OpenStack library for messaging
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# Copyright 2011 OpenStack Foundation
# 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 copy
import json
import threading
import time
from six import moves
import oslo_messaging
from oslo_messaging._drivers import base
class FakeIncomingMessage(base.IncomingMessage):
def __init__(self, listener, ctxt, message, reply_q, requeue):
super(FakeIncomingMessage, self).__init__(listener, ctxt, message)
self.requeue_callback = requeue
self._reply_q = reply_q
def reply(self, reply=None, failure=None, log_failure=True):
if self._reply_q:
failure = failure[1] if failure else None
self._reply_q.put((reply, failure))
def requeue(self):
self.requeue_callback()
class FakeListener(base.Listener):
def __init__(self, driver, exchange_manager, targets, pool=None):
super(FakeListener, self).__init__(driver)
self._exchange_manager = exchange_manager
self._targets = targets
self._pool = pool
self._stopped = threading.Event()
# NOTE(sileht): Ensure that all needed queues exists even the listener
# have not been polled yet
for target in self._targets:
exchange = self._exchange_manager.get_exchange(target.exchange)
exchange.ensure_queue(target, pool)
def poll(self, timeout=None):
if timeout is not None:
deadline = time.time() + timeout
else:
deadline = None
while not self._stopped.is_set():
for target in self._targets:
exchange = self._exchange_manager.get_exchange(target.exchange)
(ctxt, message, reply_q, requeue) = exchange.poll(target,
self._pool)
if message is not None:
message = FakeIncomingMessage(self, ctxt, message,
reply_q, requeue)
return message
if deadline is not None:
pause = deadline - time.time()
if pause < 0:
break
pause = min(pause, 0.050)
else:
pause = 0.050
time.sleep(pause)
return None
def stop(self):
self._stopped.set()
class FakeExchange(object):
def __init__(self, name):
self.name = name
self._queues_lock = threading.RLock()
self._topic_queues = {}
self._server_queues = {}
def ensure_queue(self, target, pool):
with self._queues_lock:
if target.server:
self._get_server_queue(target.topic, target.server)
else:
self._get_topic_queue(target.topic, pool)
def _get_topic_queue(self, topic, pool=None):
if pool and (topic, pool) not in self._topic_queues:
# NOTE(sileht): if the pool name is set, we need to
# copy all the already delivered messages from the
# default queue to this queue
self._topic_queues[(topic, pool)] = copy.deepcopy(
self._get_topic_queue(topic))
return self._topic_queues.setdefault((topic, pool), [])
def _get_server_queue(self, topic, server):
return self._server_queues.setdefault((topic, server), [])
def deliver_message(self, topic, ctxt, message,
server=None, fanout=False, reply_q=None):
with self._queues_lock:
if fanout:
queues = [q for t, q in self._server_queues.items()
if t[0] == topic]
elif server is not None:
queues = [self._get_server_queue(topic, server)]
else:
# NOTE(sileht): ensure at least the queue without
# pool name exists
self._get_topic_queue(topic)
queues = [q for t, q in self._topic_queues.items()
if t[0] == topic]
def requeue():
self.deliver_message(topic, ctxt, message, server=server,
fanout=fanout, reply_q=reply_q)
for queue in queues:
queue.append((ctxt, message, reply_q, requeue))
def poll(self, target, pool):
with self._queues_lock:
if target.server:
queue = self._get_server_queue(target.topic, target.server)
else:
queue = self._get_topic_queue(target.topic, pool)
return queue.pop(0) if queue else (None, None, None, None)
class FakeExchangeManager(object):
def __init__(self, default_exchange):
self._default_exchange = default_exchange
self._exchanges_lock = threading.Lock()
self._exchanges = {}
def get_exchange(self, name):
if name is None:
name = self._default_exchange
with self._exchanges_lock:
return self._exchanges.setdefault(name, FakeExchange(name))
class FakeDriver(base.BaseDriver):
def __init__(self, conf, url, default_exchange=None,
allowed_remote_exmods=None):
super(FakeDriver, self).__init__(conf, url, default_exchange,
allowed_remote_exmods)
self._exchange_manager = FakeExchangeManager(default_exchange)
def require_features(self, requeue=True):
pass
@staticmethod
def _check_serialize(message):
"""Make sure a message intended for rpc can be serialized.
We specifically want to use json, not our own jsonutils because
jsonutils has some extra logic to automatically convert objects to
primitive types so that they can be serialized. We want to catch all
cases where non-primitive types make it into this code and treat it as
an error.
"""
json.dumps(message)
def _send(self, target, ctxt, message, wait_for_reply=None, timeout=None):
self._check_serialize(message)
exchange = self._exchange_manager.get_exchange(target.exchange)
reply_q = None
if wait_for_reply:
reply_q = moves.queue.Queue()
exchange.deliver_message(target.topic, ctxt, message,
server=target.server,
fanout=target.fanout,
reply_q=reply_q)
if wait_for_reply:
try:
reply, failure = reply_q.get(timeout=timeout)
if failure:
raise failure
else:
return reply
except moves.queue.Empty:
raise oslo_messaging.MessagingTimeout(
'No reply on topic %s' % target.topic)
return None
def send(self, target, ctxt, message, wait_for_reply=None, timeout=None,
retry=None):
# NOTE(sileht): retry doesn't need to be implemented, the fake
# transport always works
return self._send(target, ctxt, message, wait_for_reply, timeout)
def send_notification(self, target, ctxt, message, version, retry=None):
# NOTE(sileht): retry doesn't need to be implemented, the fake
# transport always works
self._send(target, ctxt, message)
def listen(self, target):
exchange = target.exchange or self._default_exchange
listener = FakeListener(self, self._exchange_manager,
[oslo_messaging.Target(
topic=target.topic,
server=target.server,
exchange=exchange),
oslo_messaging.Target(
topic=target.topic,
exchange=exchange)])
return listener
def listen_for_notifications(self, targets_and_priorities, pool):
targets = [
oslo_messaging.Target(
topic='%s.%s' % (target.topic, priority),
exchange=target.exchange)
for target, priority in targets_and_priorities]
listener = FakeListener(self, self._exchange_manager, targets, pool)
return listener
def cleanup(self):
pass