oslo.messaging/oslo_messaging/_drivers/amqpdriver.py
2016-04-22 14:01:08 +00:00

514 lines
19 KiB
Python

# 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.
__all__ = ['AMQPDriverBase']
import logging
import threading
import time
import uuid
import cachetools
from oslo_utils import timeutils
from six import moves
import oslo_messaging
from oslo_messaging._drivers import amqp as rpc_amqp
from oslo_messaging._drivers import base
from oslo_messaging._drivers import common as rpc_common
from oslo_messaging._i18n import _
from oslo_messaging._i18n import _LE
from oslo_messaging._i18n import _LI
from oslo_messaging._i18n import _LW
LOG = logging.getLogger(__name__)
class AMQPIncomingMessage(base.RpcIncomingMessage):
def __init__(self, listener, ctxt, message, unique_id, msg_id, reply_q,
obsolete_reply_queues):
super(AMQPIncomingMessage, self).__init__(ctxt, message)
self.listener = listener
self.unique_id = unique_id
self.msg_id = msg_id
self.reply_q = reply_q
self._obsolete_reply_queues = obsolete_reply_queues
self.stopwatch = timeutils.StopWatch()
self.stopwatch.start()
def _send_reply(self, conn, reply=None, failure=None, log_failure=True):
if not self._obsolete_reply_queues.reply_q_valid(self.reply_q,
self.msg_id):
return
if failure:
failure = rpc_common.serialize_remote_exception(failure,
log_failure)
# NOTE(sileht): ending can be removed in N*, see Listener.wait()
# for more detail.
msg = {'result': reply, 'failure': failure, 'ending': True,
'_msg_id': self.msg_id}
rpc_amqp._add_unique_id(msg)
unique_id = msg[rpc_amqp.UNIQUE_ID]
LOG.debug("sending reply msg_id: %(msg_id)s "
"reply queue: %(reply_q)s "
"time elapsed: %(elapsed)ss", {
'msg_id': self.msg_id,
'unique_id': unique_id,
'reply_q': self.reply_q,
'elapsed': self.stopwatch.elapsed()})
conn.direct_send(self.reply_q, rpc_common.serialize_msg(msg))
def reply(self, reply=None, failure=None, log_failure=True):
if not self.msg_id:
# NOTE(Alexei_987) not sending reply, if msg_id is empty
# because reply should not be expected by caller side
return
# NOTE(sileht): return without hold the a connection if possible
if not self._obsolete_reply_queues.reply_q_valid(self.reply_q,
self.msg_id):
return
# NOTE(sileht): we read the configuration value from the driver
# to be able to backport this change in previous version that
# still have the qpid driver
duration = self.listener.driver.missing_destination_retry_timeout
timer = rpc_common.DecayingTimer(duration=duration)
timer.start()
while True:
try:
with self.listener.driver._get_connection(
rpc_common.PURPOSE_SEND) as conn:
self._send_reply(conn, reply, failure,
log_failure=log_failure)
return
except rpc_amqp.AMQPDestinationNotFound:
if timer.check_return() > 0:
LOG.debug(("The reply %(msg_id)s cannot be sent "
"%(reply_q)s reply queue don't exist, "
"retrying..."), {
'msg_id': self.msg_id,
'reply_q': self.reply_q})
time.sleep(0.25)
else:
self._obsolete_reply_queues.add(self.reply_q, self.msg_id)
LOG.info(_LI("The reply %(msg_id)s cannot be sent "
"%(reply_q)s reply queue don't exist after "
"%(duration)s sec abandoning..."), {
'msg_id': self.msg_id,
'reply_q': self.reply_q,
'duration': duration})
return
def acknowledge(self):
self.message.acknowledge()
self.listener.msg_id_cache.add(self.unique_id)
def requeue(self):
# NOTE(sileht): In case of the connection is lost between receiving the
# message and requeing it, this requeue call fail
# but because the message is not acknowledged and not added to the
# msg_id_cache, the message will be reconsumed, the only difference is
# the message stay at the beginning of the queue instead of moving to
# the end.
self.message.requeue()
class ObsoleteReplyQueuesCache(object):
"""Cache of reply queue id that doesn't exists anymore.
