Fires a new Mount event when blobs are cross-repo mounted

Adds an optional "fromRepository" field to the event target

Signed-off-by: Brian Bland <brian.bland@docker.com>

notifications/bridge.go

@@ -72,6 +72,15 @@ func (b *bridge) BlobPulled(repo string, desc distribution.Descriptor) error {
 	return b.createBlobEventAndWrite(EventActionPull, repo, desc)
 }
 
+func (b *bridge) BlobMounted(repo string, desc distribution.Descriptor, fromRepo string) error {
+	event, err := b.createBlobEvent(EventActionMount, repo, desc)
+	if err != nil {
+		return err
+	}
+	event.Target.FromRepository = fromRepo
+	return b.sink.Write(*event)
+}
+
 func (b *bridge) BlobDeleted(repo string, desc distribution.Descriptor) error {
 	return b.createBlobEventAndWrite(EventActionDelete, repo, desc)
 }

notifications/event.go

@@ -11,6 +11,7 @@ import (
 const (
 	EventActionPull   = "pull"
 	EventActionPush   = "push"
+	EventActionMount  = "mount"
 	EventActionDelete = "delete"
 )
 
@@ -61,6 +62,10 @@ type Event struct {
 		// Repository identifies the named repository.
 		Repository string `json:"repository,omitempty"`
 
+		// FromRepository identifies the named repository which a blob was mounted
+		// from if appropriate.
+		FromRepository string `json:"fromRepository,omitempty"`
+
 		// URL provides a direct link to the content.
 		URL string `json:"url,omitempty"`
 	} `json:"target,omitempty"`

notifications/listener.go

@@ -24,6 +24,7 @@ type ManifestListener interface {
 type BlobListener interface {
 	BlobPushed(repo string, desc distribution.Descriptor) error
 	BlobPulled(repo string, desc distribution.Descriptor) error
+	BlobMounted(repo string, desc distribution.Descriptor, fromRepo string) error
 
 	// TODO(stevvooe): Please note that delete support is still a little shaky
 	// and we'll need to propagate these in the future.
@@ -169,6 +170,17 @@ func (bsl *blobServiceListener) Resume(ctx context.Context, id string) (distribu
 	return bsl.decorateWriter(wr), err
 }
 
+func (bsl *blobServiceListener) Mount(ctx context.Context, sourceRepo string, dgst digest.Digest) (distribution.Descriptor, error) {
+	desc, err := bsl.BlobStore.Mount(ctx, sourceRepo, dgst)
+	if err == nil {
+		if err := bsl.parent.listener.BlobMounted(bsl.parent.Repository.Name(), desc, sourceRepo); err != nil {
+			context.GetLogger(ctx).Errorf("error dispatching layer mount to listener: %v", err)
+		}
+	}
+
+	return desc, err
+}
+
 func (bsl *blobServiceListener) decorateWriter(wr distribution.BlobWriter) distribution.BlobWriter {
 	return &blobWriterListener{
 		BlobWriter: wr,

notifications/listener_test.go

@@ -81,6 +81,11 @@ func (tl *testListener) BlobPulled(repo string, desc distribution.Descriptor) er
 	return nil
 }
 
+func (tl *testListener) BlobMounted(repo string, desc distribution.Descriptor, fromRepo string) error {
+	tl.ops["layer:mount"]++
+	return nil
+}
+
 func (tl *testListener) BlobDeleted(repo string, desc distribution.Descriptor) error {
 	tl.ops["layer:delete"]++
 	return nil