/usr/lib/python2.7/dist-packages/oslo_messaging/dispatcher.py is in python-oslo.messaging 4.6.1-2ubuntu1.
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1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60 61 62 63 64 65 66 67 68 69 70 71 72 73 74 75 76 77 78 79 80 81 82 83 84 85 86 87 88 89 90 91 92 93 94 95 96 97 98 99 100 101 102 103 104 105 106 107 108 109 110 | # 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, post=None):
self._result = None
self._incoming = incoming
self._dispatch = dispatch
self._post = post
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)
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
Usually 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):
"""Called by the executor to get the DispatcherExecutorContext
:param incoming: list of messages
:type incoming: oslo_messging._drivers.base.IncomingMessage
:returns: DispatcherExecutorContext
:rtype: DispatcherExecutorContext
"""
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