NOTE(sileht): In case of a broker restart/failover
a reply queue can be unreachable for short period
the IncomingMessage.send_reply will block for 60 seconds
in this case or until rabbit recovers.
But in case of the reply queue is unreachable because the
rpc client is really gone, we can have a ton of reply to send
waiting 60 seconds.
This leads to a starvation of connection of the pool
The rpc server take to much time to send reply, other rpc client will
raise TimeoutError because their don't receive their replies in time.
This object cache stores already known gone client to not wait 60 seconds
and hold a connection of the pool.
Keeping 200 last gone rpc client for 1 minute is enough
and doesn't hold to much memory.
"""
SIZE = 200
TTL = 60
def __init__(self):
self._lock = threading.RLock()
self._cache = cachetools.TTLCache(self.SIZE, self.TTL)
def reply_q_valid(self, reply_q, msg_id):
if reply_q in self._cache:
self._no_reply_log(reply_q, msg_id)
return False
return True
def add(self, reply_q, msg_id):
with self._lock:
self._cache.update({reply_q: msg_id})
self._no_reply_log(reply_q, msg_id)
def _no_reply_log(self, reply_q, msg_id):
LOG.warning(_LW("%(reply_queue)s doesn't exists, drop reply to "
"%(msg_id)s"), {'reply_queue': reply_q,
'msg_id': msg_id})
class AMQPListener(base.PollStyleListener):
def __init__(self, driver, conn):
super(AMQPListener, self).__init__(driver.prefetch_size)
self.driver = driver
self.conn = conn
self.msg_id_cache = rpc_amqp._MsgIdCache()
self.incoming = []
self._stopped = threading.Event()
self._obsolete_reply_queues = ObsoleteReplyQueuesCache()
def __call__(self, message):
ctxt = rpc_amqp.unpack_context(message)
unique_id = self.msg_id_cache.check_duplicate_message(message)
if ctxt.msg_id:
LOG.debug("received message msg_id: %(msg_id)s reply to "
"%(queue)s", {'queue': ctxt.reply_q,
'msg_id': ctxt.msg_id})
else:
LOG.debug("received message with unique_id: %s", unique_id)
self.incoming.append(AMQPIncomingMessage(self,
ctxt.to_dict(),
message,
unique_id,
ctxt.msg_id,
ctxt.reply_q,
self._obsolete_reply_queues))
@base.batch_poll_helper
def poll(self, timeout=None):
while not self._stopped.is_set():
if self.incoming:
return self.incoming.pop(0)
try:
self.conn.consume(timeout=timeout)
except rpc_common.Timeout:
return None
def stop(self):
self._stopped.set()
self.conn.stop_consuming()
def cleanup(self):
# Closes listener connection
self.conn.close()
class ReplyWaiters(object):
WAKE_UP = object()
def __init__(self):
self._queues = {}
self._wrn_threshold = 10
def get(self, msg_id, timeout):
try:
return self._queues[msg_id].get(block=True, timeout=timeout)
except moves.queue.Empty:
raise oslo_messaging.MessagingTimeout(
'Timed out waiting for a reply '
'to message ID %s' % msg_id)
def put(self, msg_id, message_data):
queue = self._queues.get(msg_id)
if not queue:
LOG.info(_LI('No calling threads waiting for msg_id : %s'), msg_id)
LOG.debug(' queues: %(queues)s, message: %(message)s',
{'queues': len(self._queues), 'message': message_data})
else:
queue.put(message_data)
def add(self, msg_id):
self._queues[msg_id] = moves.queue.Queue()
if len(self._queues) > self._wrn_threshold:
LOG.warning(_LW('Number of call queues is greater than warning '
'threshold: %(old_threshold)s. There could be a '
'leak. Increasing threshold to: %(threshold)s'),
{'old_threshold': self._wrn_threshold,
'threshold': self._wrn_threshold * 2})
self._wrn_threshold *= 2
def remove(self, msg_id):
del self._queues[msg_id]
class ReplyWaiter(object):
def __init__(self, reply_q, conn, allowed_remote_exmods):
self.conn = conn
self.allowed_remote_exmods = allowed_remote_exmods
self.msg_id_cache = rpc_amqp._MsgIdCache()
self.waiters = ReplyWaiters()
self.conn.declare_direct_consumer(reply_q, self)
self._thread_exit_event = threading.Event()
self._thread = threading.Thread(target=self.poll)
self._thread.daemon = True
self._thread.start()
def stop(self):
if self._thread:
self._thread_exit_event.set()
self.conn.stop_consuming()
self._thread.join()
self._thread = None
def poll(self):
while not self._thread_exit_event.is_set():
try:
self.conn.consume()
except Exception:
LOG.exception(_LE("Failed to process incoming message, "
"retrying..."))
