api: implement delete by tag

README.md

@@ -17,6 +17,7 @@ https://anuvu.github.io/zot/
 * Uses [OCI image layout](https://github.com/opencontainers/image-spec/blob/master/image-layout.md) for image storage
   * Can serve any OCI image layout as a registry 
 * Supports [helm charts](https://helm.sh/docs/topics/registries/)
+* Supports image deletion by tag
 * Currently suitable for on-prem deployments (e.g. colocated with Kubernetes)
 * Compatible with ecosystem tools such as [skopeo](#skopeo) and [cri-o](#cri-o)
 * [Vulnerability scanning of images](#Scanning-images-for-known-vulnerabilities)

pkg/compliance/v1_0_0/check.go

@@ -516,6 +516,14 @@ func CheckWorkflows(t *testing.T, config *compliance.Config) {
 			So(d, ShouldNotBeEmpty)
 			So(d, ShouldEqual, digest.String())
 
+			resp, err = resty.R().SetHeader("Content-Type", "application/vnd.oci.image.manifest.v1+json").
+				SetBody(content).Put(baseURL + "/v2/repo7/manifests/test:1.0.1")
+			So(err, ShouldBeNil)
+			So(resp.StatusCode(), ShouldEqual, 201)
+			d = resp.Header().Get(api.DistContentDigestKey)
+			So(d, ShouldNotBeEmpty)
+			So(d, ShouldEqual, digest.String())
+
 			content = []byte("this is a blob5")
 			digest = godigest.FromBytes(content)
 			So(digest, ShouldNotBeNil)
@@ -565,11 +573,11 @@ func CheckWorkflows(t *testing.T, config *compliance.Config) {
 			So(resp.StatusCode(), ShouldEqual, 200)
 			So(resp.Body(), ShouldNotBeEmpty)
 
-			// delete manifest by tag should fail
+			// delete manifest by tag should pass
 			resp, err = resty.R().Delete(baseURL + "/v2/repo7/manifests/test:1.0")
 			So(err, ShouldBeNil)
-			So(resp.StatusCode(), ShouldEqual, 400)
+			So(resp.StatusCode(), ShouldEqual, 202)
-			// delete manifest by digest
+			// delete manifest by digest (1.0 deleted but 1.0.1 has same reference)
 			resp, err = resty.R().Delete(baseURL + "/v2/repo7/manifests/" + digest.String())
 			So(err, ShouldBeNil)
 			So(resp.StatusCode(), ShouldEqual, 202)
@@ -880,15 +888,6 @@ func CheckWorkflows(t *testing.T, config *compliance.Config) {
 			So(resp.StatusCode(), ShouldEqual, 200)
 			So(resp.Body(), ShouldNotBeEmpty)
 
-			// delete manifest by tag should fail
-			resp, err = resty.R().Delete(baseURL + "/v2/firsttest/first/manifests/test:1.0")
-			So(err, ShouldBeNil)
-			So(resp.StatusCode(), ShouldEqual, 400)
-
-			resp, err = resty.R().Delete(baseURL + "/v2/secondtest/second/manifests/test:1.0")
-			So(err, ShouldBeNil)
-			So(resp.StatusCode(), ShouldEqual, 400)
-
 			// delete manifest by digest
 			resp, err = resty.R().Delete(baseURL + "/v2/firsttest/first/manifests/" + digest.String())
 			So(err, ShouldBeNil)

pkg/storage/storage.go

@@ -588,11 +588,14 @@ func (is *ImageStore) DeleteImageManifest(repo string, reference string) error {
 		return errors.ErrRepoNotFound
 	}
 
-	// as per spec "reference" can only be a digest and not a tag
+	isTag := false
+
+	// as per spec "reference" can be a digest and a tag
 	digest, err := godigest.Parse(reference)
 	if err != nil {
-		is.log.Error().Err(err).Msg("invalid reference")
+		is.log.Debug().Str("invalid digest: ", reference).Msg("storage: assuming tag")
-		return errors.ErrBadManifest
+
+		isTag = true
 	}
 
 	is.Lock()
@@ -620,7 +623,19 @@ func (is *ImageStore) DeleteImageManifest(repo string, reference string) error {
 	outIndex.Manifests = []ispec.Descriptor{}
 
 	for _, m = range index.Manifests {
-		if reference == m.Digest.String() {
+		if isTag {
+			tag, ok := m.Annotations[ispec.AnnotationRefName]
+			if ok && tag == reference {
+				is.log.Debug().Str("deleting tag", tag).Msg("")
+
+				digest = m.Digest
+
+				found = true
+
+				continue
+			}
+		} else if reference == m.Digest.String() {
+			is.log.Debug().Str("deleting reference", reference).Msg("")
 			found = true
 			continue
 		}
@@ -657,9 +672,22 @@ func (is *ImageStore) DeleteImageManifest(repo string, reference string) error {
 		}
 	}
 
