Source code for watcher.common.loader.default

# -*- encoding: utf-8 -*-
# Copyright (c) 2016 b<>com
#
# 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.

from __future__ import unicode_literals

from oslo_config import cfg
from oslo_log import log
from stevedore import driver as drivermanager
from stevedore import extension as extensionmanager

from watcher.common import exception
from watcher.common.loader import base
from watcher.common import utils

LOG = log.getLogger(__name__)


[docs]class DefaultLoader(base.BaseLoader): def __init__(self, namespace, conf=cfg.CONF): """Entry point loader for Watcher using Stevedore :param namespace: namespace of the entry point(s) to load or list :type namespace: str :param conf: ConfigOpts instance, defaults to cfg.CONF """ super(DefaultLoader, self).__init__() self.namespace = namespace self.conf = conf
[docs] def load(self, name, **kwargs): try: LOG.debug("Loading in namespace %s => %s ", self.namespace, name) driver_manager = drivermanager.DriverManager( namespace=self.namespace, name=name, invoke_on_load=False, ) driver_cls = driver_manager.driver config = self._load_plugin_config(name, driver_cls) driver = driver_cls(config, **kwargs) except Exception as exc: LOG.exception(exc) raise exception.LoadingError(name=name) return driver
def _reload_config(self): self.conf(default_config_files=self.conf.default_config_files)
[docs] def get_entry_name(self, name): return ".".join([self.namespace, name])
def _load_plugin_config(self, name, driver_cls): """Load the config of the plugin""" config = utils.Struct() config_opts = driver_cls.get_config_opts() if not config_opts: return config group_name = self.get_entry_name(name) self.conf.register_opts(config_opts, group=group_name) # Finalise the opt import by re-checking the configuration # against the provided config files self._reload_config() config_group = self.conf.get(group_name) if not config_group: raise exception.LoadingError(name=name) config.update({ name: value for name, value in config_group.items() }) return config
[docs] def list_available(self): extension_manager = extensionmanager.ExtensionManager( namespace=self.namespace) return {ext.name: ext.plugin for ext in extension_manager.extensions}