119 lines
3.7 KiB
Python
119 lines
3.7 KiB
Python
# Copyright 2013 Red Hat, Inc.
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# Copyright 2013 New Dream Network, LLC (DreamHost)
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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 logging
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import sys
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import eventlet
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from eventlet.green import threading as greenthreading
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from eventlet import greenpool
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import greenlet
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from oslo.messaging._executors import base
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from oslo.messaging import localcontext
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from oslo.utils import excutils
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LOG = logging.getLogger(__name__)
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def spawn_with(ctxt, pool):
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"""This is the equivalent of a with statement
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but with the content of the BLOCK statement executed
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into a greenthread
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exception path grab from:
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http://www.python.org/dev/peps/pep-0343/
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"""
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def complete(thread, exit):
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exc = True
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try:
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try:
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thread.wait()
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except Exception:
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exc = False
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if not exit(*sys.exc_info()):
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raise
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finally:
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if exc:
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exit(None, None, None)
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callback = ctxt.__enter__()
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thread = pool.spawn(callback)
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thread.link(complete, ctxt.__exit__)
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return thread
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class EventletExecutor(base.PooledExecutorBase):
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"""A message executor which integrates with eventlet.
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This is an executor which polls for incoming messages from a greenthread
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and dispatches each message in its own greenthread.
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The stop() method kills the message polling greenthread and the wait()
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method waits for all message dispatch greenthreads to complete.
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"""
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def __init__(self, conf, listener, dispatcher):
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super(EventletExecutor, self).__init__(conf, listener, dispatcher)
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self._thread = None
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self._greenpool = greenpool.GreenPool(self.conf.rpc_thread_pool_size)
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self._running = False
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if not isinstance(localcontext._STORE, greenthreading.local):
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LOG.debug('eventlet executor in use but the threading module '
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'has not been monkeypatched or has been '
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'monkeypatched after the oslo.messaging library '
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'have been loaded. This will results in unpredictable '
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'behavior. In the future, we will raise a '
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'RuntimeException in this case.')
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def start(self):
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if self._thread is not None:
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return
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@excutils.forever_retry_uncaught_exceptions
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def _executor_thread():
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try:
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while self._running:
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incoming = self.listener.poll()
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if incoming is not None:
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spawn_with(ctxt=self.dispatcher(incoming),
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pool=self._greenpool)
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except greenlet.GreenletExit:
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return
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self._running = True
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self._thread = eventlet.spawn(_executor_thread)
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def stop(self):
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if self._thread is None:
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return
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self._running = False
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self.listener.stop()
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self._thread.cancel()
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def wait(self):
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if self._thread is None:
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return
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self._greenpool.waitall()
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try:
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self._thread.wait()
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except greenlet.GreenletExit:
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pass
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self._thread = None
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