/usr/lib/python2.7/dist-packages/oslo_messaging/notify/dispatcher.py is in python-oslo.messaging 5.10.0-2.
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# All Rights Reserved.
# Copyright 2013 eNovance
#
# 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 itertools
import logging
import six
from oslo_messaging._i18n import _LW
from oslo_messaging import dispatcher
from oslo_messaging import serializer as msg_serializer
LOG = logging.getLogger(__name__)
PRIORITIES = ['audit', 'debug', 'info', 'warn', 'error', 'critical', 'sample']
class NotificationResult(object):
HANDLED = 'handled'
REQUEUE = 'requeue'
class NotificationDispatcher(dispatcher.DispatcherBase):
def __init__(self, endpoints, serializer):
self.endpoints = endpoints
self.serializer = serializer or msg_serializer.NoOpSerializer()
self._callbacks_by_priority = {}
for endpoint, prio in itertools.product(endpoints, PRIORITIES):
if hasattr(endpoint, prio):
method = getattr(endpoint, prio)
screen = getattr(endpoint, 'filter_rule', None)
self._callbacks_by_priority.setdefault(prio, []).append(
(screen, method))
@property
def supported_priorities(self):
return self._callbacks_by_priority.keys()
def dispatch(self, incoming):
"""Dispatch notification messages to the appropriate endpoint method.
"""
priority, raw_message, message = self._extract_user_message(incoming)
if priority not in PRIORITIES:
LOG.warning(_LW('Unknown priority "%s"'), priority)
return
for screen, callback in self._callbacks_by_priority.get(priority,
[]):
if screen and not screen.match(message["ctxt"],
message["publisher_id"],
message["event_type"],
message["metadata"],
message["payload"]):
continue
ret = self._exec_callback(callback, message)
if ret == NotificationResult.REQUEUE:
return ret
return NotificationResult.HANDLED
def _exec_callback(self, callback, message):
try:
return callback(message["ctxt"],
message["publisher_id"],
message["event_type"],
message["payload"],
message["metadata"])
except Exception:
LOG.exception("Callback raised an exception.")
return NotificationResult.REQUEUE
def _extract_user_message(self, incoming):
ctxt = self.serializer.deserialize_context(incoming.ctxt)
message = incoming.message
publisher_id = message.get('publisher_id')
event_type = message.get('event_type')
metadata = {
'message_id': message.get('message_id'),
'timestamp': message.get('timestamp')
}
priority = message.get('priority', '').lower()
payload = self.serializer.deserialize_entity(ctxt,
message.get('payload'))
return priority, incoming, dict(ctxt=ctxt,
publisher_id=publisher_id,
event_type=event_type,
payload=payload,
metadata=metadata)
class BatchNotificationDispatcher(NotificationDispatcher):
"""A message dispatcher which understands Notification messages.
A MessageHandlingServer is constructed by passing a callable dispatcher
which is invoked with a list of message dictionaries each time 'batch_size'
messages are received or 'batch_timeout' seconds is reached.
"""
def dispatch(self, incoming):
"""Dispatch notification messages to the appropriate endpoint method.
"""
messages_grouped = itertools.groupby((
self._extract_user_message(m)
for m in incoming), lambda x: x[0])
requeues = set()
for priority, messages in messages_grouped:
__, raw_messages, messages = six.moves.zip(*messages)
raw_messages = list(raw_messages)
messages = list(messages)
if priority not in PRIORITIES:
LOG.warning(_LW('Unknown priority "%s"'), priority)
continue
for screen, callback in self._callbacks_by_priority.get(priority,
[]):
if screen:
filtered_messages = [message for message in messages
if screen.match(
message["ctxt"],
message["publisher_id"],
message["event_type"],
message["metadata"],
message["payload"])]
else:
filtered_messages = messages
if not filtered_messages:
continue
ret = self._exec_callback(callback, filtered_messages)
if ret == NotificationResult.REQUEUE:
requeues.update(raw_messages)
break
return requeues
def _exec_callback(self, callback, messages):
try:
return callback(messages)
except Exception:
LOG.exception("Callback raised an exception.")
return NotificationResult.REQUEUE
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