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# 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 eventlet.green import ssl
from six.moves.configparser import ConfigParser, NoSectionError, NoOptionError
from swift.common.memcached import (
MemcacheRing, CONN_TIMEOUT, POOL_TIMEOUT, IO_TIMEOUT, TRY_COUNT,
ERROR_LIMIT_COUNT, ERROR_LIMIT_TIME, DEFAULT_ITEM_SIZE_WARNING_THRESHOLD)
from swift.common.utils import get_logger, config_true_value
class MemcacheMiddleware(object):
"""
Caching middleware that manages caching in swift.
"""
def __init__(self, app, conf):
self.app = app
self.logger = get_logger(conf, log_route='memcache')
self.memcache_servers = conf.get('memcache_servers')
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
memcache_options = {}
if (not self.memcache_servers
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 memcache.conf exists we'll start with those base options
try:
memcache_options = dict(memcache_conf.items('memcache'))
except NoSectionError:
pass
if not self.memcache_servers:
try:
self.memcache_servers = \
memcache_conf.get('memcache', 'memcache_servers')
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
# while memcache.conf options are the base for the memcache
# middleware, if you set the same option also in the filter
# section of the proxy config it is more specific.
memcache_options.update(conf)
connect_timeout = float(memcache_options.get(
'connect_timeout', CONN_TIMEOUT))
pool_timeout = float(memcache_options.get(
'pool_timeout', POOL_TIMEOUT))
tries = int(memcache_options.get('tries', TRY_COUNT))
io_timeout = float(memcache_options.get('io_timeout', IO_TIMEOUT))
if config_true_value(memcache_options.get('tls_enabled', 'false')):
tls_cafile = memcache_options.get('tls_cafile')
tls_certfile = memcache_options.get('tls_certfile')
tls_keyfile = memcache_options.get('tls_keyfile')
self.tls_context = ssl.create_default_context(
cafile=tls_cafile)
if tls_certfile:
self.tls_context.load_cert_chain(tls_certfile,
tls_keyfile)
else:
self.tls_context = None
error_suppression_interval = float(memcache_options.get(
'error_suppression_interval', ERROR_LIMIT_TIME))
error_suppression_limit = float(memcache_options.get(
'error_suppression_limit', ERROR_LIMIT_COUNT))
item_size_warning_threshold = int(memcache_options.get(
'item_size_warning_threshold',
DEFAULT_ITEM_SIZE_WARNING_THRESHOLD))
if not self.memcache_servers:
self.memcache_servers = '127.0.0.1:11211'
if max_conns <= 0:
max_conns = 2
self.memcache = MemcacheRing(
[s.strip() for s in self.memcache_servers.split(',') if s.strip()],
connect_timeout=connect_timeout,
pool_timeout=pool_timeout,
tries=tries,
io_timeout=io_timeout,
max_conns=max_conns,
tls_context=self.tls_context,
logger=self.logger,
error_limit_count=error_suppression_limit,
error_limit_time=error_suppression_interval,
error_limit_duration=error_suppression_interval,
item_size_warning_threshold=item_size_warning_threshold)
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)
def cache_filter(app):
return MemcacheMiddleware(app, conf)
return cache_filter
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