0e1c6f5612
Some environments with ipv6 used to connect with memcached servers faced issues by omitting to prefix the host with the address family to use. Indeed libraries like python-memcached waiting for a prefix to initialize the socket with the right address family. If the prefix isn't given and that the host refer or bind an ipv6 then the socket is initialized with an address family which correspond to an IPv4 and the connection doesn't work properly. Openstack's puppet libraries already fixed that by introducing new feature to automatically prefix the address if needed [1][2]. Anyway it could be worth to add more documentation on oslo.cache to give more information to customers and avoid similar issues. These changes aim to provide this documentation. [1] https://review.opendev.org/#/q/status:merged+branch:master+topic:memcached-inet6-prefix [2] https://review.opendev.org/#/c/661136/ Change-Id: I5e0b4818300348efe4625500792d9161281ed45a
143 lines
7.2 KiB
Python
143 lines
7.2 KiB
Python
# Copyright 2012 OpenStack Foundation
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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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from oslo_config import cfg
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_DEFAULT_BACKEND = 'dogpile.cache.null'
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FILE_OPTIONS = {
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'cache': [
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cfg.StrOpt('config_prefix', default='cache.oslo',
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help='Prefix for building the configuration dictionary '
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'for the cache region. This should not need to be '
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'changed unless there is another dogpile.cache '
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'region with the same configuration name.'),
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cfg.IntOpt('expiration_time', default=600,
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help='Default TTL, in seconds, for any cached item in '
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'the dogpile.cache region. This applies to any '
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'cached method that doesn\'t have an explicit '
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'cache expiration time defined for it.'),
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# NOTE(morganfainberg): It is recommended that either Redis or
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# Memcached are used as the dogpile backend for real workloads. To
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# prevent issues with the memory cache ending up in "production"
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# unintentionally, we register a no-op as the default caching backend.
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cfg.StrOpt('backend', default=_DEFAULT_BACKEND,
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choices=['oslo_cache.memcache_pool',
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'oslo_cache.dict',
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'oslo_cache.mongo',
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'oslo_cache.etcd3gw',
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'dogpile.cache.memcached',
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'dogpile.cache.pylibmc',
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'dogpile.cache.bmemcached',
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'dogpile.cache.dbm',
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'dogpile.cache.redis',
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'dogpile.cache.memory',
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'dogpile.cache.memory_pickle',
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'dogpile.cache.null'],
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help='Cache backend module. For eventlet-based or '
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'environments with hundreds of threaded servers, Memcache '
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'with pooling (oslo_cache.memcache_pool) is recommended. '
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'For environments with less than 100 threaded servers, '
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'Memcached (dogpile.cache.memcached) or Redis '
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'(dogpile.cache.redis) is recommended. Test environments '
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'with a single instance of the server can use the '
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'dogpile.cache.memory backend.'),
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cfg.MultiStrOpt('backend_argument', default=[], secret=True,
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help='Arguments supplied to the backend module. '
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'Specify this option once per argument to be '
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'passed to the dogpile.cache backend. Example '
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'format: "<argname>:<value>".'),
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cfg.ListOpt('proxies', default=[],
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help='Proxy classes to import that will affect the way '
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'the dogpile.cache backend functions. See the '
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'dogpile.cache documentation on '
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'changing-backend-behavior.'),
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cfg.BoolOpt('enabled', default=False,
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help='Global toggle for caching.'),
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cfg.BoolOpt('debug_cache_backend', default=False,
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help='Extra debugging from the cache backend (cache '
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'keys, get/set/delete/etc calls). This is only '
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'really useful if you need to see the specific '
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'cache-backend get/set/delete calls with the '
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'keys/values. Typically this should be left set '
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'to false.'),
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cfg.ListOpt('memcache_servers', default=['localhost:11211'],
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help='Memcache servers in the format of "host:port". '
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'(dogpile.cache.memcached and '
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'oslo_cache.memcache_pool backends only). '
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'If a given host refer to an IPv6 or a given domain '
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'refer to IPv6 then you should prefix the given '
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'address with the address family (``inet6``) '
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'(e.g ``inet6[::1]:11211``, '
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'``inet6:[fd12:3456:789a:1::1]:11211``, '
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'``inet6:[controller-0.internalapi]:11211``). '
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'If the address family is not given then default '
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'address family used will be ``inet`` which '
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'correspond to IPv4'),
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cfg.IntOpt('memcache_dead_retry',
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default=5 * 60,
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help='Number of seconds memcached server is considered dead'
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' before it is tried again. (dogpile.cache.memcache and'
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' oslo_cache.memcache_pool backends only).'),
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cfg.FloatOpt('memcache_socket_timeout',
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default=1.0,
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help='Timeout in seconds for every call to a server.'
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' (dogpile.cache.memcache and oslo_cache.memcache_pool'
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' backends only).'),
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cfg.IntOpt('memcache_pool_maxsize',
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default=10,
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help='Max total number of open connections to every'
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' memcached server. (oslo_cache.memcache_pool backend'
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' only).'),
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cfg.IntOpt('memcache_pool_unused_timeout',
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default=60,
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help='Number of seconds a connection to memcached is held'
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' unused in the pool before it is closed.'
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' (oslo_cache.memcache_pool backend only).'),
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cfg.IntOpt('memcache_pool_connection_get_timeout',
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default=10,
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help='Number of seconds that an operation will wait to get '
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'a memcache client connection.'),
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],
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}
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def configure(conf):
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for section in FILE_OPTIONS:
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for option in FILE_OPTIONS[section]:
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conf.register_opt(option, group=section)
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def list_opts():
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"""Return a list of oslo_config options.
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The returned list includes all oslo_config options which are registered as
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the "FILE_OPTIONS".
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Each object in the list is a two element tuple. The first element of
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each tuple is the name of the group under which the list of options in the
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second element will be registered. A group name of None corresponds to the
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[DEFAULT] group in config files.
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This function is also discoverable via the 'oslo_config.opts' entry point
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under the 'oslo_cache.config.opts' namespace.
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The purpose of this is to allow tools like the Oslo sample config file
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generator to discover the options exposed to users by this library.
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:returns: a list of (group_name, opts) tuples
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"""
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return list(FILE_OPTIONS.items())
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