage struct {
 	InputName   string
 	Names       []string
 	Digest      digest.Digest
+	Digests     []digest.Digest
 	isParent    bool
 	Runtime     *LocalRuntime
 	TopLayer    string
@@ -226,10 +227,15 @@ func imageInListToContainerImage(i iopodman.Image, name string, runtime *LocalRu
 	if err != nil {
 		return nil, err
 	}
+	var digests []digest.Digest
+	for _, d := range i.Digests {
+		digests = append(digests, digest.Digest(d))
+	}
 	ri := remoteImage{
 		InputName:   name,
 		ID:          i.Id,
 		Digest:      digest.Digest(i.Digest),
+		Digests:     digests,
 		Labels:      i.Labels,
 		RepoTags:    i.RepoTags,
 		RepoDigests: i.RepoTags,
@@ -352,6 +358,11 @@ func (ci *ContainerImage) Digest() digest.Digest {
 	return ci.remoteImage.Digest
 }
 
+// Digests returns the image's digests
+func (ci *ContainerImage) Digests() []digest.Digest {
+	return append([]digest.Digest{}, ci.remoteImage.Digests...)
+}
+
 // Labels returns a map of the image's labels
 func (ci *ContainerImage) Labels(ctx context.Context) (map[string]string, error) {
 	return ci.remoteImage.Labels, nil