def RenewMapping(self):
    try:
      res = self.pool.urlopen("POST", "/server/mapping")
      if res.status != constants.RESPONSE_OK:
        raise errors.DataServerError("Could not get server mapping from data "
                                     "master.")
      mapping = rdf_data_server.DataServerMapping(res.data)
      self.handler_cls.SERVICE.SaveServerMapping(mapping)
      return mapping
    except urllib3.exceptions.MaxRetryError:
      raise errors.DataServerError("Error when attempting to communicate with"
                                   " data master.")
Ask master server for mapping.
dataset/ETHPy150Open google/grr/grr/server/data_server/data_server.py/StandardDataServer.RenewMapping