tenacity/_asyncio.py

# 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 functools
import sys
import typing as t
from asyncio import sleep

from tenacity import AttemptManager
from tenacity import BaseRetrying
from tenacity import DoAttempt
from tenacity import DoSleep
from tenacity import RetryCallState

WrappedFnReturnT = t.TypeVar("WrappedFnReturnT")
WrappedFn = t.TypeVar("WrappedFn", bound=t.Callable[..., t.Awaitable[t.Any]])


class AsyncRetrying(BaseRetrying):
    sleep: t.Callable[[float], t.Awaitable[t.Any]]

    def __init__(self, sleep: t.Callable[[float], t.Awaitable[t.Any]] = sleep, **kwargs: t.Any) -> None:
        super().__init__(**kwargs)
        self.sleep = sleep

    async def __call__(  # type: ignore[override]
        self, fn: WrappedFn, *args: t.Any, **kwargs: t.Any
    ) -> WrappedFnReturnT:
        self.begin()

        retry_state = RetryCallState(retry_object=self, fn=fn, args=args, kwargs=kwargs)
        while True:
            do = self.iter(retry_state=retry_state)
            if isinstance(do, DoAttempt):
                try:
                    result = await fn(*args, **kwargs)
                except BaseException:  # noqa: B902
                    retry_state.set_exception(sys.exc_info())  # type: ignore[arg-type]
                else:
                    retry_state.set_result(result)
            elif isinstance(do, DoSleep):
                retry_state.prepare_for_next_attempt()
                await self.sleep(do)
            else:
                return do  # type: ignore[no-any-return]

    def __iter__(self) -> t.Generator[AttemptManager, None, None]:
        raise TypeError("AsyncRetrying object is not iterable")

    def __aiter__(self) -> "AsyncRetrying":
        self.begin()
        self._retry_state = RetryCallState(self, fn=None, args=(), kwargs={})
        return self

    async def __anext__(self) -> AttemptManager:
        while True:
            do = self.iter(retry_state=self._retry_state)
            if do is None:
                raise StopAsyncIteration
            elif isinstance(do, DoAttempt):
                return AttemptManager(retry_state=self._retry_state)
            elif isinstance(do, DoSleep):
                self._retry_state.prepare_for_next_attempt()
                await self.sleep(do)
            else:
                raise StopAsyncIteration

    def wraps(self, fn: WrappedFn) -> WrappedFn:
        fn = super().wraps(fn)
        # Ensure wrapper is recognized as a coroutine function.

        @functools.wraps(fn)
        async def async_wrapped(*args: t.Any, **kwargs: t.Any) -> t.Any:
            return await fn(*args, **kwargs)

        # Preserve attributes
        async_wrapped.retry = fn.retry  # type: ignore[attr-defined]
        async_wrapped.retry_with = fn.retry_with  # type: ignore[attr-defined]

        return async_wrapped  # type: ignore[return-value]