98 lines
3.6 KiB
Python
98 lines
3.6 KiB
Python
# Copyright 2016 Tesora, 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.
|
|
#
|
|
|
|
from oslo_log import log as logging
|
|
from oslo_utils import encodeutils
|
|
import stevedore
|
|
|
|
from trove.common import base_exception as exception
|
|
from trove.common import cfg
|
|
from trove.common.i18n import _
|
|
|
|
LOG = logging.getLogger(__name__)
|
|
CONF = cfg.CONF
|
|
|
|
|
|
class ModuleDriverManager(object):
|
|
|
|
MODULE_DRIVER_NAMESPACE = 'trove.guestagent.module.drivers'
|
|
|
|
def __init__(self):
|
|
LOG.info('Initializing module driver manager.')
|
|
|
|
self._drivers = {}
|
|
self._module_types = [mt.lower() for mt in CONF.module_types]
|
|
|
|
self._load_drivers()
|
|
|
|
def _load_drivers(self):
|
|
manager = stevedore.enabled.EnabledExtensionManager(
|
|
namespace=self.MODULE_DRIVER_NAMESPACE,
|
|
check_func=self._check_extension,
|
|
invoke_on_load=True,
|
|
invoke_kwds={})
|
|
try:
|
|
manager.map(self.add_driver_extension)
|
|
except stevedore.exception.NoMatches:
|
|
LOG.info("No module drivers loaded")
|
|
|
|
def _check_extension(self, extension):
|
|
"""Checks for required methods in driver objects."""
|
|
driver = extension.obj
|
|
supported = False
|
|
try:
|
|
LOG.info('Loading Module driver: %s', driver.get_type())
|
|
if driver.get_type() != driver.get_type().lower():
|
|
raise AttributeError(_("Driver 'type' must be lower-case"))
|
|
LOG.debug(' description: %s', driver.get_description())
|
|
LOG.debug(' updated : %s', driver.get_updated())
|
|
required_attrs = ['apply', 'remove']
|
|
for attr in required_attrs:
|
|
if not hasattr(driver, attr):
|
|
raise AttributeError(
|
|
_("Driver '%(type)s' missing attribute: %(attr)s")
|
|
% {'type': driver.get_type(), 'attr': attr})
|
|
if driver.get_type() in self._module_types:
|
|
supported = True
|
|
else:
|
|
LOG.info("Driver '%s' not supported, skipping",
|
|
driver.get_type())
|
|
except AttributeError as ex:
|
|
LOG.exception("Exception loading module driver: %s",
|
|
encodeutils.exception_to_unicode(ex))
|
|
|
|
return supported
|
|
|
|
def add_driver_extension(self, extension):
|
|
# Add a module driver from the extension.
|
|
# If the stevedore manager is changed to one that doesn't
|
|
# check the extension driver, then it should be done manually here
|
|
# by calling self._check_extension(extension)
|
|
driver = extension.obj
|
|
driver_type = driver.get_type()
|
|
LOG.info('Loaded module driver: %s', driver_type)
|
|
|
|
if driver_type in self._drivers:
|
|
raise exception.Error(_("Found duplicate driver: %s") %
|
|
driver_type)
|
|
self._drivers[driver_type] = driver
|
|
|
|
def get_driver(self, driver_type):
|
|
found = None
|
|
if driver_type in self._drivers:
|
|
found = self._drivers[driver_type]
|
|
return found
|