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