ea191cacb1
Due to the way caching is disabled the SHOULD_CACHE_FN() is used to determine if new values are stored in the cache backend, and is only called when the regeneration is required. If dogpile is configured to connect to a memcache, redis, etc to store data it is possible with caching disabled to still pull values from the cache (SHOULD_CACHE_FN has no bearing on reads). The issue described only impacts the use of the memoization decorator. This change forces dogpile to use the null backend if caching is globally disabled to ensure no data is read from the external cache. This will not affect subsystem disabling of cache. Even with cache disabled but reads coming from the external cache, there stale data is not a concern as invalidates will still be processed and the data from the backend will eventually timeout in most cases. Change-Id: I845b6cc18faa2be516676eeacc574473ca84c995 Closes-Bug: #1567413
125 lines
6.1 KiB
Python
125 lines
6.1 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): the dogpile.cache.memory acceptable in devstack
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# and other such single-process/thread deployments. Running
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# dogpile.cache.memory in any other configuration has the same pitfalls
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# as the KVS token backend. 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 keystone default caching
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# backend.
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cfg.StrOpt('backend', default=_DEFAULT_BACKEND,
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help='Dogpile.cache backend module. It is recommended '
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'that Memcache with pooling '
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'(oslo_cache.memcache_pool) or Redis '
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'(dogpile.cache.redis) be used in production '
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'deployments. Small workloads (single process) '
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'like devstack can use the dogpile.cache.memory '
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'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.memcache and oslo_cache.memcache_pool'
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' backends only).'),
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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.IntOpt('memcache_socket_timeout',
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default=3,
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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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