OpenStack library for messaging
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# Copyright 2011 OpenStack Foundation
#
# 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 functools
import itertools
import logging
import os
import socket
import ssl
import time
import uuid
import kombu
import kombu.connection
import kombu.entity
import kombu.exceptions
import kombu.messaging
import six
from six.moves.urllib import parse
from oslo.config import cfg
from oslo.messaging._drivers import amqp as rpc_amqp
from oslo.messaging._drivers import amqpdriver
from oslo.messaging._drivers import common as rpc_common
from oslo.messaging._i18n import _
from oslo.messaging import exceptions
from oslo.utils import netutils
rabbit_opts = [
cfg.StrOpt('kombu_ssl_version',
default='',
help='SSL version to use (valid only if SSL enabled). '
'valid values are TLSv1, SSLv23 and SSLv3. SSLv2 may '
'be available on some distributions.'
),
cfg.StrOpt('kombu_ssl_keyfile',
default='',
help='SSL key file (valid only if SSL enabled).'),
cfg.StrOpt('kombu_ssl_certfile',
default='',
help='SSL cert file (valid only if SSL enabled).'),
cfg.StrOpt('kombu_ssl_ca_certs',
default='',
help='SSL certification authority file '
'(valid only if SSL enabled).'),
cfg.FloatOpt('kombu_reconnect_delay',
default=1.0,
help='How long to wait before reconnecting in response to an '
'AMQP consumer cancel notification.'),
cfg.StrOpt('rabbit_host',
default='localhost',
help='The RabbitMQ broker address where a single node is '
'used.'),
cfg.IntOpt('rabbit_port',
default=5672,
help='The RabbitMQ broker port where a single node is used.'),
cfg.ListOpt('rabbit_hosts',
default=['$rabbit_host:$rabbit_port'],
help='RabbitMQ HA cluster host:port pairs.'),
cfg.BoolOpt('rabbit_use_ssl',
default=False,
help='Connect over SSL for RabbitMQ.'),
cfg.StrOpt('rabbit_userid',
default='guest',
help='The RabbitMQ userid.'),
cfg.StrOpt('rabbit_password',
default='guest',
help='The RabbitMQ password.',
secret=True),
cfg.StrOpt('rabbit_login_method',
default='AMQPLAIN',
help='The RabbitMQ login method.'),
cfg.StrOpt('rabbit_virtual_host',
default='/',
help='The RabbitMQ virtual host.'),
cfg.IntOpt('rabbit_retry_interval',
default=1,
help='How frequently to retry connecting with RabbitMQ.'),
cfg.IntOpt('rabbit_retry_backoff',
default=2,
help='How long to backoff for between retries when connecting '
'to RabbitMQ.'),
cfg.IntOpt('rabbit_max_retries',
default=0,
help='Maximum number of RabbitMQ connection retries. '
'Default is 0 (infinite retry count).'),
cfg.BoolOpt('rabbit_ha_queues',
default=False,
help='Use HA queues in RabbitMQ (x-ha-policy: all). '
'If you change this option, you must wipe the '
'RabbitMQ database.'),
# FIXME(markmc): this was toplevel in openstack.common.rpc
cfg.BoolOpt('fake_rabbit',
default=False,
help='If passed, use a fake RabbitMQ provider.'),
]
LOG = logging.getLogger(__name__)
def _get_queue_arguments(conf):
"""Construct the arguments for declaring a queue.
If the rabbit_ha_queues option is set, we declare a mirrored queue
as described here:
http://www.rabbitmq.com/ha.html
Setting x-ha-policy to all means that the queue will be mirrored
to all nodes in the cluster.
"""
return {'x-ha-policy': 'all'} if conf.rabbit_ha_queues else {}
class RabbitMessage(dict):
def __init__(self, raw_message):
super(RabbitMessage, self).__init__(
rpc_common.deserialize_msg(raw_message.payload))
self._raw_message = raw_message
def acknowledge(self):
self._raw_message.ack()
def requeue(self):
self._raw_message.requeue()
class ConsumerBase(object):
"""Consumer base class."""
def __init__(self, channel, callback, tag, **kwargs):
"""Declare a queue on an amqp channel.
