# Copyright 2011 OpenStack Foundation. # All Rights Reserved. # Copyright 2013 Red Hat, Inc. # # 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 abc import logging from oslo.config import cfg import six from stevedore import named from oslo.messaging.openstack.common import timeutils from oslo.messaging.openstack.common import uuidutils from oslo.messaging import serializer as msg_serializer _notifier_opts = [ cfg.MultiStrOpt('notification_driver', default=[], help='Driver or drivers to handle sending notifications'), cfg.ListOpt('notification_topics', default=['notifications', ], deprecated_name='topics', deprecated_group='rpc_notifier2', help='AMQP topic used for OpenStack notifications'), ] _LOG = logging.getLogger(__name__) @six.add_metaclass(abc.ABCMeta) class _Driver(object): def __init__(self, conf, topics, transport): self.conf = conf self.topics = topics self.transport = transport @abc.abstractmethod def notify(self, ctxt, msg, priority): pass class Notifier(object): """Send notification messages. The Notifier class is used for sending notification messages over a messaging transport or other means. Notification messages follow the following format:: {'message_id': str(uuid.uuid4()), 'publisher_id': 'compute.host1', 'timestamp': timeutils.utcnow(), 'priority': 'WARN', 'event_type': 'compute.create_instance', 'payload': {'instance_id': 12, ... }} A Notifier object can be instantiated with a transport object and a publisher ID: notifier = notifier.Notifier(get_transport(CONF), 'compute') and notifications are sent via drivers chosen with the notification_driver config option and on the topics consen with the notification_topics config option. Alternatively, a Notifier object can be instantiated with a specific driver or topic:: notifier = notifier.Notifier(RPC_TRANSPORT, 'compute.host', driver='messaging', topic='notifications') Notifier objects are relatively expensive to instantiate (mostly the cost of loading notification drivers), so it is possible to specialize a given Notifier object with a different publisher id using the prepare() method:: notifier = notifier.prepare(publisher_id='compute') notifier.info(ctxt, event_type, payload) """ def __init__(self, transport, publisher_id=None, driver=None, topic=None, serializer=None): """Construct a Notifier object. :param transport: the transport to use for sending messages :type transport: oslo.messaging.Transport :param publisher_id: field in notifications sent, e.g. 'compute.host1' :type publisher_id: str :param driver: a driver to lookup from oslo.messaging.notify.drivers :type driver: str :param topic: the topic which to send messages on :type topic: str :param serializer: an optional entity serializer :type serializer: Serializer """ self.conf = transport.conf self.conf.register_opts(_notifier_opts) self.transport = transport self.publisher_id = publisher_id self._driver_names = ([driver] if driver is not None else self.conf.notification_driver) self._topics = ([topic] if topic is not None else self.conf.notification_topics) self._serializer = serializer or msg_serializer.NoOpSerializer() self._driver_mgr = named.NamedExtensionManager( 'oslo.messaging.notify.drivers', names=self._driver_names, invoke_on_load=True, invoke_args=[self.conf], invoke_kwds={ 'topics': self._topics, 'transport': self.transport, }, ) _marker = object() def prepare(self, publisher_id=_marker): """Return a specialized Notifier instance. Returns a new Notifier instance with the supplied publisher_id. Allows sending notifications from multiple publisher_ids without the overhead of notification driver loading. :param publisher_id: field in notifications sent, e.g. 'compute.host1' :type publisher_id: str """ return _SubNotifier._prepare(self, publisher_id) def _notify(self, ctxt, event_type, payload, priority, publisher_id=None): payload = self._serializer.serialize_entity(ctxt, payload) ctxt = self._serializer.serialize_context(ctxt) msg = dict(message_id=uuidutils.generate_uuid(), publisher_id=publisher_id or self.publisher_id, event_type=event_type, priority=priority, payload=payload, timestamp=str(timeutils.utcnow())) def do_notify(ext): try: ext.obj.notify(ctxt, msg, priority) except Exception as e: _LOG.exception("Problem '%(e)s' attempting to send to " "notification system. Payload=%(payload)s", dict(e=e, payload=payload)) if self._driver_mgr.extensions: self._driver_mgr.map(do_notify) def debug(self, ctxt, event_type, payload): """Send a notification at debug level. :param ctxt: a request context dict :type ctxt: dict :param event_type: describes the event, e.g. 'compute.create_instance' :type event_type: str :param payload: the notification payload :type payload: dict """ self._notify(ctxt, event_type, payload, 'DEBUG') def info(self, ctxt, event_type, payload): """Send a notification at info level. :param ctxt: a request context dict :type ctxt: dict :param event_type: describes the event, e.g. 'compute.create_instance' :type event_type: str :param payload: the notification payload :type payload: dict """ self._notify(ctxt, event_type, payload, 'INFO') def warn(self, ctxt, event_type, payload): """Send a notification at warning level. :param ctxt: a request context dict :type ctxt: dict :param event_type: describes the event, e.g. 'compute.create_instance' :type event_type: str :param payload: the notification payload :type payload: dict """ self._notify(ctxt, event_type, payload, 'WARN') def error(self, ctxt, event_type, payload): """Send a notification at error level. :param ctxt: a request context dict :type ctxt: dict :param event_type: describes the event, e.g. 'compute.create_instance' :type event_type: str :param payload: the notification payload :type payload: dict """ self._notify(ctxt, event_type, payload, 'ERROR') def critical(self, ctxt, event_type, payload): """Send a notification at critical level. :param ctxt: a request context dict :type ctxt: dict :param event_type: describes the event, e.g. 'compute.create_instance' :type event_type: str :param payload: the notification payload :type payload: dict """ self._notify(ctxt, event_type, payload, 'CRITICAL') class _SubNotifier(Notifier): _marker = Notifier._marker def __init__(self, base, publisher_id): self._base = base self.conf = base.conf self.transport = base.transport self.publisher_id = publisher_id self._serializer = self._base._serializer self._driver_mgr = self._base._driver_mgr def _notify(self, ctxt, event_type, payload, priority): super(_SubNotifier, self)._notify(ctxt, event_type, payload, priority) @classmethod def _prepare(cls, base, publisher_id=_marker): if publisher_id is cls._marker: publisher_id = base.publisher_id return cls(base, publisher_id)