# 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 import uuid from oslo_config import cfg from oslo_utils import timeutils import six from stevedore import named from oslo_messaging._i18n import _LE from oslo_messaging import serializer as msg_serializer from oslo_messaging import transport as msg_transport _notifier_opts = [ cfg.MultiStrOpt('driver', default=[], deprecated_name='notification_driver', deprecated_group='DEFAULT', help='The Drivers(s) to handle sending notifications. ' 'Possible values are messaging, messagingv2, ' 'routing, log, test, noop'), cfg.StrOpt('transport_url', deprecated_name='notification_transport_url', deprecated_group='DEFAULT', help='A URL representing the messaging driver to use for ' 'notifications. If not set, we fall back to the same ' 'configuration used for RPC.'), cfg.ListOpt('topics', default=['notifications', ], deprecated_opts=[ cfg.DeprecatedOpt('topics', group='rpc_notifier2'), cfg.DeprecatedOpt('notification_topics', group='DEFAULT') ], help='AMQP topic used for OpenStack notifications.'), ] _LOG = logging.getLogger(__name__) @six.add_metaclass(abc.ABCMeta) class Driver(object): """Base driver for Notifications""" def __init__(self, conf, topics, transport): """base driver initialization :param conf: configuration options :param topics: list of topics :param transport: transport driver to use """ self.conf = conf self.topics = topics self.transport = transport @abc.abstractmethod def notify(self, ctxt, msg, priority, retry): """send a single notification with a specific priority :param ctxt: current request context :param msg: message to be sent :type msg: str :param priority: priority of the message :type priority: str :param retry: an connection retries configuration None or -1 means to retry forever 0 means no retry N means N retries :type retry: int """ pass def get_notification_transport(conf, url=None, allowed_remote_exmods=None, aliases=None): conf.register_opts(_notifier_opts, group='oslo_messaging_notifications') if url is None: url = conf.oslo_messaging_notifications.transport_url return msg_transport.get_transport(conf, url, allowed_remote_exmods, aliases) 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': six.text_type(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 = messaging.Notifier(get_notification_transport(CONF), 'compute') and notifications are sent via drivers chosen with the driver config option and on the topics chosen with the topics config option in [oslo_messaging_notifications] section. Alternatively, a Notifier object can be instantiated with a specific driver or topic:: transport = notifier.get_notification_transport(CONF) notifier = notifier.Notifier(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, retry=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, for example '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 :param retry: an connection retries configuration None or -1 means to retry forever 0 means no retry N means N retries :type retry: int """ conf = transport.conf conf.register_opts(_notifier_opts, group='oslo_messaging_notifications') self.transport = transport self.publisher_id = publisher_id self.retry = retry self._driver_names = ([driver] if driver is not None else conf.oslo_messaging_notifications.driver) self._topics = ([topic] if topic is not None else conf.oslo_messaging_notifications.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=[conf], invoke_kwds={ 'topics': self._topics, 'transport': self.transport, } ) _marker = object() def prepare(self, publisher_id=_marker, retry=_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, for example 'compute.host1' :type publisher_id: str :param retry: an connection retries configuration None or -1 means to retry forever 0 means no retry N means N retries :type retry: int """ return _SubNotifier._prepare(self, publisher_id, retry=retry) def _notify(self, ctxt, event_type, payload, priority, publisher_id=None, retry=None): payload = self._serializer.serialize_entity(ctxt, payload) ctxt = self._serializer.serialize_context(ctxt) msg = dict(message_id=six.text_type(uuid.uuid4()), publisher_id=publisher_id or self.publisher_id, event_type=event_type, priority=priority, payload=payload, timestamp=six.text_type(timeutils.utcnow())) def do_notify(ext): try: ext.obj.notify(ctxt, msg, priority, retry or self.retry) except Exception as e: _LOG.exception(_LE("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 audit(self, ctxt, event_type, payload): """Send a notification at audit level. :param ctxt: a request context dict :type ctxt: dict :param event_type: describes the event, for example 'compute.create_instance' :type event_type: str :param payload: the notification payload :type payload: dict :raises: MessageDeliveryFailure """ self._notify(ctxt, event_type, payload, 'AUDIT') 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, for example 'compute.create_instance' :type event_type: str :param payload: the notification payload :type payload: dict :raises: MessageDeliveryFailure """ 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, for example 'compute.create_instance' :type event_type: str :param payload: the notification payload :type payload: dict :raises: MessageDeliveryFailure """ 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, for example 'compute.create_instance' :type event_type: str :param payload: the notification payload :type payload: dict :raises: MessageDeliveryFailure """ self._notify(ctxt, event_type, payload, 'WARN') warning = 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, for example 'compute.create_instance' :type event_type: str :param payload: the notification payload :type payload: dict :raises: MessageDeliveryFailure """ 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, for example 'compute.create_instance' :type event_type: str :param payload: the notification payload :type payload: dict :raises: MessageDeliveryFailure """ self._notify(ctxt, event_type, payload, 'CRITICAL') def sample(self, ctxt, event_type, payload): """Send a notification at sample level. Sample notifications are for high-frequency events that typically contain small payloads. eg: "CPU = 70%" Not all drivers support the sample level (log, for example) so these could be dropped. :param ctxt: a request context dict :type ctxt: dict :param event_type: describes the event, for example 'compute.create_instance' :type event_type: str :param payload: the notification payload :type payload: dict :raises: MessageDeliveryFailure """ self._notify(ctxt, event_type, payload, 'SAMPLE') class _SubNotifier(Notifier): _marker = Notifier._marker def __init__(self, base, publisher_id, retry): self._base = base self.transport = base.transport self.publisher_id = publisher_id self.retry = retry 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, retry=_marker): if publisher_id is cls._marker: publisher_id = base.publisher_id if retry is cls._marker: retry = base.retry return cls(base, publisher_id, retry=retry)