'channel' is the amqp channel to use
'callback' is the callback to call when messages are received
'tag' is a unique ID for the consumer on the channel
queue name, exchange name, and other kombu options are
passed in here as a dictionary.
"""
self.callback = callback
self.tag = six.text_type(tag)
self.kwargs = kwargs
self.queue = None
self.reconnect(channel)
def reconnect(self, channel):
"""Re-declare the queue after a rabbit reconnect."""
self.channel = channel
self.kwargs['channel'] = channel
self.queue = kombu.entity.Queue(**self.kwargs)
self.queue.declare()
def _callback_handler(self, message, callback):
"""Call callback with deserialized message.
Messages that are processed and ack'ed.
"""
try:
callback(RabbitMessage(message))
except Exception:
LOG.exception(_("Failed to process message"
" ... skipping it."))
message.ack()
def consume(self, *args, **kwargs):
"""Actually declare the consumer on the amqp channel. This will
start the flow of messages from the queue. Using the
Connection.iterconsume() iterator will process the messages,
calling the appropriate callback.
If a callback is specified in kwargs, use that. Otherwise,
use the callback passed during __init__()
If kwargs['nowait'] is True, then this call will block until
a message is read.
"""
options = {'consumer_tag': self.tag}
options['nowait'] = kwargs.get('nowait', False)
callback = kwargs.get('callback', self.callback)
if not callback:
raise ValueError("No callback defined")
def _callback(raw_message):
message = self.channel.message_to_python(raw_message)
self._callback_handler(message, callback)
self.queue.consume(*args, callback=_callback, **options)
def cancel(self):
"""Cancel the consuming from the queue, if it has started."""
try:
self.queue.cancel(self.tag)
except KeyError as e:
# NOTE(comstud): Kludge to get around a amqplib bug
if six.text_type(e) != "u'%s'" % self.tag:
raise
self.queue = None
class DirectConsumer(ConsumerBase):
"""Queue/consumer class for 'direct'."""
def __init__(self, conf, channel, msg_id, callback, tag, **kwargs):
"""Init a 'direct' queue.
'channel' is the amqp channel to use
'msg_id' is the msg_id to listen on
'callback' is the callback to call when messages are received
'tag' is a unique ID for the consumer on the channel
Other kombu options may be passed
"""
# Default options
options = {'durable': False,
'queue_arguments': _get_queue_arguments(conf),
'auto_delete': True,
'exclusive': False}
options.update(kwargs)
exchange = kombu.entity.Exchange(name=msg_id,
type='direct',
durable=options['durable'],
auto_delete=options['auto_delete'])
super(DirectConsumer, self).__init__(channel,
callback,
tag,
name=msg_id,
exchange=exchange,
routing_key=msg_id,
**options)
class TopicConsumer(ConsumerBase):
"""Consumer class for 'topic'."""
def __init__(self, conf, channel, topic, callback, tag, exchange_name,
name=None, **kwargs):
"""Init a 'topic' queue.
:param channel: the amqp channel to use
:param topic: the topic to listen on
:paramtype topic: str
:param callback: the callback to call when messages are received
:param tag: a unique ID for the consumer on the channel
:param exchange_name: the exchange name to use
:param name: optional queue name, defaults to topic
:paramtype name: str
Other kombu options may be passed as keyword arguments
"""
# Default options
options = {'durable': conf.amqp_durable_queues,
'queue_arguments': _get_queue_arguments(conf),
'auto_delete': conf.amqp_auto_delete,
'exclusive': False}
options.update(kwargs)
exchange = kombu.entity.Exchange(name=exchange_name,
type='topic',
durable=options['durable'],
auto_delete=options['auto_delete'])
super(TopicConsumer, self).__init__(channel,
callback,
tag,
name=name or topic,
exchange=exchange,
routing_key=topic,
**options)
class FanoutConsumer(ConsumerBase):
"""Consumer class for 'fanout'."""
def __init__(self, conf, channel, topic, callback, tag, **kwargs):
"""Init a 'fanout' queue.
