handlers.py 文件源码

def _save_states(self, state, serialized_readers_entity):
    """Run transaction to save state.

    Args:
      state: a model.MapreduceState entity.
      serialized_readers_entity: a model._HugeTaskPayload entity containing
        json serialized input readers.

    Returns:
      False if a fatal error is encountered and this task should be dropped
    immediately. True if transaction is successful. None if a previous
    attempt of this same transaction has already succeeded.
    """
    mr_id = state.key().id_or_name()
    fresh_state = model.MapreduceState.get_by_job_id(mr_id)
    if not self._check_mr_state(fresh_state, mr_id):
      return False
    if fresh_state.active_shards != 0:
      logging.warning(
          "Mapreduce %s already has active shards. Looks like spurious task "
          "execution.", mr_id)
      return None
    config = util.create_datastore_write_config(state.mapreduce_spec)
    db.put([state, serialized_readers_entity], config=config)
    return True