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# Copyright 2013 Red Hat, Inc.
#
# 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.
"""Cache library.
Supported configuration options:
`default_backend`: Name of the cache backend to use.
`key_namespace`: Namespace under which keys will be created.
"""
########################################################################
#
# THIS MODULE IS DEPRECATED
#
# Please refer to
# https://etherpad.openstack.org/p/kilo-oslo-library-proposals for
# the discussion leading to this deprecation.
#
# We recommend helping with the new oslo.cache library being created
# as a wrapper for dogpile.
#
########################################################################
from six.moves.urllib import parse
from stevedore import driver
def _get_oslo_configs():
"""Returns the oslo config options to register."""
# NOTE(flaper87): Oslo config should be
# optional. Instead of doing try / except
# at the top of this file, lets import cfg
# here and assume that the caller of this
# function already took care of this dependency.
from oslo_config import cfg
return [
cfg.StrOpt('cache_url', default='memory://',
help='URL to connect to the cache back end.')
]
def register_oslo_configs(conf):
"""Registers a cache configuration options
:params conf: Config object.
:type conf: `cfg.ConfigOptions`
"""
conf.register_opts(_get_oslo_configs())
def get_cache(url='memory://'):
"""Loads the cache backend
This function loads the cache backend
specified in the given configuration.
:param conf: Configuration instance to use
"""
parsed = parse.urlparse(url)
backend = parsed.scheme
query = parsed.query
# NOTE(flaper87): We need the following hack
# for python versions < 2.7.5. Previous versions
# of python parsed query params just for 'known'
# schemes. This was changed in this patch:
# http://hg.python.org/cpython/rev/79e6ff3d9afd
if not query and '?' in parsed.path:
query = parsed.path.split('?', 1)[-1]
parameters = parse.parse_qsl(query)
kwargs = {'options': dict(parameters)}
mgr = driver.DriverManager('openstack.common.cache.backends', backend,
invoke_on_load=True,
invoke_args=[parsed],
invoke_kwds=kwargs)
return mgr.driver
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