oslo.messaging/oslo_messaging/dispatcher.py
ChangBo Guo(gcb) 6b20fa8597 Improvement of logging acorrding to oslo.i18n guideline
1. Use translation marker functions, their argument must just be a string
2. Any message with more than one variable should use named
   interpolation instead of positional to allow translators
   to move the variables around in the string to account for
   differences in grammar and writing direction.
3. String interpolation should be delayed to be handled by the logging
   code, rather than being done at the point of the logging call.
For more details, please refert to oslo.i18n guideline [1]

Note: this commit doesn't touch test code.

[1] http://docs.openstack.org/developer/oslo.i18n/guidelines.html

Change-Id: I5f013d65b20396bbe0e5a2cceaed2a33fad1af23
2016-01-07 13:26:55 +08:00

115 lines
3.5 KiB
Python

# 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 six
from oslo_messaging._i18n import _
__all__ = [
"DispatcherBase",
"DispatcherExecutorContext"
]
LOG = logging.getLogger(__name__)
class DispatcherExecutorContext(object):
"""Dispatcher executor context helper
A dispatcher can have work to do before and after the dispatch of the
request in the main server thread while the dispatcher itself can be
done in its own thread.
The executor can use the helper like this:
callback = dispatcher(incoming)
callback.prepare()
thread = MyWhateverThread()
thread.on_done(callback.done)
thread.run(callback.run)
"""
def __init__(self, incoming, dispatch, executor_callback=None,
post=None):
self._result = None
self._incoming = incoming
self._dispatch = dispatch
self._post = post
self._executor_callback = executor_callback
def run(self):
"""The incoming message dispath itself
Can be run in an other thread/greenlet/corotine if the executor is
able to do it.
"""
try:
self._result = self._dispatch(self._incoming,
self._executor_callback)
except Exception:
msg = _('The dispatcher method must catches all exceptions')
LOG.exception(msg)
raise RuntimeError(msg)
def done(self):
"""Callback after the incoming message have been dispathed
Should be ran in the main executor thread/greenlet/corotine
"""
# FIXME(sileht): this is not currently true, this works only because
# the driver connection used for polling write on the wire only to
# ack/requeue message, but what if one day, the driver do something
# else
if self._post is not None:
self._post(self._incoming, self._result)
@six.add_metaclass(abc.ABCMeta)
class DispatcherBase(object):
"Base class for dispatcher"
batch_size = 1
"Number of messages to wait before calling endpoints callacks"
batch_timeout = None
"Number of seconds to wait before calling endpoints callacks"
@abc.abstractmethod
def _listen(self, transport):
"""Initiate the driver Listener
Usualy the driver Listener is start with the transport helper methods:
* transport._listen()
* transport._listen_for_notifications()
:param transport: the transport object
:type transport: oslo_messaging.transport.Transport
:returns: a driver Listener object
:rtype: oslo_messaging._drivers.base.Listener
"""
@abc.abstractmethod
def __call__(self, incoming, executor_callback=None):
"""Called by the executor to get the DispatcherExecutorContext
:param incoming: list of messages
:type incoming: oslo_messging._drivers.base.IncomingMessage
:returns: DispatcherExecutorContext
:rtype: DispatcherExecutorContext
"""