98 lines
2.9 KiB
Python
98 lines
2.9 KiB
Python
# Copyright 2010 United States Government as represented by the
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# Administrator of the National Aeronautics and Space Administration.
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# 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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"""Super simple fake memcache client."""
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import copy
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from oslo_config import cfg
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from oslo_utils import timeutils
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memcache_opts = [
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cfg.ListOpt('memcached_servers',
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help='Memcached servers or None for in process cache.'),
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]
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CONF = cfg.CONF
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CONF.register_opts(memcache_opts)
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def list_opts():
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"""Entry point for oslo-config-generator."""
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return [(None, copy.deepcopy(memcache_opts))]
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def get_client(memcached_servers=None):
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client_cls = Client
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if not memcached_servers:
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memcached_servers = CONF.memcached_servers
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if memcached_servers:
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import memcache
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client_cls = memcache.Client
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return client_cls(memcached_servers, debug=0)
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class Client(object):
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"""Replicates a tiny subset of memcached client interface."""
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def __init__(self, *args, **kwargs):
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"""Ignores the passed in args."""
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self.cache = {}
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def get(self, key):
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"""Retrieves the value for a key or None.
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This expunges expired keys during each get.
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"""
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now = timeutils.utcnow_ts()
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for k in list(self.cache):
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(timeout, _value) = self.cache[k]
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if timeout and now >= timeout:
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del self.cache[k]
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return self.cache.get(key, (0, None))[1]
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def set(self, key, value, time=0, min_compress_len=0):
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"""Sets the value for a key."""
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timeout = 0
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if time != 0:
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timeout = timeutils.utcnow_ts() + time
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self.cache[key] = (timeout, value)
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return True
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def add(self, key, value, time=0, min_compress_len=0):
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"""Sets the value for a key if it doesn't exist."""
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if self.get(key) is not None:
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return False
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return self.set(key, value, time, min_compress_len)
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def incr(self, key, delta=1):
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"""Increments the value for a key."""
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value = self.get(key)
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if value is None:
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return None
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new_value = int(value) + delta
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self.cache[key] = (self.cache[key][0], str(new_value))
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return new_value
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def delete(self, key, time=0):
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"""Deletes the value associated with a key."""
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if key in self.cache:
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del self.cache[key]
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