Added raise_on_exception param to streaming_bulk

This means that we can now handle also TransportErrors that might occur
durig the bulk processing and report those items in the failed request
as failed instead of just propagating the exception.

Fixes #166

elasticsearch/helpers/__init__.py

@@ -1,7 +1,7 @@
 from itertools import islice
 from operator import methodcaller
 
-from ..exceptions import ElasticsearchException
+from ..exceptions import ElasticsearchException, TransportError
 from ..compat import map
 
 class BulkIndexError(ElasticsearchException):
@@ -33,7 +33,9 @@ def expand_action(data):
     return action, data.get('_source', data)
 
 
-def streaming_bulk(client, actions, chunk_size=500, raise_on_error=False, expand_action_callback=expand_action, **kwargs):
+def streaming_bulk(client, actions, chunk_size=500, raise_on_error=False,
+        expand_action_callback=expand_action, raise_on_exception=True, 
+        **kwargs):
     """
     Streaming bulk consumes actions from the iterable passed in and yields
     results per action. For non-streaming usecases use
@@ -78,8 +80,10 @@ def streaming_bulk(client, actions, chunk_size=500, raise_on_error=False, expand
     :arg client: instance of :class:`~elasticsearch.Elasticsearch` to use
     :arg actions: iterable containing the actions to be executed
     :arg chunk_size: number of docs in one chunk sent to es (default: 500)
-    :arg raise_on_error: raise `BulkIndexError` containing errors (as `.errors`
+    :arg raise_on_error: raise ``BulkIndexError`` containing errors (as `.errors`
         from the execution of the last chunk)
+    :arg raise_on_exception: if ``False`` then don't propagate exceptions from
+        call to ``bulk`` and just report the items that failed as failed.
     :arg expand_action_callback: callback executed on each action passed in,
         should return a tuple containing the action line and the data line
         (`None` if data line should be omitted).
@@ -100,8 +104,30 @@ def streaming_bulk(client, actions, chunk_size=500, raise_on_error=False, expand
         if not bulk_actions:
             return
 
-        # send the actual request
-        resp = client.bulk(bulk_actions, **kwargs)
+        try:
+            # send the actual request
+            resp = client.bulk(bulk_actions, **kwargs)
+        except TransportError as e:
+            # default behavior - just propagate exception
+            if raise_on_exception:
+                raise e
+
+            # if we are not propagating, mark all actions in current chunk as failed
+            err_message = str(e)
+            exc_errors = []
+            for action, data in chunk:
+                info = {"error": err_message, "status": e.status_code, "exception": e, "data": data}
+                op_type, action = action.popitem()
+                info.update(action)
+                exc_errors.append({op_type: info})
+
+            # emulate standard behavior for failed actions
+            if raise_on_error:
+                raise BulkIndexError('%i document(s) failed to index.' % len(exc_errors), exc_errors)
+            else:
+                for err in exc_errors:
+                    yield False, err
+                continue
 
         # go through request-reponse pairs and detect failures
         for op_type, item in map(methodcaller('popitem'), resp['items']):