/usr/lib/python2.7/dist-packages/oslo_messaging/_drivers/zmq_driver/server/zmq_ttl_cache.py is in python-oslo.messaging 5.10.0-2.
This file is owned by root:root, with mode 0o644.
The actual contents of the file can be viewed below.
1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60 61 62 63 64 65 66 67 68 69 70 71 72 73 74 75 76 77 78 79 | # Copyright 2016 Mirantis, Inc.
#
# Licensed under the Apache License, Version 2.0 (the "License"); you may
# not use this file except in compliance with the License. You may obtain
# a copy of the License at
#
# http://www.apache.org/licenses/LICENSE-2.0
#
# Unless required by applicable law or agreed to in writing, software
# distributed under the License is distributed on an "AS IS" BASIS, WITHOUT
# WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. See the
# License for the specific language governing permissions and limitations
# under the License.
import threading
import time
import six
from oslo_messaging._drivers.zmq_driver import zmq_async
zmq = zmq_async.import_zmq()
class TTLCache(object):
def __init__(self, ttl=None):
self._lock = threading.Lock()
self._expiration_times = {}
self._executor = None
if not (ttl is None or isinstance(ttl, (int, float))):
raise ValueError('ttl must be None or a number')
# no (i.e. infinite) ttl
if ttl is None or ttl <= 0:
ttl = float('inf')
else:
self._executor = zmq_async.get_executor(self._update_cache)
self._ttl = ttl
if self._executor:
self._executor.execute()
@staticmethod
def _is_expired(expiration_time, current_time):
return expiration_time <= current_time
def add(self, item):
with self._lock:
self._expiration_times[item] = time.time() + self._ttl
def discard(self, item):
with self._lock:
self._expiration_times.pop(item, None)
def __contains__(self, item):
with self._lock:
expiration_time = self._expiration_times.get(item)
if expiration_time is None:
return False
if self._is_expired(expiration_time, time.time()):
self._expiration_times.pop(item)
return False
return True
def _update_cache(self):
with self._lock:
current_time = time.time()
self._expiration_times = \
{item: expiration_time for
item, expiration_time in six.iteritems(self._expiration_times)
if not self._is_expired(expiration_time, current_time)}
time.sleep(self._ttl)
def cleanup(self):
if self._executor:
self._executor.stop()
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