Storage: sourceGeneration in copy_blob googleapis#4533

storage/google/cloud/storage/bucket.py

@@ -654,7 +654,7 @@ def delete_blobs(self, blobs, on_error=None, client=None):
                     raise
 
     def copy_blob(self, blob, destination_bucket, new_name=None,
-                  client=None, preserve_acl=True):
+                  client=None, preserve_acl=True, source_generation=None):
         """Copy the given blob to the given bucket, optionally with a new name.
 
         If :attr:`user_project` is set, bills the API request to that project.
@@ -687,6 +687,9 @@ def copy_blob(self, blob, destination_bucket, new_name=None,
         if self.user_project is not None:
             query_params['userProject'] = self.user_project
 
+        if source_generation is not None:
+            query_params['sourceGeneration'] = source_generation
+
         if new_name is None:
             new_name = blob.name