Times a method that may or may not return a deferred

twisted_timing.py

def time_method(stat_name):
  """
  Attaches a timeout to the deferred returned by the wrapped function.
  After timeout seconds the deferred is canceled and an exception raised.
  """
  def attach_timing(method):
    @functools.wraps(method)
    def wrapper(self, *args, **kwargs):
      start = time()

      # method for recording the timing in the stats object
      def record(result, start):
        end = time() - start
        statistics.add_timing(stat_name, end*1000.0)
        return result

      deferred = False
      try:
        result = method(self, *args, **kwargs)
        if isinstance(result, Deferred):
          deferred = True
          result.addBoth(record, start=start)
        return result
      finally:
        if not deferred:
          record(None, start)

    return wrapper
  return attach_timing