137 lines
4.5 KiB
Python
137 lines
4.5 KiB
Python
# 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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import itertools
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import six
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from oslo_log import log as logging
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from bilean.common.i18n import _LI
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from bilean.common.i18n import _LW
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LOG = logging.getLogger(__name__)
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class PluginInfo(object):
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'''Base mapping of plugin type to implementation.'''
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def __new__(cls, registry, name, plugin, **kwargs):
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'''Create a new PluginInfo of the appropriate class.
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Placeholder for class hierarchy extensibility
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'''
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return super(PluginInfo, cls).__new__(cls)
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def __init__(self, registry, name, plugin):
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self.registry = registry
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self.name = name
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self.plugin = plugin
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self.user_provided = True
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def __eq__(self, other):
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if other is None:
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return False
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return (self.name == other.name and
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self.plugin == other.plugin and
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self.user_provided == other.user_provided)
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def __ne__(self, other):
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return not self.__eq__(other)
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def __lt__(self, other):
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if self.user_provided != other.user_provided:
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# user provided ones must be sorted above system ones.
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return self.user_provided > other.user_provided
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if len(self.name) != len(other.name):
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# more specific (longer) name must be sorted above system ones.
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return len(self.name) > len(other.name)
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return self.name < other.name
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def __gt__(self, other):
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return other.__lt__(self)
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def __str__(self):
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return '[Plugin](User:%s) %s -> %s' % (self.user_provided,
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self.name, str(self.plugin))
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class Registry(object):
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'''A registry for managing rule classes.'''
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def __init__(self, registry_name, global_registry=None):
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self.registry_name = registry_name
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self._registry = {}
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self.is_global = False if global_registry else True
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self.global_registry = global_registry
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def _register_info(self, name, info):
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'''place the new info in the correct location in the registry.
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:param path: a string of plugin name.
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:param info: reference to a PluginInfo data structure, deregister a
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PluginInfo if specified as None.
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'''
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registry = self._registry
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if info is None:
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# delete this entry.
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LOG.warn(_LW('Removing %(item)s from registry'), {'item': name})
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registry.pop(name, None)
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return
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if name in registry and isinstance(registry[name], PluginInfo):
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if registry[name] == info:
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return
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details = {
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'name': name,
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'old': str(registry[name].plugin),
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'new': str(info.plugin)
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}
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LOG.warn(_LW('Changing %(name)s from %(old)s to %(new)s'), details)
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else:
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LOG.info(_LI('Registering %(name)s -> %(value)s'), {
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'name': name, 'value': str(info.plugin)})
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info.user_provided = not self.is_global
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registry[name] = info
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def register_plugin(self, name, plugin):
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pi = PluginInfo(self, name, plugin)
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self._register_info(name, pi)
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def load(self, json_snippet):
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for k, v in iter(json_snippet.items()):
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if v is None:
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self._register_info(k, None)
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else:
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self.register_plugin(k, v)
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def iterable_by(self, name):
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plugin = self._registry.get(name)
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if plugin:
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yield plugin
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def get_plugin(self, name):
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giter = []
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if not self.is_global:
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giter = self.global_registry.iterable_by(name)
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matches = itertools.chain(self.iterable_by(name), giter)
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infoes = sorted(matches)
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return infoes[0].plugin if infoes else None
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def as_dict(self):
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return dict((k, v.plugin) for k, v in self._registry.items())
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def get_types(self):
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'''Return a list of valid plugin types.'''
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return [{'name': name} for name in six.iterkeys(self._registry)]
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