images: distinguish between tags and digests

Generate an image's RepoDigests list using all applicable digests, and
refrain from outputting a digest in the tag column of the "images"
output.

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

cmd/podman/images.go

@@ -206,9 +206,9 @@ func (i imagesOptions) setOutputFormat() string {
 	if i.quiet {
 		return formats.IDString
 	}
-	format := "table {{.Repository}}\t{{.Tag}}\t"
+	format := "table {{.Repository}}\t{{if .Tag}}{{.Tag}}{{else}}<none>{{end}}\t"
 	if i.noHeading {
-		format = "{{.Repository}}\t{{.Tag}}\t"
+		format = "{{.Repository}}\t{{if .Tag}}{{.Tag}}{{else}}<none>{{end}}\t"
 	}
 	if i.digests {
 		format += "{{.Digest}}\t"
@@ -270,7 +270,7 @@ func getImagesTemplateOutput(ctx context.Context, images []*adapter.ContainerIma
 			imageID = shortID(img.ID())
 		}
 
-		// get all specified repo:tag pairs and print them separately
+		// get all specified repo:tag and repo@digest pairs and print them separately
 		repopairs, err := image.ReposToMap(img.Names())
 		if err != nil {
 			logrus.Errorf("error finding tag/digest for %s", img.ID())
@@ -287,11 +287,16 @@ func getImagesTemplateOutput(ctx context.Context, images []*adapter.ContainerIma
 					lastNumIdx := strings.LastIndexFunc(sizeStr, unicode.IsNumber)
 					sizeStr = sizeStr[:lastNumIdx+1] + " " + sizeStr[lastNumIdx+1:]
 				}
+				var imageDigest digest.Digest
+				if len(tag) == 71 && strings.HasPrefix(tag, "sha256:") {
+					imageDigest = digest.Digest(tag)
+					tag = ""
+				}
 				params := imagesTemplateParams{
 					Repository:  repo,
 					Tag:         tag,
 					ID:          imageID,
-					Digest:      img.Digest(),
+					Digest:      imageDigest,
 					Digests:     img.Digests(),
 					CreatedTime: createdTime,
 					Created:     units.HumanDuration(time.Since(createdTime)) + " ago",
@@ -302,7 +307,6 @@ func getImagesTemplateOutput(ctx context.Context, images []*adapter.ContainerIma
 				if opts.quiet { // Show only one image ID when quiet
 					break outer
 				}
-
 			}
 		}
 	}

libpod/image/image.go

@@ -9,6 +9,7 @@ import (
 	"io/ioutil"
 	"os"
 	"path/filepath"
+	"sort"
 	"strings"
 	"syscall"
 	"time"
@@ -324,29 +325,54 @@ func (i *Image) Manifest(ctx context.Context) ([]byte, string, error) {
 	return imgRef.Manifest(ctx)
 }
 
-// Names returns a string array of names associated with the image
+// Names returns a string array of names associated with the image, which may be a mixture of tags and digests
 func (i *Image) Names() []string {
 	return i.image.Names
 }
 
-// RepoDigests returns a string array of repodigests associated with the image
-func (i *Image) RepoDigests() ([]string, error) {
-	var repoDigests []string
-	imageDigest := i.Digest()
-
+// RepoTags returns a string array of repotags associated with the image
+func (i *Image) RepoTags() ([]string, error) {
+	var repoTags []string
 	for _, name := range i.Names() {
 		named, err := reference.ParseNormalizedNamed(name)
 		if err != nil {
 			return nil, err
 		}
-
-		canonical, err := reference.WithDigest(reference.TrimNamed(named), imageDigest)
-		if err != nil {
-			return nil, err
+		if tagged, isTagged := named.(reference.NamedTagged); isTagged {
+			repoTags = append(repoTags, tagged.String())
 		}
-
-		repoDigests = append(repoDigests, canonical.String())
 	}
+	return repoTags, nil
+}
+
+// RepoDigests returns a string array of repodigests associated with the image
+func (i *Image) RepoDigests() ([]string, error) {
+	var repoDigests []string
+	added := make(map[string]struct{})
+
+	for _, name := range i.Names() {
+		for _, imageDigest := range append(i.Digests(), i.Digest()) {
+			if imageDigest == "" {
+				continue
+			}
+
+			named, err := reference.ParseNormalizedNamed(name)
+			if err != nil {
+				return nil, err
+			}
+
+			canonical, err := reference.WithDigest(reference.TrimNamed(named), imageDigest)
+			if err != nil {
+				return nil, err
+			}
+
+			if _, alreadyInList := added[canonical.String()]; !alreadyInList {
+				repoDigests = append(repoDigests, canonical.String())
+				added[canonical.String()] = struct{}{}
+			}
+		}
+	}
+	sort.Strings(repoDigests)
 	return repoDigests, nil
 }
 
@@ -944,6 +970,11 @@ func (i *Image) Inspect(ctx context.Context) (*inspect.ImageData, error) {
 		size = int64(*usize)
 	}
 
+	repoTags, err := i.RepoTags()
+	if err != nil {
+		return nil, err
+	}
+
 	repoDigests, err := i.RepoDigests()
 	if err != nil {
 		return nil, err
@@ -965,7 +996,7 @@ func (i *Image) Inspect(ctx context.Context) (*inspect.ImageData, error) {
 
 	data := &inspect.ImageData{
 		ID:           i.ID(),
-		RepoTags:     i.Names(),
+		RepoTags:     repoTags,
 		RepoDigests:  repoDigests,
 		Comment:      comment,
 		Created:      ociv1Img.Created,

libpod/image/image_test.go

@@ -247,6 +247,19 @@ func TestImage_RepoDigests(t *testing.T) {
 			}
 
 			assert.Equal(t, test.expected, actual)
+
+			image = &Image{
+				image: &storage.Image{
+					Names:   test.names,
+					Digests: []digest.Digest{dgst},
+				},
+			}
+			actual, err = image.RepoDigests()
+			if err != nil {
+				t.Fatal(err)
+			}
+
+			assert.Equal(t, test.expected, actual)
 		})
 	}
 }

libpod/image/utils.go

@@ -87,18 +87,18 @@ func hasTransport(image string) bool {
 }
 
 // ReposToMap parses the specified repotags and returns a map with repositories
-// as keys and the corresponding arrays of tags as values.
-func ReposToMap(repotags []string) (map[string][]string, error) {
-	// map format is repo -> tag
+// as keys and the corresponding arrays of tags or digests-as-strings as values.
+func ReposToMap(names []string) (map[string][]string, error) {
+	// map format is repo -> []tag-or-digest
 	repos := make(map[string][]string)
-	for _, repo := range repotags {
+	for _, name := range names {
 		var repository, tag string
-		if len(repo) > 0 {
-			named, err := reference.ParseNormalizedNamed(repo)
-			repository = named.Name()
+		if len(name) > 0 {
+			named, err := reference.ParseNormalizedNamed(name)
 			if err != nil {
 				return nil, err
 			}
+			repository = named.Name()
 			if ref, ok := named.(reference.NamedTagged); ok {
 				tag = ref.Tag()
 			} else if ref, ok := named.(reference.Canonical); ok {