d440972d10
Instead of calling the callback while holding a write lock (a recipe for deadlock) call the callbacks after we pop all the values to avoid any potential for deadlock. Change-Id: Idb4275d8f07d60e2ed83c0987b6c7354a09c8a71
59 lines
1.8 KiB
Python
59 lines
1.8 KiB
Python
# -*- coding: utf-8 -*-
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# Copyright (C) 2014 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 logging
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import six
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from taskflow.utils import lock_utils as lu
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LOG = logging.getLogger(__name__)
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class Cache(object):
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"""Represents thread-safe cache."""
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def __init__(self):
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self._data = {}
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self._lock = lu.ReaderWriterLock()
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def get(self, key):
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"""Retrieve a value from the cache."""
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with self._lock.read_lock():
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return self._data.get(key)
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def set(self, key, value):
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"""Set a value in the cache."""
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with self._lock.write_lock():
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self._data[key] = value
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LOG.debug("Cache updated. Capacity: %s", len(self._data))
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def delete(self, key):
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"""Delete a value from the cache."""
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with self._lock.write_lock():
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self._data.pop(key, None)
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def cleanup(self, on_expired_callback=None):
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"""Delete out-dated values from the cache."""
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with self._lock.write_lock():
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expired_values = [(k, v) for k, v in six.iteritems(self._data)
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if v.expired]
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for (k, _v) in expired_values:
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self._data.pop(k, None)
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if on_expired_callback:
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for (_k, v) in expired_values:
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on_expired_callback(v)
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