def __call__(self, message):
message.acknowledge()
incoming_msg_id = message.pop('_msg_id', None)
if message.get('ending'):
LOG.debug("received reply msg_id: %s", incoming_msg_id)
self.waiters.put(incoming_msg_id, message)
def listen(self, msg_id):
self.waiters.add(msg_id)
def unlisten(self, msg_id):
self.waiters.remove(msg_id)
@staticmethod
def _raise_timeout_exception(msg_id):
raise oslo_messaging.MessagingTimeout(
_('Timed out waiting for a reply to message ID %s.') % msg_id)
def _process_reply(self, data):
self.msg_id_cache.check_duplicate_message(data)
if data['failure']:
failure = data['failure']
result = rpc_common.deserialize_remote_exception(
failure, self.allowed_remote_exmods)
else:
result = data.get('result', None)
ending = data.get('ending', False)
return result, ending
def wait(self, msg_id, timeout):
# NOTE(sileht): for each msg_id we receive two amqp message
# first one with the payload, a second one to ensure the other
# have finish to send the payload
# NOTE(viktors): We are going to remove this behavior in the N
# release, but we need to keep backward compatibility, so we should
# support both cases for now.
timer = rpc_common.DecayingTimer(duration=timeout)
timer.start()
final_reply = None
ending = False
while not ending:
timeout = timer.check_return(self._raise_timeout_exception, msg_id)
try:
message = self.waiters.get(msg_id, timeout=timeout)
except moves.queue.Empty:
self._raise_timeout_exception(msg_id)
reply, ending = self._process_reply(message)
if reply is not None:
