Change error message when trying to pull a deleted or expired tag

Will let the users know they can recover the tag via time machine

Note: This was tested with the Docker protocol, but the new error code is *technically* out of spec; we should make sure its okay.

endpoints/v2/errors.py

@@ -57,6 +57,13 @@ class ManifestUnknown(V2RegistryException):
   def __init__(self, detail=None):
     super(ManifestUnknown, self).__init__('MANIFEST_UNKNOWN', 'manifest unknown', detail, 404)
 
+class TagExpired(V2RegistryException):
+  def __init__(self, message=None, detail=None):
+    super(TagExpired, self).__init__('TAG_EXPIRED',
+                                     message or 'Tag has expired',
+                                     detail,
+                                     404)
+
 
 class ManifestUnverified(V2RegistryException):
   def __init__(self, detail=None):

endpoints/v2/manifest.py

@@ -13,10 +13,11 @@ from endpoints.common import parse_repository_name
 from endpoints.decorators import anon_protect
 from endpoints.notificationhelper import spawn_notification
 from endpoints.v2 import v2_bp, require_repo_read, require_repo_write
-from endpoints.v2.errors import (
-  BlobUnknown, ManifestInvalid, ManifestUnknown, TagInvalid, NameInvalid)
 from endpoints.v2.models_interface import Label
 from endpoints.v2.models_pre_oci import data_model as model
+from endpoints.v2.errors import (BlobUnknown, ManifestInvalid, ManifestUnknown, TagInvalid,
+                                 NameInvalid, TagExpired)
+>>>>>>> Change error message when trying to pull a deleted or expired tag
 from endpoints.v2.labelhandlers import handle_label
 from image.docker import ManifestException
 from image.docker.schema1 import DockerSchema1Manifest, DockerSchema1ManifestBuilder
@@ -43,7 +44,14 @@ def fetch_manifest_by_tagname(namespace_name, repo_name, manifest_ref):
   if manifest is None:
     has_tag = model.has_active_tag(namespace_name, repo_name, manifest_ref)
     if not has_tag:
-      raise ManifestUnknown()
+      has_expired_tag = model.has_tag(namespace_name, repo_name, manifest_ref)
+      if has_expired_tag:
+        logger.debug('Found expired tag %s for repository %s/%s', manifest_ref, namespace_name,
+                     repo_name)
+        msg = 'Tag %s was deleted or has expired. To pull, revive via time machine' % manifest_ref
+        raise TagExpired(msg)
+      else:
+        raise ManifestUnknown()
 
     manifest = _generate_and_store_manifest(namespace_name, repo_name, manifest_ref)
     if manifest is None:

endpoints/v2/models_pre_oci.py

@@ -37,6 +37,13 @@ class PreOCIModel(DockerRegistryV2DataInterface):
     except database.RepositoryTag.DoesNotExist:
       return False
 
+  def has_tag(self, namespace_name, repo_name, tag_name):
+    try:
+      model.tag.get_possibly_expired_tag(namespace_name, repo_name, tag_name)
+      return True
+    except database.RepositoryTag.DoesNotExist:
+      return False
+
   def get_manifest_by_tag(self, namespace_name, repo_name, tag_name):
     try:
       manifest = model.tag.load_tag_manifest(namespace_name, repo_name, tag_name)