Add child artifact digest in reference model

As we only provide the API to get artifact information via project name, repository name and digest, the digest of child artifact must be returned

Signed-off-by: Wenkai Yin <yinw@vmware.com>

api/v2.0/swagger.yaml

@@ -467,6 +467,9 @@ definitions:
         type: integer
         format: int64
         description: The child ID of the reference
+      child_digest:
+        type: string
+        description: The digest of the child artifact
       platform:
         $ref: '#/definitions/Platform'
   Platform:

src/api/artifact/model.go

@@ -47,8 +47,9 @@ func (a *Artifact) ToSwagger() *models.Artifact {
 	}
 	for _, reference := range a.References {
 		ref := &models.Reference{
-			ChildID:  reference.ChildID,
-			ParentID: reference.ParentID,
+			ChildID:     reference.ChildID,
+			ChildDigest: reference.ChildDigest,
+			ParentID:    reference.ParentID,
 		}
 		if reference.Platform != nil {
 			ref.Platform = &models.Platform{

src/pkg/artifact/manager.go

@@ -127,6 +127,11 @@ func (m *manager) assemble(ctx context.Context, art *dao.Artifact) (*Artifact, e
 	for _, ref := range refs {
 		reference := &Reference{}
 		reference.From(ref)
+		art, err := m.dao.Get(ctx, reference.ChildID)
+		if err != nil {
+			return nil, err
+		}
+		reference.ChildDigest = art.Digest
 		artifact.References = append(artifact.References, reference)
 	}
 	return artifact, nil

src/pkg/artifact/manager_test.go

@@ -105,6 +105,9 @@ func (m *managerTestSuite) TestAssemble() {
 			ChildID:  3,
 		},
 	}, nil)
+	m.dao.On("Get").Return(&dao.Artifact{
+		Digest: "digest",
+	}, nil)
 	artifact, err := m.mgr.assemble(nil, art)
 	m.Require().Nil(err)
 	m.dao.AssertExpectations(m.T())

src/pkg/artifact/model.go

@@ -101,9 +101,10 @@ func (a *Artifact) To() *dao.Artifact {
 
 // Reference records the child artifact referenced by parent artifact
 type Reference struct {
-	ParentID int64
-	ChildID  int64
-	Platform *v1.Platform
+	ParentID    int64
+	ChildID     int64
+	ChildDigest string // As we only provide the API based on digest rather than ID, the digest of child artifact is needed
+	Platform    *v1.Platform
 }
 
 // From converts the data level reference to business level