make scan helper deal with empty response, refs elastic#142

Author: ykhrustalev

elasticsearch/helpers/__init__.py

@@ -173,15 +173,19 @@ def scan(client, query=None, scroll='5m', **kwargs):
  # initial search to
  resp = client.search(body=query, search_type='scan', scroll=scroll, **kwargs)
 
- scroll_id = resp['_scroll_id']
+ scroll_id = resp.get('_scroll_id')
+ if scroll_id is None:
+ return
 
  while True:
  resp = client.scroll(scroll_id, scroll=scroll)
  if not resp['hits']['hits']:
  break
  for hit in resp['hits']['hits']:
  yield hit
- scroll_id = resp['_scroll_id']
+ scroll_id = resp.get('_scroll_id')
+ if scroll_id is None:
+ break
 
 def reindex(client, source_index, target_index, target_client=None, chunk_size=500, scroll='5m'):
  """