Source code for horizon.utils.threaded

# Copyright 2016 Mirantis, Inc.
#
#    Licensed under the Apache License, Version 2.0 (the "License"); you may
#    not use this file except in compliance with the License. You may obtain
#    a copy of the License at
#
#         http://www.apache.org/licenses/LICENSE-2.0
#
#    Unless required by applicable law or agreed to in writing, software
#    distributed under the License is distributed on an "AS IS" BASIS, WITHOUT
#    WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. See the
#    License for the specific language governing permissions and limitations
#    under the License.

import sys
from threading import Thread


[docs]class ThreadedPromise(Thread): def __init__(self, target=None, args=(), kwargs=None, **_kwargs): if kwargs is None: kwargs = {} super(ThreadedPromise, self).__init__(target=target, args=args, kwargs=kwargs, **_kwargs) self.__target = target self.__args = args self.__kwargs = kwargs self.__result = None self.__exc_info = None
[docs] def run(self): try: if self.__target: self.__result = self.__target(*self.__args, **self.__kwargs) except Exception: self.__exc_info = sys.exc_info() finally: # Avoid a refcycle if the thread is running a function with # an argument that has a member that points to the thread. del self.__target, self.__args, self.__kwargs
@property def result(self): self.propagate_exceptions() return self.__result
[docs] def propagate_exceptions(self): self.join() if self.__exc_info is not None: raise self.__exc_info[0], self.__exc_info[1], self.__exc_info[2]
[docs]def promise(func): def wrapped(*args, **kwargs): th_promise = ThreadedPromise(target=func, args=args, kwargs=kwargs) th_promise.start() return th_promise return wrapped