python-telegram-bot/telegram/utils/promise.py

58 lines
1.8 KiB
Python

#!/usr/bin/env python
#
# A library that provides a Python interface to the Telegram Bot API
# Copyright (C) 2015-2017
# Leandro Toledo de Souza <devs@python-telegram-bot.org>
#
# This program is free software: you can redistribute it and/or modify
# it under the terms of the GNU Lesser Public License as published by
# the Free Software Foundation, either version 3 of the License, or
# (at your option) any later version.
#
# This program is distributed in the hope that it will be useful,
# but WITHOUT ANY WARRANTY; without even the implied warranty of
# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
# GNU Lesser Public License for more details.
#
# You should have received a copy of the GNU Lesser Public License
# along with this program. If not, see [http://www.gnu.org/licenses/].
""" This module contains the Promise class """
import logging
from threading import Event
logger = logging.getLogger(__name__)
logger.addHandler(logging.NullHandler())
class Promise(object):
"""A simple Promise implementation for the run_async decorator"""
def __init__(self, pooled_function, args, kwargs):
self.pooled_function = pooled_function
self.args = args
self.kwargs = kwargs
self.done = Event()
self._result = None
self._exception = None
def run(self):
try:
self._result = self.pooled_function(*self.args, **self.kwargs)
except Exception as exc:
logger.exception('An uncaught error was raised while running the promise')
self._exception = exc
finally:
self.done.set()
def __call__(self):
self.run()
def result(self, timeout=None):
self.done.wait(timeout=timeout)
if self._exception is not None:
raise self._exception # pylint: disable=raising-bad-type
return self._result