OpenStack library for messaging
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# Copyright 2011 OpenStack Foundation
# Copyright 2011 - 2012, 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 functools
import itertools
import logging
import random
import time
import six
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 import exceptions
from oslo.messaging.openstack.common.gettextutils import _
from oslo.messaging.openstack.common import jsonutils
from oslo.utils import importutils
from oslo.utils import netutils
qpid_codec = importutils.try_import("qpid.codec010")
qpid_messaging = importutils.try_import("qpid.messaging")
qpid_exceptions = importutils.try_import("qpid.messaging.exceptions")
LOG = logging.getLogger(__name__)
qpid_opts = [
cfg.StrOpt('qpid_hostname',
default='localhost',
help='Qpid broker hostname.'),
cfg.IntOpt('qpid_port',
default=5672,
help='Qpid broker port.'),
cfg.ListOpt('qpid_hosts',
default=['$qpid_hostname:$qpid_port'],
help='Qpid HA cluster host:port pairs.'),
cfg.StrOpt('qpid_username',
default='',
help='Username for Qpid connection.'),
cfg.StrOpt('qpid_password',
default='',
help='Password for Qpid connection.',
secret=True),
cfg.StrOpt('qpid_sasl_mechanisms',
default='',
help='Space separated list of SASL mechanisms to use for '
'auth.'),
cfg.IntOpt('qpid_heartbeat',
default=60,
help='Seconds between connection keepalive heartbeats.'),
cfg.StrOpt('qpid_protocol',
default='tcp',
help="Transport to use, either 'tcp' or 'ssl'."),
cfg.BoolOpt('qpid_tcp_nodelay',
default=True,
help='Whether to disable the Nagle algorithm.'),
cfg.IntOpt('qpid_receiver_capacity',
default=1,
help='The number of prefetched messages held by receiver.'),
# NOTE(russellb) If any additional versions are added (beyond 1 and 2),
# this file could probably use some additional refactoring so that the
# differences between each version are split into different classes.
cfg.IntOpt('qpid_topology_version',
default=1,
help="The qpid topology version to use. Version 1 is what "
"was originally used by impl_qpid. Version 2 includes "
"some backwards-incompatible changes that allow broker "
"federation to work. Users should update to version 2 "
"when they are able to take everything down, as it "
"requires a clean break."),
]
JSON_CONTENT_TYPE = 'application/json; charset=utf8'
def raise_invalid_topology_version(conf):
msg = (_("Invalid value for qpid_topology_version: %d") %
conf.qpid_topology_version)
LOG.error(msg)
raise Exception(msg)
class QpidMessage(dict):
def __init__(self, session, raw_message):
super(QpidMessage, self).__init__(
rpc_common.deserialize_msg(raw_message.content))
self._raw_message = raw_message
self._session = session
def acknowledge(self):
self._session.acknowledge(self._raw_message)
def requeue(self):
pass
class ConsumerBase(object):
"""Consumer base class."""
def __init__(self, conf, session, callback, node_name, node_opts,
link_name, link_opts):
"""Declare a queue on an amqp session.
'session' is the amqp session to use
'callback' is the callback to call when messages are received
'node_name' is the first part of the Qpid address string, before ';'
'node_opts' will be applied to the "x-declare" section of "node"
in the address string.
'link_name' goes into the "name" field of the "link" in the address
string
'link_opts' will be applied to the "x-declare" section of "link"
in the address string.
"""
self.callback = callback
self.receiver = None
self.rcv_capacity = conf.qpid_receiver_capacity
self.session = None
if conf.qpid_topology_version == 1:
addr_opts = {
"create": "always",
"node": {
"type": "topic",
"x-declare": {
"durable": True,
"auto-delete": True,
},
},
"link": {
"durable": True,
"x-declare": {
"durable": False,
"auto-delete": True,
"exclusive": False,
},
},
}
addr_opts["node"]["x-declare"].update(node_opts)
elif conf.qpid_topology_version == 2:
addr_opts = {
"link": {
"x-declare": {
"auto-delete": True,
"exclusive": False,
},
},
}
else:
raise_invalid_topology_version(conf)
addr_opts["link"]["x-declare"].update(link_opts)
if link_name:
addr_opts["link"]["name"] = link_name
self.address = "%s ; %s" % (node_name, jsonutils.dumps(addr_opts))
self.connect(session)
def connect(self, session):
"""Declare the receiver on connect."""
self._declare_receiver(session)
def reconnect(self, session):
"""Re-declare the receiver after a Qpid reconnect."""
self._declare_receiver(session)
def _declare_receiver(self, session):
self.session = session
self.receiver = session.receiver(self.address)
self.receiver.capacity = self.rcv_capacity
def _unpack_json_msg(self, msg):
"""Load the JSON data in msg if msg.content_type indicates that it
is necessary. Put the loaded data back into msg.content and
update msg.content_type appropriately.
