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/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"`