00bb55edf6
The condition interrupt but is fixed in 3.2 so we can avoid some of the legacy logic in that version (and eventually at some point we can just remove that code). Change-Id: I45a871a212bb06fb69c36405161a9e66601b0f0d
124 lines
3.5 KiB
Python
124 lines
3.5 KiB
Python
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# Copyright 2013 Red Hat, Inc.
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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 abc
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import collections
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import sys
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import threading
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from oslo_log import log as logging
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import six
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from oslo_messaging._drivers import common
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LOG = logging.getLogger(__name__)
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# TODO(harlowja): remove this when we no longer have to support 2.7
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if sys.version_info[0:2] < (3, 2):
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def wait_condition(cond):
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# FIXME(markmc): timeout needed to allow keyboard interrupt
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# http://bugs.python.org/issue8844
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cond.wait(timeout=1)
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else:
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def wait_condition(cond):
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cond.wait()
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@six.add_metaclass(abc.ABCMeta)
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class Pool(object):
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"""A thread-safe object pool.
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Modelled after the eventlet.pools.Pool interface, but designed to be safe
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when using native threads without the GIL.
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Resizing is not supported.
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"""
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def __init__(self, max_size=4):
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super(Pool, self).__init__()
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self._max_size = max_size
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self._current_size = 0
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self._cond = threading.Condition()
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self._items = collections.deque()
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def put(self, item):
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"""Return an item to the pool."""
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with self._cond:
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self._items.appendleft(item)
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self._cond.notify()
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def get(self):
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"""Return an item from the pool, when one is available.
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This may cause the calling thread to block.
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"""
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with self._cond:
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while True:
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try:
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return self._items.popleft()
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except IndexError:
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pass
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if self._current_size < self._max_size:
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self._current_size += 1
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break
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wait_condition(self._cond)
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# We've grabbed a slot and dropped the lock, now do the creation
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try:
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return self.create()
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except Exception:
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with self._cond:
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self._current_size -= 1
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raise
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def iter_free(self):
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"""Iterate over free items."""
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with self._cond:
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while True:
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try:
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yield self._items.popleft()
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except IndexError:
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break
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@abc.abstractmethod
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def create(self):
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"""Construct a new item."""
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class ConnectionPool(Pool):
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"""Class that implements a Pool of Connections."""
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def __init__(self, conf, rpc_conn_pool_size, url, connection_cls):
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self.connection_cls = connection_cls
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self.conf = conf
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self.url = url
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super(ConnectionPool, self).__init__(rpc_conn_pool_size)
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self.reply_proxy = None
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# TODO(comstud): Timeout connections not used in a while
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def create(self, purpose=None):
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if purpose is None:
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purpose = common.PURPOSE_SEND
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LOG.debug('Pool creating new connection')
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return self.connection_cls(self.conf, self.url, purpose)
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def empty(self):
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for item in self.iter_free():
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item.close()
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