codekingpro/portable-devtools

1# Copyright 2020, Google LLC2#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 at6#7#     http://www.apache.org/licenses/LICENSE-2.08#9# Unless required by applicable law or agreed to in writing, software10# 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 and13# limitations under the License.14 15"""AsyncIO implementation of the abstract base Future class."""16 17import asyncio18 19from google.api_core import exceptions20from google.api_core import retry21from google.api_core import retry_async22from google.api_core.future import base23 24 25class _OperationNotComplete(Exception):26    """Private exception used for polling via retry."""27 28    pass29 30 31RETRY_PREDICATE = retry.if_exception_type(32    _OperationNotComplete,33    exceptions.TooManyRequests,34    exceptions.InternalServerError,35    exceptions.BadGateway,36)37DEFAULT_RETRY = retry_async.AsyncRetry(predicate=RETRY_PREDICATE)38 39 40class AsyncFuture(base.Future):41    """A Future that polls peer service to self-update.42 43    The :meth:`done` method should be implemented by subclasses. The polling44    behavior will repeatedly call ``done`` until it returns True.45 46    .. note::47 48        Privacy here is intended to prevent the final class from49        overexposing, not to prevent subclasses from accessing methods.50 51    Args:52        retry (google.api_core.retry.Retry): The retry configuration used53            when polling. This can be used to control how often :meth:`done`54            is polled. Regardless of the retry's ``deadline``, it will be55            overridden by the ``timeout`` argument to :meth:`result`.56    """57 58    def __init__(self, retry=DEFAULT_RETRY):59        super().__init__()60        self._retry = retry61        self._future = asyncio.get_event_loop().create_future()62        self._background_task = None63 64    async def done(self, retry=DEFAULT_RETRY):65        """Checks to see if the operation is complete.66 67        Args:68            retry (google.api_core.retry.Retry): (Optional) How to retry the RPC.69 70        Returns:71            bool: True if the operation is complete, False otherwise.72        """73        # pylint: disable=redundant-returns-doc, missing-raises-doc74        raise NotImplementedError()75 76    async def _done_or_raise(self):77        """Check if the future is done and raise if it's not."""78        result = await self.done()79        if not result:80            raise _OperationNotComplete()81 82    async def running(self):83        """True if the operation is currently running."""84        result = await self.done()85        return not result86 87    async def _blocking_poll(self, timeout=None):88        """Poll and await for the Future to be resolved.89 90        Args:91            timeout (int):92                How long (in seconds) to wait for the operation to complete.93                If None, wait indefinitely.94        """95        if self._future.done():96            return97 98        retry_ = self._retry.with_timeout(timeout)99 100        try:101            await retry_(self._done_or_raise)()102        except exceptions.RetryError:103            raise asyncio.TimeoutError(104                "Operation did not complete within the designated " "timeout."105            )106 107    async def result(self, timeout=None):108        """Get the result of the operation.109 110        Args:111            timeout (int):112                How long (in seconds) to wait for the operation to complete.113                If None, wait indefinitely.114 115        Returns:116            google.protobuf.Message: The Operation's result.117 118        Raises:119            google.api_core.GoogleAPICallError: If the operation errors or if120                the timeout is reached before the operation completes.121        """122        await self._blocking_poll(timeout=timeout)123        return self._future.result()124 125    async def exception(self, timeout=None):126        """Get the exception from the operation.127 128        Args:129            timeout (int): How long to wait for the operation to complete.130                If None, wait indefinitely.131 132        Returns:133            Optional[google.api_core.GoogleAPICallError]: The operation's134                error.135        """136        await self._blocking_poll(timeout=timeout)137        return self._future.exception()138 139    def add_done_callback(self, fn):140        """Add a callback to be executed when the operation is complete.141 142        If the operation is completed, the callback will be scheduled onto the143        event loop. Otherwise, the callback will be stored and invoked when the144        future is done.145 146        Args:147            fn (Callable[Future]): The callback to execute when the operation148                is complete.149        """150        if self._background_task is None:151            self._background_task = asyncio.get_event_loop().create_task(152                self._blocking_poll()153            )154        self._future.add_done_callback(fn)155 156    def set_result(self, result):157        """Set the Future's result."""158        self._future.set_result(result)159 160    def set_exception(self, exception):161        """Set the Future's exception."""162        self._future.set_exception(exception)163