New tests and small fixes while comparing against the V2 spec

Fixes #391

endpoints/v2/blob.py

@@ -30,20 +30,6 @@ class _InvalidRangeHeader(Exception):
   pass
 
 
-@v2_bp.route(BLOB_DIGEST_ROUTE, methods=['HEAD'])
-@process_jwt_auth
-@require_repo_read
-@anon_protect
-def check_blob_existence(namespace, repo_name, digest):
-  try:
-    model.image.get_repo_image_by_storage_checksum(namespace, repo_name, digest)
-
-    # The response body must be empty for a successful HEAD request
-    return make_response('')
-  except model.InvalidImageException:
-    raise BlobUnknown()
-
-
 def _base_blob_fetch(namespace, repo_name, digest):
   """ Some work that is common to both GET and HEAD requests. Callers MUST check for proper
       authorization before calling this method.
@@ -55,6 +41,7 @@ def _base_blob_fetch(namespace, repo_name, digest):
 
   headers = {
     'Docker-Content-Digest': digest,
+    'Content-Length': found.image_size,
   }
 
   # Add the Accept-Ranges header if the storage engine supports resumable
@@ -76,6 +63,7 @@ def check_blob_exists(namespace, repo_name, digest):
 
   response = make_response('')
   response.headers.extend(headers)
+  response.headers['Content-Length'] = headers['Content-Length']
   return response
 
 
@@ -149,8 +137,9 @@ def fetch_existing_upload(namespace, repo_name, upload_uuid):
   except model.InvalidBlobUpload:
     raise BlobUploadUnknown()
 
+  # Note: Docker byte ranges are exclusive so we have to add one to the byte count.
   accepted = make_response('', 204)
-  accepted.headers['Range'] = _render_range(found.byte_count)
+  accepted.headers['Range'] = _render_range(found.byte_count + 1)
   accepted.headers['Docker-Upload-UUID'] = upload_uuid
   return accepted
 
@@ -305,3 +294,15 @@ def cancel_upload(namespace, repo_name, upload_uuid):
   storage.cancel_chunked_upload({found.location.name}, found.uuid, found.storage_metadata)
 
   return make_response('', 204)
+
+
+
+@v2_bp.route('/<namespace>/<repo_name>/blobs/<digest>', methods=['DELETE'])
+@process_jwt_auth
+@require_repo_write
+@anon_protect
+def delete_digest(namespace, repo_name, upload_uuid):
+  # We do not support deleting arbitrary digests, as they break repo images.
+  return make_response('', 501)
+
+