From c71089c653eb50a878bdcc7fd5ec7dd8f339a836 Mon Sep 17 00:00:00 2001
From: Stephen J Day <stephen.day@docker.com>
Date: Tue, 9 Dec 2014 11:06:51 -0800
Subject: [PATCH] Implement Tags method on ManifestService

---
 storage/manifest.go      | 10 ++++++++++
 storage/manifest_test.go | 14 ++++++++++++++
 storage/manifeststore.go | 30 ++++++++++++++++++++++++++++++
 storage/paths.go         | 10 ++++++++++
 storage/services.go      |  3 +++
 5 files changed, 67 insertions(+)

diff --git a/storage/manifest.go b/storage/manifest.go
index daeaa39b..6c506244 100644
--- a/storage/manifest.go
+++ b/storage/manifest.go
@@ -13,6 +13,16 @@ import (
 	"github.com/docker/docker-registry/digest"
 )
 
+// ErrUnknownRepository is returned if the named repository is not known by
+// the registry.
+type ErrUnknownRepository struct {
+	Name string
+}
+
+func (err ErrUnknownRepository) Error() string {
+	return fmt.Sprintf("unknown respository name=%s", err.Name)
+}
+
 // ErrUnknownManifest is returned if the manifest is not known by the
 // registry.
 type ErrUnknownManifest struct {
diff --git a/storage/manifest_test.go b/storage/manifest_test.go
index e4517943..ea634df8 100644
--- a/storage/manifest_test.go
+++ b/storage/manifest_test.go
@@ -99,6 +99,20 @@ func TestManifestStorage(t *testing.T) {
 	if !reflect.DeepEqual(fetchedManifest, sm) {
 		t.Fatalf("fetched manifest not equal: %#v != %#v", fetchedManifest, sm)
 	}
+
+	// Grabs the tags and check that this tagged manifest is present
+	tags, err := ms.Tags(name)
+	if err != nil {
+		t.Fatalf("unexpected error fetching tags: %v", err)
+	}
+
+	if len(tags) != 1 {
+		t.Fatalf("unexpected tags returned: %v", tags)
+	}
+
+	if tags[0] != tag {
+		t.Fatalf("unexpected tag found in tags: %v != %v", tags, []string{tag})
+	}
 }
 
 type layerKey struct {
diff --git a/storage/manifeststore.go b/storage/manifeststore.go
index ebbc6b3c..33b16390 100644
--- a/storage/manifeststore.go
+++ b/storage/manifeststore.go
@@ -3,6 +3,7 @@ package storage
 import (
 	"encoding/json"
 	"fmt"
+	"path"
 
 	"github.com/docker/docker-registry/storagedriver"
 	"github.com/docker/libtrust"
@@ -16,6 +17,35 @@ type manifestStore struct {
 
 var _ ManifestService = &manifestStore{}
 
+func (ms *manifestStore) Tags(name string) ([]string, error) {
+	p, err := ms.pathMapper.path(manifestTagsPath{
+		name: name,
+	})
+	if err != nil {
+		return nil, err
+	}
+
+	var tags []string
+	entries, err := ms.driver.List(p)
+	if err != nil {
+		logrus.Infof("%#v", err)
+		switch err := err.(type) {
+		case storagedriver.PathNotFoundError:
+			return nil, ErrUnknownRepository{Name: name}
+		default:
+			return nil, err
+		}
+	}
+
+	for _, entry := range entries {
+		_, filename := path.Split(entry)
+
+		tags = append(tags, filename)
+	}
+
+	return tags, nil
+}
+
 func (ms *manifestStore) Exists(name, tag string) (bool, error) {
 	p, err := ms.path(name, tag)
 	if err != nil {
diff --git a/storage/paths.go b/storage/paths.go
index ecc3dd32..a3538b85 100644
--- a/storage/paths.go
+++ b/storage/paths.go
@@ -64,6 +64,8 @@ func (pm *pathMapper) path(spec pathSpec) (string, error) {
 	repoPrefix := append(rootPrefix, "repositories")
 
 	switch v := spec.(type) {
+	case manifestTagsPath:
+		return path.Join(append(repoPrefix, v.name, "manifests")...), nil
 	case manifestPathSpec:
 		// TODO(sday): May need to store manifest by architecture.
 		return path.Join(append(repoPrefix, v.name, "manifests", v.tag)...), nil
@@ -109,6 +111,14 @@ type pathSpec interface {
 	pathSpec()
 }
 
+// manifestTagsPath describes the path elements required to point to the
+// directory with all manifest tags under the repository.
+type manifestTagsPath struct {
+	name string
+}
+
+func (manifestTagsPath) pathSpec() {}
+
 // manifestPathSpec describes the path elements used to build a manifest path.
 // The contents should be a signed manifest json file.
 type manifestPathSpec struct {
diff --git a/storage/services.go b/storage/services.go
index 1f6d5e51..da6d88c5 100644
--- a/storage/services.go
+++ b/storage/services.go
@@ -52,6 +52,9 @@ func (ss *Services) Manifests() ManifestService {
 
 // ManifestService provides operations on image manifests.
 type ManifestService interface {
+	// Tags lists the tags under the named repository.
+	Tags(name string) ([]string, error)
+
 	// Exists returns true if the layer exists.
 	Exists(name, tag string) (bool, error)