fix: proxy cache serve local on remote not found

src/controller/proxy/controller.go

@@ -188,15 +188,9 @@ func (c *controller) UseLocalManifest(ctx context.Context, art lib.ArtifactInfo,
 		return false, nil, err
 	}
 	if !exist || desc == nil {
-		dig, err := c.getManifestDigestInLocal(ctx, art)
-		if err != nil {
-			// skip to delete when error, use debug level log to avoid too many logs when the manifest is removed from upstream
-			log.Debugf("failed to get manifest digest in local, error: %v, skip to delete it, art %+v", err, art)
-		} else {
-			go func() {
-				c.local.DeleteManifest(art.Repository, dig)
-				log.Infof("delete manifest %s with digest %s", art.Repository, dig)
-			}()
+		if a != nil { // if not found, use local if it exists, because a exist, otherwise return error
+			log.Infof("Artifact not found in remote registry but exists in local cache, serving from local: %v:%v", art.Repository, art.Tag)
+			return true, nil, nil
 		}
 		return false, nil, errors.NotFoundError(fmt.Errorf("repo %v, tag %v not found", art.Repository, art.Tag))
 	}

src/controller/proxy/controller_test.go

@@ -147,15 +147,15 @@ func (p *proxyControllerTestSuite) TestUseLocalManifest_429ToLocal() {
 	p.Assert().True(result)
 }
 
-func (p *proxyControllerTestSuite) TestUseLocalManifestWithTag_False() {
+func (p *proxyControllerTestSuite) TestUseLocalManifestWithTag_True() {
 	ctx := context.Background()
 	art := lib.ArtifactInfo{Repository: "library/hello-world", Tag: "latest"}
 	desc := &distribution.Descriptor{}
 	p.local.On("GetManifest", mock.Anything, mock.Anything).Return(&artifact.Artifact{}, nil)
 	p.remote.On("ManifestExist", mock.Anything, mock.Anything).Return(false, desc, nil)
 	result, _, err := p.ctr.UseLocalManifest(ctx, art, p.remote)
-	p.Assert().True(errors.IsNotFoundErr(err))
-	p.Assert().False(result)
+	p.Assert().Nil(err)
+	p.Assert().True(result)
 }
 
 func (p *proxyControllerTestSuite) TestUseLocalBlob_True() {