247 lines
8.4 KiB
Python
247 lines
8.4 KiB
Python
# -*- coding: utf-8 -*-
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# vim: tabstop=4 shiftwidth=4 softtabstop=4
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# Copyright (C) 2012 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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import multiprocessing
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import threading
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from concurrent import futures
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from taskflow.engines.action_engine import graph_action
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from taskflow.engines.action_engine import parallel_action
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from taskflow.engines.action_engine import seq_action
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from taskflow.engines.action_engine import task_action
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from taskflow.patterns import graph_flow as gf
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from taskflow.patterns import linear_flow as lf
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from taskflow.patterns import unordered_flow as uf
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from taskflow.persistence import utils as p_utils
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from taskflow import decorators
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from taskflow import exceptions as exc
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from taskflow import states
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from taskflow import storage as t_storage
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from taskflow import task
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from taskflow.utils import misc
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class ActionEngine(object):
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"""Generic action-based engine.
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Converts the flow to recursive structure of actions.
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"""
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def __init__(self, flow, storage):
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self._failures = []
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self._root = None
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self._flow = flow
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self._lock = threading.RLock()
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self.notifier = misc.TransitionNotifier()
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self.task_notifier = misc.TransitionNotifier()
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self.storage = storage
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def _revert(self, current_failure):
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self._change_state(states.REVERTING)
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self._root.revert(self)
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self._change_state(states.REVERTED)
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self._change_state(states.FAILURE)
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if self._failures:
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if len(self._failures) == 1:
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self._failures[0].reraise()
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else:
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exc_infos = [f.exc_info for f in self._failures]
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raise exc.LinkedException.link(exc_infos)
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else:
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current_failure.reraise()
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def _reset(self):
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self._failures = []
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@decorators.locked
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def run(self):
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self.compile()
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self._reset()
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external_provides = set(self.storage.fetch_all().keys())
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missing = self._flow.requires - external_provides
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if missing:
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raise exc.MissingDependencies(self._flow, sorted(missing))
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self._change_state(states.RUNNING)
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try:
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self._root.execute(self)
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except Exception:
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self._revert(misc.Failure())
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else:
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self._change_state(states.SUCCESS)
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def _change_state(self, state):
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self.storage.set_flow_state(state)
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details = dict(engine=self)
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self.notifier.notify(state, details)
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def on_task_state_change(self, task_action, state, result=None):
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if isinstance(result, misc.Failure):
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self._failures.append(result)
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details = dict(engine=self,
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task_name=task_action.name,
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task_uuid=task_action.uuid,
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result=result)
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self.task_notifier.notify(state, details)
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@decorators.locked
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def compile(self):
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if self._root is None:
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translator = self.translator_cls(self)
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self._root = translator.translate(self._flow)
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class Translator(object):
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def __init__(self, engine):
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self.engine = engine
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def _factory_map(self):
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return []
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def translate(self, pattern):
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"""Translates the pattern into an engine runnable action"""
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if isinstance(pattern, task.BaseTask):
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# Wrap the task into something more useful.
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return task_action.TaskAction(pattern, self.engine)
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# Decompose the flow into something more useful:
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for cls, factory in self._factory_map():
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if isinstance(pattern, cls):
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return factory(pattern)
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raise TypeError('Unknown pattern type: %s (type %s)'
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% (pattern, type(pattern)))
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class SingleThreadedTranslator(Translator):
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def _factory_map(self):
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return [(lf.Flow, self._translate_sequential),
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(uf.Flow, self._translate_sequential),
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(gf.Flow, self._translate_graph)]
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def _translate_sequential(self, pattern):
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action = seq_action.SequentialAction()
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for p in pattern:
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action.add(self.translate(p))
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return action
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def _translate_graph(self, pattern):
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action = graph_action.SequentialGraphAction(pattern.graph)
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for p in pattern:
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action.add(p, self.translate(p))
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return action
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class SingleThreadedActionEngine(ActionEngine):
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translator_cls = SingleThreadedTranslator
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def __init__(self, flow, flow_detail=None, book=None, backend=None):
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if flow_detail is None:
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flow_detail = p_utils.create_flow_detail(flow,
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book=book,
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backend=backend)
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ActionEngine.__init__(self, flow,
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storage=t_storage.Storage(flow_detail, backend))
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class MultiThreadedTranslator(Translator):
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def _factory_map(self):
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return [(lf.Flow, self._translate_sequential),
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# unordered can be run in parallel
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(uf.Flow, self._translate_parallel),
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(gf.Flow, self._translate_graph)]
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def _translate_sequential(self, pattern):
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action = seq_action.SequentialAction()
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for p in pattern:
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action.add(self.translate(p))
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return action
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def _translate_parallel(self, pattern):
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action = parallel_action.ParallelAction()
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for p in pattern:
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action.add(self.translate(p))
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return action
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def _translate_graph(self, pattern):
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# TODO(akarpinska): replace with parallel graph later
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action = graph_action.SequentialGraphAction(pattern.graph)
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for p in pattern:
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action.add(p, self.translate(p))
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return action
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class MultiThreadedActionEngine(ActionEngine):
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translator_cls = MultiThreadedTranslator
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def __init__(self, flow, flow_detail=None, book=None, backend=None,
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executor=None):
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if flow_detail is None:
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flow_detail = p_utils.create_flow_detail(flow,
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book=book,
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backend=backend)
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ActionEngine.__init__(self, flow,
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storage=t_storage.ThreadSafeStorage(flow_detail,
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backend))
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if executor is not None:
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self._executor = executor
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self._owns_executor = False
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self._thread_count = -1
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else:
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self._executor = None
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self._owns_executor = True
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# TODO(harlowja): allow this to be configurable??
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try:
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self._thread_count = multiprocessing.cpu_count() + 1
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except NotImplementedError:
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# NOTE(harlowja): apparently may raise so in this case we will
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# just setup two threads since its hard to know what else we
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# should do in this situation.
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self._thread_count = 2
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@decorators.locked
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def run(self):
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if self._owns_executor:
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if self._executor is not None:
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# The previous shutdown failed, something is very wrong.
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raise exc.InvalidStateException("The previous shutdown() of"
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" the executor powering this"
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" engine failed. Something is"
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" very very wrong.")
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self._executor = futures.ThreadPoolExecutor(self._thread_count)
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try:
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ActionEngine.run(self)
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finally:
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# Don't forget to shutdown the executor!!
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if self._owns_executor and self._executor is not None:
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self._executor.shutdown(wait=True)
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self._executor = None
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@property
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def executor(self):
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return self._executor
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