'channel' is the amqp channel to use
'topic' is the topic to listen on
'callback' is the callback to call when messages are received
'tag' is a unique ID for the consumer on the channel
Other kombu options may be passed
"""
unique = uuid.uuid4().hex
exchange_name = '%s_fanout' % topic
queue_name = '%s_fanout_%s' % (topic, unique)
# Default options
options = {'durable': False,
'queue_arguments': _get_queue_arguments(conf),
'auto_delete': True,
'exclusive': False}
options.update(kwargs)
exchange = kombu.entity.Exchange(name=exchange_name, type='fanout',
durable=options['durable'],
auto_delete=options['auto_delete'])
super(FanoutConsumer, self).__init__(channel, callback, tag,
name=queue_name,
exchange=exchange,
routing_key=topic,
**options)
class Publisher(object):
"""Base Publisher class."""
def __init__(self, channel, exchange_name, routing_key, **kwargs):
"""Init the Publisher class with the exchange_name, routing_key,
and other options
"""
self.exchange_name = exchange_name
self.routing_key = routing_key
self.kwargs = kwargs
self.reconnect(channel)
def reconnect(self, channel):
"""Re-establish the Producer after a rabbit reconnection."""
self.exchange = kombu.entity.Exchange(name=self.exchange_name,
**self.kwargs)
self.producer = kombu.messaging.Producer(exchange=self.exchange,
channel=channel,
routing_key=self.routing_key)
def send(self, msg, timeout=None):
"""Send a message."""
if timeout:
#
# AMQP TTL is in milliseconds when set in the header.
#
self.producer.publish(msg, headers={'ttl': (timeout * 1000)})
else:
self.producer.publish(msg)
class DirectPublisher(Publisher):
"""Publisher class for 'direct'."""
def __init__(self, conf, channel, topic, **kwargs):
"""Init a 'direct' publisher.
Kombu options may be passed as keyword args to override defaults
"""
options = {'durable': False,
'auto_delete': True,
'exclusive': False}
options.update(kwargs)
super(DirectPublisher, self).__init__(channel, topic, topic,
type='direct', **options)
class TopicPublisher(Publisher):
"""Publisher class for 'topic'."""
def __init__(self, conf, channel, exchange_name, topic, **kwargs):
"""Init a 'topic' publisher.
Kombu options may be passed as keyword args to override defaults
"""
options = {'durable': conf.amqp_durable_queues,
'auto_delete': conf.amqp_auto_delete,
'exclusive': False}
options.update(kwargs)
super(TopicPublisher, self).__init__(channel,
exchange_name,
topic,
type='topic',
**options)
class FanoutPublisher(Publisher):
"""Publisher class for 'fanout'."""
def __init__(self, conf, channel, topic, **kwargs):
"""Init a 'fanout' publisher.
Kombu options may be passed as keyword args to override defaults
"""
options = {'durable': False,
'auto_delete': True,
'exclusive': False}
options.update(kwargs)
super(FanoutPublisher, self).__init__(channel, '%s_fanout' % topic,
None, type='fanout', **options)
class NotifyPublisher(TopicPublisher):
"""Publisher class for 'notify'."""
def __init__(self, conf, channel, exchange_name, topic, **kwargs):
self.durable = kwargs.pop('durable', conf.amqp_durable_queues)
self.queue_arguments = _get_queue_arguments(conf)
super(NotifyPublisher, self).__init__(conf, channel, exchange_name,
topic, **kwargs)
def reconnect(self, channel):
super(NotifyPublisher, self).reconnect(channel)
# NOTE(jerdfelt): Normally the consumer would create the queue, but
# we do this to ensure that messages don't get dropped if the
# consumer is started after we do
queue = kombu.entity.Queue(channel=channel,
exchange=self.exchange,
durable=self.durable,
name=self.routing_key,
routing_key=self.routing_key,
queue_arguments=self.queue_arguments)
queue.declare()
class Connection(object):
"""Connection object."""
