prevent retained tag with same digest deleted by other tag

Signed-off-by: Ziming Zhang <zziming@vmware.com>
Change-Id: I6a69b405b454ca0350677204e06bfa2b24616b33

src/pkg/retention/dep/client.go

@@ -109,6 +109,7 @@ func (bc *basicClient) GetCandidates(repository *res.Repository) ([]*res.Candida
 				Namespace:    repository.Namespace,
 				Repository:   repository.Name,
 				Tag:          image.Name,
+				Digest:       image.Digest,
 				Labels:       labels,
 				CreationTime: image.Created.Unix(),
 				PulledTime:   image.PullTime.Unix(),

src/pkg/retention/policy/alg/or/processor_test.go

@@ -56,6 +56,7 @@ func (suite *ProcessorTestSuite) SetupSuite() {
 			Repository: "harbor",
 			Kind:       "image",
 			Tag:        "latest",
+			Digest:     "latest",
 			PushedTime: time.Now().Unix(),
 			Labels:     []string{"L1", "L2"},
 		},
@@ -64,6 +65,7 @@ func (suite *ProcessorTestSuite) SetupSuite() {
 			Repository: "harbor",
 			Kind:       "image",
 			Tag:        "dev",
+			Digest:     "dev",
 			PushedTime: time.Now().Unix(),
 			Labels:     []string{"L3"},
 		},

src/pkg/retention/res/candidate.go

@@ -72,6 +72,8 @@ type Candidate struct {
 	Kind string
 	// Tag info
 	Tag string
+	// Digest
+	Digest string
 	// Pushed time in seconds
 	PushedTime int64
 	// Pulled time in seconds
@@ -84,7 +86,10 @@ type Candidate struct {
 
 // Hash code based on the candidate info for differentiation
 func (c *Candidate) Hash() string {
-	raw := fmt.Sprintf("%s:%s/%s:%s", c.Kind, c.Namespace, c.Repository, c.Tag)
+	if c.Digest == "" {
+		panic("Lack Digest of Candidate")
+	}
+	raw := fmt.Sprintf("%s:%s/%s:%s", c.Kind, c.Namespace, c.Repository, c.Digest)
 
 	return base64.StdEncoding.EncodeToString([]byte(raw))
 }