neutron/quantum/manager.py
Brad Hall 6a08320031 Second round of packaging changes
This change condenses the directory structure to something more similar to
what we had before while producing similar packages.

It also introduces version.py which allows us to get the version from git tags
(or a fallback version if not available).

Fixes lp bug 889336
Fixes lp bug 888795

Change-Id: I86136bd9dbabb5eb1f8366ed665ed9b54f695124
2011-11-28 10:33:52 -08:00

89 lines
3.0 KiB
Python

# vim: tabstop=4 shiftwidth=4 softtabstop=4
# Copyright 2011 Nicira Networks, Inc
# All Rights Reserved.
#
# 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.
# @author: Somik Behera, Nicira Networks, Inc.
"""
Quantum's Manager class is responsible for parsing a config file and
instantiating the correct plugin that concretely implement quantum_plugin_base
class.
The caller should make sure that QuantumManager is a singleton.
"""
import gettext
import logging
import os
gettext.install('quantum', unicode=1)
from quantum.common import utils
from quantum.common.config import find_config_file
from quantum.common.exceptions import ClassNotFound
from quantum_plugin_base import QuantumPluginBase
LOG = logging.getLogger('quantum.manager')
CONFIG_FILE = "plugins.ini"
LOG = logging.getLogger('quantum.manager')
def find_config(basepath):
for root, dirs, files in os.walk(basepath):
if CONFIG_FILE in files:
return os.path.join(root, CONFIG_FILE)
return None
class QuantumManager(object):
_instance = None
def __init__(self, options=None, config_file=None):
# If no options have been provided, create an empty dict
if not options:
options = {}
if config_file:
config_file = [config_file]
self.configuration_file = find_config_file(options, config_file,
CONFIG_FILE)
if not 'plugin_provider' in options:
options['plugin_provider'] = \
utils.get_plugin_from_config(self.configuration_file)
LOG.debug("Plugin location:%s", options['plugin_provider'])
# If the plugin can't be found let them know gracefully
try:
plugin_klass = utils.import_class(options['plugin_provider'])
except ClassNotFound:
raise Exception("Plugin not found. You can install a " \
"plugin with: pip install <plugin-name>\n" \
"Example: pip install quantum-sample-plugin")
if not issubclass(plugin_klass, QuantumPluginBase):
raise Exception("Configured Quantum plug-in " \
"didn't pass compatibility test")
else:
LOG.debug("Successfully imported Quantum plug-in." \
"All compatibility tests passed")
self.plugin = plugin_klass()
@classmethod
def get_plugin(cls, options=None, config_file=None):
if cls._instance is None:
cls._instance = cls(options, config_file)
return cls._instance.plugin