115 lines
3.4 KiB
Python
115 lines
3.4 KiB
Python
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# Copyright 2013 Red Hat, Inc.
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#
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# Licensed under the Apache License, Version 2.0 (the "License"); you may
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# not use this file except in compliance with the License. You may obtain
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# a copy of the License at
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#
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# http://www.apache.org/licenses/LICENSE-2.0
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#
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# Unless required by applicable law or agreed to in writing, software
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# distributed under the License is distributed on an "AS IS" BASIS, WITHOUT
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# WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. See the
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# License for the specific language governing permissions and limitations
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# under the License.
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import abc
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import six
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from oslo_messaging import exceptions
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class TransportDriverError(exceptions.MessagingException):
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"""Base class for transport driver specific exceptions."""
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@six.add_metaclass(abc.ABCMeta)
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class IncomingMessage(object):
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def __init__(self, listener, ctxt, message):
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self.conf = listener.conf
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self.listener = listener
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self.ctxt = ctxt
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self.message = message
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@abc.abstractmethod
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def reply(self, reply=None, failure=None, log_failure=True):
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"Send a reply or failure back to the client."
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def acknowledge(self):
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"Acknowledge the message."
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@abc.abstractmethod
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def requeue(self):
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"Requeue the message."
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@six.add_metaclass(abc.ABCMeta)
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class Listener(object):
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def __init__(self, driver):
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self.conf = driver.conf
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self.driver = driver
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@abc.abstractmethod
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def poll(self, timeout=None):
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"""Blocking until a message is pending and return IncomingMessage.
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Return None after timeout seconds if timeout is set and no message is
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ending or if the listener have been stopped.
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"""
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def stop(self):
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"""Stop listener.
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Stop the listener message polling
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"""
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pass
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def cleanup(self):
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"""Cleanup listener.
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Close connection used by listener if any. For some listeners like
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zmq there is no connection so no need to close connection.
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As this is listener specific method, overwrite it in to derived class
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if cleanup of listener required.
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"""
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pass
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@six.add_metaclass(abc.ABCMeta)
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class BaseDriver(object):
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def __init__(self, conf, url,
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default_exchange=None, allowed_remote_exmods=None):
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self.conf = conf
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self._url = url
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self._default_exchange = default_exchange
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self._allowed_remote_exmods = allowed_remote_exmods or []
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def require_features(self, requeue=False):
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if requeue:
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raise NotImplementedError('Message requeueing not supported by '
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'this transport driver')
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@abc.abstractmethod
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def send(self, target, ctxt, message,
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wait_for_reply=None, timeout=None, envelope=False):
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"""Send a message to the given target."""
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@abc.abstractmethod
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def send_notification(self, target, ctxt, message, version):
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"""Send a notification message to the given target."""
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@abc.abstractmethod
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def listen(self, target):
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"""Construct a Listener for the given target."""
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@abc.abstractmethod
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def listen_for_notifications(self, targets_and_priorities):
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"""Construct a notification Listener for the given list of
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tuple of (target, priority).
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"""
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@abc.abstractmethod
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def cleanup(self):
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"""Release all resources."""
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