tenacity/async.py

# -*- coding: utf-8 -*-
# Copyright 2016 Étienne Bersac
# Copyright 2016 Julien Danjou
# Copyright 2016 Joshua Harlow
# Copyright 2013-2014 Ray Holder
#
# 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 asyncio
import sys

from monotonic import monotonic as now

from tenacity import BaseRetrying
from tenacity import DoAttempt
from tenacity import DoSleep
from tenacity import NO_RESULT


class AsyncRetrying(BaseRetrying):

    def __init__(self,
                 sleep=asyncio.sleep,
                 **kwargs):
        super(AsyncRetrying, self).__init__(**kwargs)
        self.sleep = sleep

    @asyncio.coroutine
    def call(self, fn, *args, **kwargs):
        self.begin(fn)

        result = NO_RESULT
        exc_info = None
        start_time = now()

        while True:
            do = self.iter(result=result, exc_info=exc_info,
                           start_time=start_time)
            if isinstance(do, DoAttempt):
                try:
                    result = yield from fn(*args, **kwargs)
                    exc_info = None
                    continue
                except Exception:
                    result = NO_RESULT
                    exc_info = sys.exc_info()
                    continue
            elif isinstance(do, DoSleep):
                result = NO_RESULT
                exc_info = None
                yield from self.sleep(do)
            else:
                return do