1# Copyright 2015 gRPC authors. 2# 3# Licensed under the Apache License, Version 2.0 (the "License"); 4# you may not use this file except in compliance with the License. 5# You may obtain a copy of the License at 6# 7# http://www.apache.org/licenses/LICENSE-2.0 8# 9# Unless required by applicable law or agreed to in writing, software 10# distributed under the License is distributed on an "AS IS" BASIS, 11# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. 12# See the License for the specific language governing permissions and 13# limitations under the License. 14 15import threading 16 17from grpc._cython import cygrpc 18 19 20class SimpleFuture(object): 21 """A simple future mechanism.""" 22 23 def __init__(self, function, *args, **kwargs): 24 25 def wrapped_function(): 26 try: 27 self._result = function(*args, **kwargs) 28 except Exception as error: # pylint: disable=broad-except 29 self._error = error 30 31 self._result = None 32 self._error = None 33 self._thread = threading.Thread(target=wrapped_function) 34 self._thread.start() 35 36 def result(self): 37 """The resulting value of this future. 38 39 Re-raises any exceptions. 40 """ 41 self._thread.join() 42 if self._error: 43 # TODO(atash): re-raise exceptions in a way that preserves tracebacks 44 raise self._error # pylint: disable=raising-bad-type 45 return self._result 46 47 48class CompletionQueuePollFuture(SimpleFuture): 49 50 def __init__(self, completion_queue, deadline): 51 super(CompletionQueuePollFuture, 52 self).__init__(lambda: completion_queue.poll(deadline=deadline)) 53