5e1fe405a2
To avoid the dead-lock scenario when green futures are being waited on in the same call as non-green futures just disallow this rare and unlikely scenario in the first place. Change-Id: I5b57f7aae94ae40d22047b0b085e4d99e034c2a6
51 lines
1.8 KiB
Python
51 lines
1.8 KiB
Python
# -*- coding: utf-8 -*-
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# Copyright (C) 2013 Yahoo! Inc. All Rights Reserved.
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#
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# Licensed under the Apache License, Version 2.0 (the "License"); you may
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# not use this file except in compliance with the License. You may obtain
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# a copy of the License at
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#
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# http://www.apache.org/licenses/LICENSE-2.0
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#
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# Unless required by applicable law or agreed to in writing, software
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# distributed under the License is distributed on an "AS IS" BASIS, WITHOUT
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# WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. See the
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# License for the specific language governing permissions and limitations
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# under the License.
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from concurrent import futures
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from taskflow.utils import eventlet_utils as eu
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def wait_for_any(fs, timeout=None):
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"""Wait for one of the futures to complete.
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Works correctly with both green and non-green futures (but not both
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together, since this can't be guaranteed to avoid dead-lock due to how
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the waiting implementations are different when green threads are being
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used).
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Returns pair (done futures, not done futures).
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"""
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green_fs = sum(1 for f in fs if isinstance(f, eu.GreenFuture))
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if not green_fs:
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return tuple(futures.wait(fs, timeout=timeout,
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return_when=futures.FIRST_COMPLETED))
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else:
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non_green_fs = len(fs) - green_fs
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if non_green_fs:
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raise RuntimeError("Can not wait on %s green futures and %s"
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" non-green futures in the same `wait_for_any`"
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" call" % (green_fs, non_green_fs))
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else:
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return eu.wait_for_any(fs, timeout=timeout)
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def make_completed_future(result):
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"""Make with completed with given result."""
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future = futures.Future()
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future.set_result(result)
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return future
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