pools = {}
def __init__(self, conf, url):
self.consumers = []
self.consumer_num = itertools.count(1)
self.conf = conf
self.max_retries = self.conf.rabbit_max_retries
# Try forever?
if self.max_retries <= 0:
self.max_retries = None
self.interval_start = self.conf.rabbit_retry_interval
self.interval_stepping = self.conf.rabbit_retry_backoff
# max retry-interval = 30 seconds
self.interval_max = 30
self._ssl_params = self._fetch_ssl_params()
self._login_method = self.conf.rabbit_login_method
if url.virtual_host is not None:
virtual_host = url.virtual_host
else:
virtual_host = self.conf.rabbit_virtual_host
self._url = ''
if self.conf.fake_rabbit:
# TODO(sileht): use memory://virtual_host into
# unit tests to remove cfg.CONF.fake_rabbit
self._url = 'memory://%s/' % virtual_host
elif url.hosts:
for host in url.hosts:
transport = url.transport.replace('kombu+', '')
transport = url.transport.replace('rabbit', 'amqp')
self._url += '%s%s://%s:%s@%s:%s/%s' % (
";" if self._url else '',
transport,
parse.quote(host.username or ''),
parse.quote(host.password or ''),
host.hostname or '', str(host.port or 5672),
virtual_host)
else:
for adr in self.conf.rabbit_hosts:
hostname, port = netutils.parse_host_port(
adr, default_port=self.conf.rabbit_port)
self._url += '%samqp://%s:%s@%s:%s/%s' % (
";" if self._url else '',
parse.quote(self.conf.rabbit_userid),
parse.quote(self.conf.rabbit_password),
hostname, port,
virtual_host)
self._initial_pid = os.getpid()
self.do_consume = True
self.channel = None
self.connection = kombu.connection.Connection(
self._url, ssl=self._ssl_params, login_method=self._login_method,
failover_strategy="shuffle")
LOG.info(_('Connecting to AMQP server on %(hostname)s:%(port)d'),
{'hostname': self.connection.hostname,
'port': self.connection.port})
# NOTE(sileht): just ensure the connection is setuped at startup
self.ensure(error_callback=None,
method=lambda channel: True)
LOG.info(_('Connected to AMQP server on %(hostname)s:%(port)d'),
{'hostname': self.connection.hostname,
'port': self.connection.port})
if self.conf.fake_rabbit:
# Kludge to speed up tests.
self.connection.transport.polling_interval = 0.0
# FIXME(markmc): use oslo sslutils when it is available as a library
_SSL_PROTOCOLS = {
"tlsv1": ssl.PROTOCOL_TLSv1,
"sslv23": ssl.PROTOCOL_SSLv23,
"sslv3": ssl.PROTOCOL_SSLv3
}
try:
_SSL_PROTOCOLS["sslv2"] = ssl.PROTOCOL_SSLv2
except AttributeError:
pass
@classmethod
def validate_ssl_version(cls, version):
key = version.lower()
try:
return cls._SSL_PROTOCOLS[key]
except KeyError:
raise RuntimeError(_("Invalid SSL version : %s") % version)
def _fetch_ssl_params(self):
"""Handles fetching what ssl params should be used for the connection
(if any).
