add tag deletion event

whenever a tag is deleted an event is sent out via the regular
notification channels

Signed-off-by: Manish Tomar <manish.tomar@docker.com>

notifications/bridge.go

@@ -108,6 +108,14 @@ func (b *bridge) BlobDeleted(repo reference.Named, dgst digest.Digest) error {
 	return b.createBlobDeleteEventAndWrite(EventActionDelete, repo, dgst)
 }
 
+func (b *bridge) TagDeleted(repo reference.Named, tag string) error {
+	event := b.createEvent(EventActionDelete)
+	event.Target.Repository = repo.Name()
+	event.Target.Tag = tag
+
+	return b.sink.Write(*event)
+}
+
 func (b *bridge) createManifestEventAndWrite(action string, repo reference.Named, sm distribution.Manifest) error {
 	manifestEvent, err := b.createManifestEvent(action, repo, sm)
 	if err != nil {

notifications/bridge_test.go

@@ -97,6 +97,9 @@ func TestEventBridgeManifestPulledWithTag(t *testing.T) {
 func TestEventBridgeManifestDeleted(t *testing.T) {
 	l := createTestEnv(t, testSinkFn(func(events ...Event) error {
 		checkDeleted(t, EventActionDelete, events...)
+		if events[0].Target.Digest != dgst {
+			t.Fatalf("unexpected digest on event target: %q != %q", events[0].Target.Digest, dgst)
+		}
 		return nil
 	}))
 
@@ -106,6 +109,21 @@ func TestEventBridgeManifestDeleted(t *testing.T) {
 	}
 }
 
+func TestEventBridgeTagDeleted(t *testing.T) {
+	l := createTestEnv(t, testSinkFn(func(events ...Event) error {
+		checkDeleted(t, EventActionDelete, events...)
+		if events[0].Target.Tag != m.Tag {
+			t.Fatalf("unexpected tag on event target: %q != %q", events[0].Target.Tag, m.Tag)
+		}
+		return nil
+	}))
+
+	repoRef, _ := reference.WithName(repo)
+	if err := l.TagDeleted(repoRef, m.Tag); err != nil {
+		t.Fatalf("unexpected error notifying tag deletion: %v", err)
+	}
+}
+
 func createTestEnv(t *testing.T, fn testSinkFn) Listener {
 	pk, err := libtrust.GenerateECP256PrivateKey()
 	if err != nil {
@@ -142,14 +160,9 @@ func checkDeleted(t *testing.T, action string, events ...Event) {
 		t.Fatalf("request not equal: %#v != %#v", event.Actor, actor)
 	}
 
-	if event.Target.Digest != dgst {
-		t.Fatalf("unexpected digest on event target: %q != %q", event.Target.Digest, dgst)
-	}
-
 	if event.Target.Repository != repo {
 		t.Fatalf("unexpected repository: %q != %q", event.Target.Repository, repo)
 	}
-
 }
 
 func checkCommonManifest(t *testing.T, action string, events ...Event) {

notifications/listener.go

@@ -5,6 +5,7 @@ import (
 	"net/http"
 
 	"github.com/docker/distribution"
+
 	dcontext "github.com/docker/distribution/context"
 	"github.com/docker/distribution/reference"
 	"github.com/opencontainers/go-digest"
@@ -25,10 +26,16 @@ type BlobListener interface {
 	BlobDeleted(repo reference.Named, desc digest.Digest) error
 }
 
+// RepoListener describes a listener that can respond to repository related events.
+type RepoListener interface {
+	TagDeleted(repo reference.Named, tag string) error
+}
+
 // Listener combines all repository events into a single interface.
 type Listener interface {
 	ManifestListener
 	BlobListener
+	RepoListener
 }
 
 type repositoryListener struct {
@@ -214,3 +221,26 @@ func (bwl *blobWriterListener) Commit(ctx context.Context, desc distribution.Des
 
 	return committed, err
 }
+
+type tagServiceListener struct {
+	distribution.TagService
+	parent *repositoryListener
+}
+
+func (rl *repositoryListener) Tags(ctx context.Context) distribution.TagService {
+	return &tagServiceListener{
+		TagService: rl.Repository.Tags(ctx),
+		parent:     rl,
+	}
+}
+
+func (tagSL *tagServiceListener) Untag(ctx context.Context, tag string) error {
+	if err := tagSL.TagService.Untag(ctx, tag); err != nil {
+		return err
+	}
+	if err := tagSL.parent.listener.TagDeleted(tagSL.parent.Repository.Named(), tag); err != nil {
+		dcontext.GetLogger(ctx).Errorf("error dispatching tag deleted to listener: %v", err)
+		return err
+	}
+	return nil
+}

notifications/listener_test.go

@@ -50,12 +50,12 @@ func TestListener(t *testing.T) {
 		"layer:push":      2,
 		"layer:pull":      2,
 		"layer:delete":    2,
+		"tag:delete":      1,
 	}
 
 	if !reflect.DeepEqual(tl.ops, expectedOps) {
 		t.Fatalf("counts do not match:\n%v\n !=\n%v", tl.ops, expectedOps)
 	}
-
 }
 
 type testListener struct {
@@ -64,7 +64,6 @@ type testListener struct {
 
 func (tl *testListener) ManifestPushed(repo reference.Named, m distribution.Manifest, options ...distribution.ManifestServiceOption) error {
 	tl.ops["manifest:push"]++
-
 	return nil
 }
 
@@ -98,6 +97,11 @@ func (tl *testListener) BlobDeleted(repo reference.Named, d digest.Digest) error
 	return nil
 }
 
+func (tl *testListener) TagDeleted(repo reference.Named, tag string) error {
+	tl.ops["tag:delete"]++
+	return nil
+}
+
 // checkExerciseRegistry takes the registry through all of its operations,
 // carrying out generic checks.
 func checkExerciseRepository(t *testing.T, repository distribution.Repository) {
@@ -200,6 +204,10 @@ func checkExerciseRepository(t *testing.T, repository distribution.Repository) {
 		if err != nil {
 			t.Fatalf("unexpected error deleting blob: %v", err)
 		}
+	}
 
+	err = repository.Tags(ctx).Untag(ctx, m.Tag)
+	if err != nil {
+		t.Fatalf("unexpected error deleting tag: %v", err)
 	}
 }