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OpenStack Study: memcache.py**** CubicPower OpenStack Study ****
# Copyright (c) 2010-2012 OpenStack Foundation # # 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 os from ConfigParser import ConfigParser, NoSectionError, NoOptionError from swift.common.memcached import MemcacheRing
**** CubicPower OpenStack Study **** class MemcacheMiddleware(object): """ Caching middleware that manages caching in swift. """
**** CubicPower OpenStack Study **** def __init__(self, app, conf): self.app = app self.memcache_servers = conf.get('memcache_servers') serialization_format = conf.get('memcache_serialization_support') try: # Originally, while we documented using memcache_max_connections # we only accepted max_connections max_conns = int(conf.get('memcache_max_connections', conf.get('max_connections', 0))) except ValueError: max_conns = 0 if (not self.memcache_servers or serialization_format is None or max_conns <= 0): path = os.path.join(conf.get('swift_dir', '/etc/swift'), 'memcache.conf') memcache_conf = ConfigParser() if memcache_conf.read(path): if not self.memcache_servers: try: self.memcache_servers = \ memcache_conf.get('memcache', 'memcache_servers') except (NoSectionError, NoOptionError): pass if serialization_format is None: try: serialization_format = \ memcache_conf.get('memcache', 'memcache_serialization_support') except (NoSectionError, NoOptionError): pass if max_conns <= 0: try: new_max_conns = \ memcache_conf.get('memcache', 'memcache_max_connections') max_conns = int(new_max_conns) except (NoSectionError, NoOptionError, ValueError): pass if not self.memcache_servers: self.memcache_servers = '127.0.0.1:11211' if max_conns <= 0: max_conns = 2 if serialization_format is None: serialization_format = 2 else: serialization_format = int(serialization_format) self.memcache = MemcacheRing( [s.strip() for s in self.memcache_servers.split(',') if s.strip()], allow_pickle=(serialization_format == 0), allow_unpickle=(serialization_format <= 1), max_conns=max_conns)
**** CubicPower OpenStack Study **** def __call__(self, env, start_response): env['swift.cache'] = self.memcache return self.app(env, start_response) def filter_factory(global_conf, **local_conf): conf = global_conf.copy() conf.update(local_conf)
**** CubicPower OpenStack Study **** def filter_factory(global_conf, **local_conf): conf = global_conf.copy() conf.update(local_conf)
**** CubicPower OpenStack Study **** def cache_filter(app): return MemcacheMiddleware(app, conf) return cache_filter
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