"""
ssl_params = dict()
# http://docs.python.org/library/ssl.html - ssl.wrap_socket
if self.conf.kombu_ssl_version:
ssl_params['ssl_version'] = self.validate_ssl_version(
self.conf.kombu_ssl_version)
if self.conf.kombu_ssl_keyfile:
ssl_params['keyfile'] = self.conf.kombu_ssl_keyfile
if self.conf.kombu_ssl_certfile:
ssl_params['certfile'] = self.conf.kombu_ssl_certfile
if self.conf.kombu_ssl_ca_certs:
ssl_params['ca_certs'] = self.conf.kombu_ssl_ca_certs
# We might want to allow variations in the
# future with this?
ssl_params['cert_reqs'] = ssl.CERT_REQUIRED
# Return the extended behavior or just have the default behavior
return ssl_params or None
def _setup_new_channel(self, new_channel):
"""Callback invoked when the kombu connection have created
a new channel, we use it the reconfigure our consumers.
"""
self.consumer_num = itertools.count(1)
for consumer in self.consumers:
consumer.reconnect(new_channel)
def ensure(self, error_callback, method, retry=None,
timeout_is_error=True):
"""Will retry up to retry number of times.
retry = None means use the value of rabbit_max_retries
retry = -1 means to retry forever
retry = 0 means no retry
retry = N means N retries
"""
current_pid = os.getpid()
if self._initial_pid != current_pid:
LOG.warn("Process forked after connection established! "
"This can results to unpredictable behavior. "
"See: http://docs.openstack.org/developer/"
"oslo.messaging/transport.html")
self._initial_pid = current_pid
if retry is None:
retry = self.max_retries
if retry is None or retry < 0:
retry = None
def on_error(exc, interval):
error_callback and error_callback(exc)
info = {'hostname': self.connection.hostname,
'port': self.connection.port,
'err_str': exc, 'sleep_time': interval}
if 'Socket closed' in six.text_type(exc):
LOG.error(_('AMQP server %(hostname)s:%(port)d closed'
' the connection. Check login credentials:'
' %(err_str)s'), info)
else:
LOG.error(_('AMQP server on %(hostname)s:%(port)d is '
'unreachable: %(err_str)s. Trying again in '
'%(sleep_time)d seconds.'), info)
# XXX(nic): when reconnecting to a RabbitMQ cluster
# with mirrored queues in use, the attempt to release the
# connection can hang "indefinitely" somewhere deep down
# in Kombu. Blocking the thread for a bit prior to
# release seems to kludge around the problem where it is
# otherwise reproduceable.
# TODO(sileht): Check if this is useful since we
# use kombu for HA connection, the interval_step
# should sufficient, because the underlying kombu transport
# connection object freed.
if self.conf.kombu_reconnect_delay > 0:
LOG.info(_("Delaying reconnect for %1.1f seconds...") %
self.conf.kombu_reconnect_delay)
time.sleep(self.conf.kombu_reconnect_delay)
recoverable_errors = (self.connection.recoverable_channel_errors +
self.connection.recoverable_connection_errors)
try:
autoretry_method = self.connection.autoretry(
method, channel=self.channel,
max_retries=retry,
errback=on_error,
interval_start=self.interval_start or 1,
interval_step=self.interval_stepping,
on_revive=self._setup_new_channel,
)
ret, channel = autoretry_method()
self.channel = channel
return ret
except recoverable_errors as exc:
# NOTE(sileht): number of retry exceeded and the connection
# is still broken
msg = _('Unable to connect to AMQP server on '
'%(hostname)s:%(port)d after %(retry)d '
'tries: %(err_str)s') % {
'hostname': self.connection.hostname,
'port': self.connection.port,
'err_str': exc,
'retry': retry}
LOG.error(msg)
raise exceptions.MessageDeliveryFailure(msg)
def close(self):
"""Close/release this connection."""
if self.connection:
self.connection.release()
self.connection = None
def reset(self):
"""Reset a connection so it can be used again."""