# NOTE(viktors): This can be either first _send_reply() with an
# empty `result` field or a second _send_reply() with
# ending=True and no `result` field.
final_reply = reply
return final_reply
class AMQPDriverBase(base.BaseDriver):
missing_destination_retry_timeout = 0
def __init__(self, conf, url, connection_pool,
default_exchange=None, allowed_remote_exmods=None):
super(AMQPDriverBase, self).__init__(conf, url, default_exchange,
allowed_remote_exmods)
self._default_exchange = default_exchange
self._connection_pool = connection_pool
self._reply_q_lock = threading.Lock()
self._reply_q = None
self._reply_q_conn = None
self._waiter = None
def _get_exchange(self, target):
return target.exchange or self._default_exchange
def _get_connection(self, purpose=rpc_common.PURPOSE_SEND):
return rpc_common.ConnectionContext(self._connection_pool,
purpose=purpose)
def _get_reply_q(self):
with self._reply_q_lock:
if self._reply_q is not None:
return self._reply_q
reply_q = 'reply_' + uuid.uuid4().hex
conn = self._get_connection(rpc_common.PURPOSE_LISTEN)
self._waiter = ReplyWaiter(reply_q, conn,
self._allowed_remote_exmods)
self._reply_q = reply_q
self._reply_q_conn = conn
return self._reply_q
def _send(self, target, ctxt, message,
wait_for_reply=None, timeout=None,
envelope=True, notify=False, retry=None):
# FIXME(markmc): remove this temporary hack
class Context(object):
def __init__(self, d):
self.d = d
def to_dict(self):
return self.d
context = Context(ctxt)
msg = message
if wait_for_reply:
msg_id = uuid.uuid4().hex
msg.update({'_msg_id': msg_id})
msg.update({'_reply_q': self._get_reply_q()})
rpc_amqp._add_unique_id(msg)
unique_id = msg[rpc_amqp.UNIQUE_ID]
rpc_amqp.pack_context(msg, context)
if envelope:
msg = rpc_common.serialize_msg(msg)
if wait_for_reply:
self._waiter.listen(msg_id)
log_msg = "CALL msg_id: %s " % msg_id
else:
log_msg = "CAST unique_id: %s " % unique_id
try:
with self._get_connection(rpc_common.PURPOSE_SEND) as conn:
if notify:
exchange = self._get_exchange(target)
log_msg += "NOTIFY exchange '%(exchange)s'" \
" topic '%(topic)s'" % {
'exchange': exchange,
'topic': target.topic}
LOG.debug(log_msg)
conn.notify_send(exchange, target.topic, msg, retry=retry)
elif target.fanout:
log_msg += "FANOUT topic '%(topic)s'" % {
'topic': target.topic}
LOG.debug(log_msg)
conn.fanout_send(target.topic, msg, retry=retry)
else:
topic = target.topic
exchange = self._get_exchange(target)
if target.server:
topic = '%s.%s' % (target.topic, target.server)
log_msg += "exchange '%(exchange)s'" \
" topic '%(topic)s'" % {
'exchange': exchange,
'topic': target.topic}
LOG.debug(log_msg)
conn.topic_send(exchange_name=exchange, topic=topic,
msg=msg, timeout=timeout, retry=retry)
if wait_for_reply:
result = self._waiter.wait(msg_id, timeout)
if isinstance(result, Exception):
raise result
return result
finally:
if wait_for_reply:
self._waiter.unlisten(msg_id)
def send(self, target, ctxt, message, wait_for_reply=None, timeout=None,
retry=None):
return self._send(target, ctxt, message, wait_for_reply, timeout,
retry=retry)
def send_notification(self, target, ctxt, message, version, retry=None):
return self._send(target, ctxt, message,
envelope=(version == 2.0), notify=True, retry=retry)
def listen(self, target, batch_size, batch_timeout):
conn = self._get_connection(rpc_common.PURPOSE_LISTEN)
listener = AMQPListener(self, conn)
conn.declare_topic_consumer(exchange_name=self._get_exchange(target),
topic=target.topic,
callback=listener)
conn.declare_topic_consumer(exchange_name=self._get_exchange(target),
topic='%s.%s' % (target.topic,
target.server),
callback=listener)
conn.declare_fanout_consumer(target.topic, listener)
return base.PollStyleListenerAdapter(listener, batch_size,
batch_timeout)
def listen_for_notifications(self, targets_and_priorities, pool,
batch_size, batch_timeout):
conn = self._get_connection(rpc_common.PURPOSE_LISTEN)
listener = AMQPListener(self, conn)
for target, priority in targets_and_priorities:
conn.declare_topic_consumer(
exchange_name=self._get_exchange(target),
topic='%s.%s' % (target.topic, priority),
callback=listener, queue_name=pool)
return base.PollStyleListenerAdapter(listener, batch_size,
batch_timeout)
def cleanup(self):
if self._connection_pool:
self._connection_pool.empty()
self._connection_pool = None
with self._reply_q_lock:
if self._reply_q is not None:
self._waiter.stop()
self._reply_q_conn.close()
self._reply_q_conn = None
self._reply_q = None
self._waiter = None