Change manifest delete to mark tag as dead and log

endpoints/v2/manifest.py

@@ -388,9 +388,15 @@ def delete_manifest_by_digest(namespace, repo_name, manifest_ref):
     # Without a tag name to reference, we can't make an attempt to generate the manifest
     raise ManifestUnknown()
 
-  manifest.delete_instance()
+  # Mark the tag as no longer alive.
+  try:
+    model.tag.delete_tag(namespace, repo_name, manifest.tag.name)
+  except model.DataModelException:
+    # Tag is not alive.
+    raise ManifestUnknown()
 
-  # TODO(jschorr): Log this as a new log type.
+  track_and_log('delete_tag', manifest.tag.repository,
+                tag=manifest.tag.name, digest=manifest_ref)
 
   return make_response('', 202)