OpenStack library for messaging
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# Copyright 2014 Rackspace Hosting
# 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.
import fnmatch
import logging
import six
from stevedore import dispatch
import yaml
from oslo.config import cfg
from oslo.messaging.notify import notifier
from oslo.messaging.openstack.common.gettextutils import _ # noqa
LOG = logging.getLogger(__name__)
router_config = cfg.StrOpt('routing_notifier_config', default='',
help='RoutingNotifier configuration file location.')
CONF = cfg.CONF
CONF.register_opt(router_config)
class RoutingDriver(notifier._Driver):
NOTIFIER_PLUGIN_NAMESPACE = 'oslo.messaging.notify.drivers'
plugin_manager = None
routing_groups = None # The routing groups from the config file.
used_drivers = None # Used driver names, extracted from config file.
def _should_load_plugin(self, ext, *args, **kwargs):
# Hack to keep stevedore from circular importing since these
# endpoints are used for different purposes.
if ext.name == 'routing':
return False
return ext.name in self.used_drivers
def _get_notifier_config_file(self, filename):
"""Broken out for testing."""
return file(filename, 'r')
def _load_notifiers(self):
"""One-time load of notifier config file."""
self.routing_groups = {}
self.used_drivers = set()
filename = CONF.routing_notifier_config
if not filename:
return
# Infer which drivers are used from the config file.
self.routing_groups = yaml.load(
self._get_notifier_config_file(filename))
if not self.routing_groups:
self.routing_groups = {} # In case we got None from load()
return
for group in self.routing_groups.values():
self.used_drivers.update(group.keys())
LOG.debug('loading notifiers from %s', self.NOTIFIER_PLUGIN_NAMESPACE)
self.plugin_manager = dispatch.DispatchExtensionManager(
namespace=self.NOTIFIER_PLUGIN_NAMESPACE,
check_func=self._should_load_plugin,
invoke_on_load=True,
invoke_args=None)
if not list(self.plugin_manager):
LOG.warning(_("Failed to load any notifiers for %s"),
self.NOTIFIER_PLUGIN_NAMESPACE)
def _get_drivers_for_message(self, group, event_type, priority):
"""Which drivers should be called for this event_type
or priority.
"""
accepted_drivers = set()
for driver, rules in six.iteritems(group):
checks = []
for key, patterns in six.iteritems(rules):
if key == 'accepted_events':
c = [fnmatch.fnmatch(event_type, p)
for p in patterns]
checks.append(any(c))
if key == 'accepted_priorities':
c = [fnmatch.fnmatch(priority, p.lower())
for p in patterns]
checks.append(any(c))
if all(checks):
accepted_drivers.add(driver)
return list(accepted_drivers)
def _filter_func(self, ext, context, message, priority, retry,
accepted_drivers):
"""True/False if the driver should be called for this message.
"""
# context is unused here, but passed in by map()
return ext.name in accepted_drivers
def _call_notify(self, ext, context, message, priority, retry,
accepted_drivers):
"""Emit the notification.
"""
# accepted_drivers is passed in as a result of the map() function
LOG.info(_("Routing '%(event)s' notification to '%(driver)s' driver"),
{'event': message.get('event_type'), 'driver': ext.name})
ext.obj.notify(context, message, priority, retry)
def notify(self, context, message, priority, retry):
if not self.plugin_manager:
self._load_notifiers()
# Fail if these aren't present ...
event_type = message['event_type']
accepted_drivers = set()
for group in self.routing_groups.values():
accepted_drivers.update(
self._get_drivers_for_message(group, event_type,
priority.lower()))
self.plugin_manager.map(self._filter_func, self._call_notify, context,
message, priority, retry,
list(accepted_drivers))