104 lines
2.7 KiB
Python
104 lines
2.7 KiB
Python
# Copyright 2012 Bouvet ASA
|
|
#
|
|
# Author: Endre Karlson <endre.karlson@bouvet.no>
|
|
#
|
|
# 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 abc
|
|
|
|
import six
|
|
from stevedore import driver
|
|
from stevedore import enabled
|
|
from oslo_config import cfg
|
|
from oslo_log import log as logging
|
|
|
|
|
|
LOG = logging.getLogger(__name__)
|
|
CONF = cfg.CONF
|
|
|
|
|
|
@six.add_metaclass(abc.ABCMeta)
|
|
class Plugin(object):
|
|
__plugin_ns__ = None
|
|
|
|
__plugin_name__ = None
|
|
__plugin_type__ = None
|
|
|
|
def __init__(self):
|
|
self.name = self.get_canonical_name()
|
|
LOG.debug("Loaded plugin %s", self.name)
|
|
|
|
@classmethod
|
|
def get_canonical_name(cls):
|
|
"""
|
|
Return the plugin name
|
|
"""
|
|
type_ = cls.get_plugin_type()
|
|
name = cls.get_plugin_name()
|
|
return "%s:%s" % (type_, name)
|
|
|
|
@classmethod
|
|
def get_plugin_name(cls):
|
|
return cls.__plugin_name__
|
|
|
|
@classmethod
|
|
def get_plugin_type(cls):
|
|
return cls.__plugin_type__
|
|
|
|
|
|
class DriverPlugin(Plugin):
|
|
"""
|
|
A Driver plugin is a singleton, where only a single driver will loaded
|
|
at a time.
|
|
|
|
For example: Storage implementations (SQLAlchemy)
|
|
"""
|
|
|
|
@classmethod
|
|
def get_driver(cls, name):
|
|
"""Load a single driver"""
|
|
|
|
LOG.debug('Looking for driver %s in %s', name, cls.__plugin_ns__)
|
|
|
|
mgr = driver.DriverManager(cls.__plugin_ns__, name)
|
|
|
|
return mgr.driver
|
|
|
|
|
|
class ExtensionPlugin(Plugin):
|
|
"""
|
|
Extension plugins are loaded as a group, where multiple extensions will
|
|
be loaded and used at the same time.
|
|
|
|
For example: Designate Sink handlers
|
|
"""
|
|
|
|
@classmethod
|
|
def get_extensions(cls, enabled_extensions=None):
|
|
"""Load a series of extensions"""
|
|
|
|
LOG.debug('Looking for extensions in %s' % cls.__plugin_ns__)
|
|
|
|
def _check_func(ext):
|
|
if enabled_extensions is None:
|
|
# All extensions are enabled by default, if no specific list
|
|
# is specified
|
|
return True
|
|
|
|
return ext.plugin.get_plugin_name() in enabled_extensions
|
|
|
|
mgr = enabled.EnabledExtensionManager(
|
|
cls.__plugin_ns__, check_func=_check_func,
|
|
propagate_map_exceptions=True)
|
|
|
|
return [e.plugin for e in mgr]
|