-	p := path.Join(dir, "blobs", digest.Algorithm().String(), digest.Encoded())
+	// Delete blob only when blob digest not present in manifest entry.
+	// e.g. 1.0.1 & 1.0.2 have same blob digest so if we delete 1.0.1, blob should not be removed.
+	toDelete := true
 
-	_ = os.Remove(p)
+	for _, m = range outIndex.Manifests {
+		if digest.String() == m.Digest.String() {
+			toDelete = false
+			break
+		}
+	}
+
+	if toDelete {
+		p := path.Join(dir, "blobs", digest.Algorithm().String(), digest.Encoded())
+
+		_ = os.Remove(p)
+	}
 
 	return nil
 }

pkg/storage/storage_test.go

@@ -129,6 +129,8 @@ func TestAPIs(t *testing.T) {
 				})
 
 				Convey("Good image manifest", func() {
+					annotationsMap := make(map[string]string)
+					annotationsMap[ispec.AnnotationRefName] = "1.0"
 					m := ispec.Manifest{
 						Config: ispec.Descriptor{
 							Digest: d,
@@ -141,29 +143,57 @@ func TestAPIs(t *testing.T) {
 								Size:      int64(l),
 							},
 						},
-						Annotations: map[string]string{ispec.AnnotationRefName: "1.0"},
+						Annotations: annotationsMap,
 					}
+
 					m.SchemaVersion = 2
-					mb, _ = json.Marshal(m)
+					mb, _ := json.Marshal(m)
 					d := godigest.FromBytes(mb)
-					_, err = il.PutImageManifest("test", d.String(), ispec.MediaTypeImageManifest, mb)
+					_, err = il.PutImageManifest("test", "1.0", ispec.MediaTypeImageManifest, mb)
 					So(err, ShouldBeNil)
 
-					_, err = il.GetImageTags("test")
+					_, err = il.PutImageManifest("test", "2.0", ispec.MediaTypeImageManifest, mb)
 					So(err, ShouldBeNil)
 
+					_, err = il.PutImageManifest("test", "3.0", ispec.MediaTypeImageManifest, mb)
+					So(err, ShouldBeNil)
+
+					// total tags should be 3 but they have same reference.
+					tags, err := il.GetImageTags("test")
+					So(err, ShouldBeNil)
+					So(len(tags), ShouldEqual, 3)
+
 					_, _, _, err = il.GetImageManifest("test", d.String())
 					So(err, ShouldBeNil)
 
 					err = il.DeleteImageManifest("test", "1.0")
-					So(err, ShouldNotBeNil)
-
-					err = il.DeleteBlob("test", blobDigest.String())
 					So(err, ShouldBeNil)
 
+					tags, err = il.GetImageTags("test")
+					So(err, ShouldBeNil)
+					So(len(tags), ShouldEqual, 2)
+
+					// We deleted only one tag, make sure blob should not be removed.
+					hasBlob, _, err := il.CheckBlob("test", d.String())
+					So(err, ShouldBeNil)
+					So(hasBlob, ShouldEqual, true)
+
+					// If we pass reference all manifest with input reference should be deleted.
 					err = il.DeleteImageManifest("test", d.String())
 					So(err, ShouldBeNil)
 
+					tags, err = il.GetImageTags("test")
+					So(err, ShouldBeNil)
+					So(len(tags), ShouldEqual, 0)
+
+					// All tags/references are deleted, blob should not be present in disk.
+					hasBlob, _, err = il.CheckBlob("test", d.String())
+					So(err, ShouldNotBeNil)
+					So(hasBlob, ShouldEqual, false)
+
+					err = il.DeleteBlob("test", blobDigest.String())
+					So(err, ShouldBeNil)
+
 					_, _, _, err = il.GetImageManifest("test", d.String())
 					So(err, ShouldNotBeNil)
 				})