Add load/save image event support

For every docker load and save operations, it would log related
image events.

Signed-off-by: Kai Qiang Wu(Kennan) <wkqwu@cn.ibm.com>
Upstream-commit: 06561057103441fe176910e12674d998b8561b75
Component: engine

components/engine/image/tarexport/load.go

@@ -122,6 +122,7 @@ func (l *tarexporter) Load(inTar io.ReadCloser, outStream io.Writer, quiet bool)
 		}
 
 		parentLinks = append(parentLinks, parentLink{imgID, m.Parent})
+		l.loggerImgEvent.LogImageEvent(imgID.String(), imgID.String(), "load")
 	}
 
 	for _, p := range validatedParentLinks(parentLinks) {

components/engine/image/tarexport/save.go

@@ -158,6 +158,7 @@ func (s *saveSession) save(outStream io.Writer) error {
 
 		parentID, _ := s.is.GetParent(id)
 		parentLinks = append(parentLinks, parentLink{id, parentID})
+		s.tarexporter.loggerImgEvent.LogImageEvent(id.String(), id.String(), "save")
 	}
 
 	for i, p := range validatedParentLinks(parentLinks) {

components/engine/image/tarexport/tarexport.go

@@ -22,16 +22,24 @@ type manifestItem struct {
 }
 
 type tarexporter struct {
-	is image.Store
-	ls layer.Store
-	rs reference.Store
+	is             image.Store
+	ls             layer.Store
+	rs             reference.Store
+	loggerImgEvent LogImageEvent
+}
+
+// LogImageEvent defines interface for event generation related to image tar(load and save) operations
+type LogImageEvent interface {
+	//LogImageEvent generates an event related to an image operation
+	LogImageEvent(imageID, refName, action string)
 }
 
 // NewTarExporter returns new ImageExporter for tar packages
-func NewTarExporter(is image.Store, ls layer.Store, rs reference.Store) image.Exporter {
+func NewTarExporter(is image.Store, ls layer.Store, rs reference.Store, loggerImgEvent LogImageEvent) image.Exporter {
 	return &tarexporter{
-		is: is,
-		ls: ls,
-		rs: rs,
+		is:             is,
+		ls:             ls,
+		rs:             rs,
+		loggerImgEvent: loggerImgEvent,
 	}
 }