self.channel.close()
self.channel = self.connection.channel()
self.consumers = []
self._setup_new_channel(self.channel)
def declare_consumer(self, consumer_cls, topic, callback):
"""Create a Consumer using the class that was passed in and
add it to our list of consumers
"""
def _connect_error(exc):
log_info = {'topic': topic, 'err_str': exc}
LOG.error(_("Failed to declare consumer for topic '%(topic)s': "
"%(err_str)s"), log_info)
def _declare_consumer(channel):
consumer = consumer_cls(self.conf, channel, topic, callback,
six.next(self.consumer_num))
self.consumers.append(consumer)
return consumer
return self.ensure(_connect_error, _declare_consumer)
def iterconsume(self, limit=None, timeout=None):
"""Return an iterator that will consume from all queues/consumers."""
def _error_callback(exc):
LOG.exception(_('Failed to consume message from queue: %s'),
exc)
self.do_consume = True
def _consume(channel):
if self.do_consume:
queues_head = self.consumers[:-1] # not fanout.
queues_tail = self.consumers[-1] # fanout
for queue in queues_head:
queue.consume(nowait=True)
queues_tail.consume(nowait=False)
self.do_consume = False
try:
return self.connection.drain_events(timeout=timeout)
except socket.timeout as exc:
LOG.debug('Timed out waiting for RPC response: %s', exc)
raise rpc_common.Timeout()
for iteration in itertools.count(0):
if limit and iteration >= limit:
raise StopIteration
yield self.ensure(_error_callback, _consume)
def publisher_send(self, cls, topic, msg, timeout=None, retry=None,
**kwargs):
"""Send to a publisher based on the publisher class."""
def _error_callback(exc):
log_info = {'topic': topic, 'err_str': exc}
LOG.exception(_("Failed to publish message to topic "
"'%(topic)s': %(err_str)s"), log_info)
def _publish(channel):
publisher = cls(self.conf, channel, topic=topic, **kwargs)
publisher.send(msg, timeout)
self.ensure(_error_callback, _publish, retry=retry)
def declare_direct_consumer(self, topic, callback):
"""Create a 'direct' queue.
In nova's use, this is generally a msg_id queue used for
responses for call/multicall
"""
self.declare_consumer(DirectConsumer, topic, callback)
def declare_topic_consumer(self, exchange_name, topic, callback=None,
queue_name=None):
"""Create a 'topic' consumer."""
self.declare_consumer(functools.partial(TopicConsumer,
name=queue_name,
exchange_name=exchange_name,
),
topic, callback)
def declare_fanout_consumer(self, topic, callback):
"""Create a 'fanout' consumer."""
self.declare_consumer(FanoutConsumer, topic, callback)
def direct_send(self, msg_id, msg):
"""Send a 'direct' message."""
self.publisher_send(DirectPublisher, msg_id, msg)
def topic_send(self, exchange_name, topic, msg, timeout=None, retry=None):
"""Send a 'topic' message."""
self.publisher_send(TopicPublisher, topic, msg, timeout,
exchange_name=exchange_name, retry=retry)
def fanout_send(self, topic, msg, retry=None):
"""Send a 'fanout' message."""
self.publisher_send(FanoutPublisher, topic, msg, retry=retry)
def notify_send(self, exchange_name, topic, msg, retry=None, **kwargs):
"""Send a notify message on a topic."""
self.publisher_send(NotifyPublisher, topic, msg, timeout=None,
exchange_name=exchange_name, retry=retry, **kwargs)
def consume(self, limit=None, timeout=None):
"""Consume from all queues/consumers."""
it = self.iterconsume(limit=limit, timeout=timeout)
while True:
try:
six.next(it)
except StopIteration:
return
class RabbitDriver(amqpdriver.AMQPDriverBase):
def __init__(self, conf, url,
default_exchange=None,
allowed_remote_exmods=None):
conf.register_opts(rabbit_opts)
conf.register_opts(rpc_amqp.amqp_opts)
connection_pool = rpc_amqp.get_connection_pool(conf, url, Connection)
super(RabbitDriver, self).__init__(conf, url,
connection_pool,
default_exchange,
allowed_remote_exmods)
def require_features(self, requeue=True):
pass