A Qpid Message containing a dict will have a content_type of
'amqp/map', whereas one containing a string that needs to be converted
back from JSON will have a content_type of JSON_CONTENT_TYPE.
:param msg: a Qpid Message object
:returns: None
"""
if msg.content_type == JSON_CONTENT_TYPE:
msg.content = jsonutils.loads(msg.content)
msg.content_type = 'amqp/map'
def consume(self):
"""Fetch the message and pass it to the callback object."""
message = self.receiver.fetch()
try:
self._unpack_json_msg(message)
self.callback(QpidMessage(self.session, message))
except Exception:
LOG.exception(_("Failed to process message... skipping it."))
self.session.acknowledge(message)
def get_receiver(self):
return self.receiver
def get_node_name(self):
return self.address.split(';')[0]
class DirectConsumer(ConsumerBase):
"""Queue/consumer class for 'direct'."""
def __init__(self, conf, session, msg_id, callback):
"""Init a 'direct' queue.
'session' is the amqp session to use
'msg_id' is the msg_id to listen on
'callback' is the callback to call when messages are received
"""
link_opts = {
"auto-delete": conf.amqp_auto_delete,
"exclusive": True,
"durable": conf.amqp_durable_queues,
}
if conf.qpid_topology_version == 1:
node_name = "%s/%s" % (msg_id, msg_id)
node_opts = {"type": "direct"}
link_name = msg_id
elif conf.qpid_topology_version == 2:
node_name = "amq.direct/%s" % msg_id
node_opts = {}
link_name = msg_id
else:
raise_invalid_topology_version(conf)
super(DirectConsumer, self).__init__(conf, session, callback,
node_name, node_opts, link_name,
link_opts)
class TopicConsumer(ConsumerBase):
"""Consumer class for 'topic'."""
def __init__(self, conf, session, topic, callback, exchange_name,
name=None):
"""Init a 'topic' queue.
:param session: the amqp session to use
:param topic: is the topic to listen on
:paramtype topic: str
:param callback: the callback to call when messages are received
:param name: optional queue name, defaults to topic
"""
link_opts = {
"auto-delete": conf.amqp_auto_delete,
"durable": conf.amqp_durable_queues,
}
if conf.qpid_topology_version == 1:
node_name = "%s/%s" % (exchange_name, topic)
elif conf.qpid_topology_version == 2:
node_name = "amq.topic/topic/%s/%s" % (exchange_name, topic)
else:
raise_invalid_topology_version(conf)
super(TopicConsumer, self).__init__(conf, session, callback, node_name,
{}, name or topic, link_opts)
class FanoutConsumer(ConsumerBase):
"""Consumer class for 'fanout'."""
def __init__(self, conf, session, topic, callback):
"""Init a 'fanout' queue.
'session' is the amqp session to use
'topic' is the topic to listen on
'callback' is the callback to call when messages are received
"""
self.conf = conf
link_opts = {"exclusive": True}
if conf.qpid_topology_version == 1:
node_name = "%s_fanout" % topic
node_opts = {"durable": False, "type": "fanout"}
elif conf.qpid_topology_version == 2:
node_name = "amq.topic/fanout/%s" % topic
node_opts = {}
else:
raise_invalid_topology_version(conf)
super(FanoutConsumer, self).__init__(conf, session, callback,
node_name, node_opts, None,
link_opts)
class Publisher(object):
"""Base Publisher class."""
def __init__(self, conf, session, node_name, node_opts=None):
"""Init the Publisher class with the exchange_name, routing_key,
and other options
"""
self.sender = None
self.session = session
if conf.qpid_topology_version == 1:
addr_opts = {
"create": "always",
"node": {
"type": "topic",
"x-declare": {
"durable": False,
# auto-delete isn't implemented for exchanges in qpid,
# but put in here anyway
"auto-delete": True,
},
},
}
if node_opts:
addr_opts["node"]["x-declare"].update(node_opts)
self.address = "%s ; %s" % (node_name, jsonutils.dumps(addr_opts))
elif conf.qpid_topology_version == 2:
self.address = node_name
else:
raise_invalid_topology_version(conf)
self.reconnect(session)
def reconnect(self, session):
"""Re-establish the Sender after a reconnection."""
self.sender = session.sender(self.address)
def _pack_json_msg(self, msg):
"""Qpid cannot serialize dicts containing strings longer than 65535
characters. This function dumps the message content to a JSON
string, which Qpid is able to handle.
:param msg: May be either a Qpid Message object or a bare dict.
:returns: A Qpid Message with its content field JSON encoded.
"""
try:
msg.content = jsonutils.dumps(msg.content)
except AttributeError:
# Need to have a Qpid message so we can set the content_type.
msg = qpid_messaging.Message(jsonutils.dumps(msg))
msg.content_type = JSON_CONTENT_TYPE
return msg
def send(self, msg):
"""Send a message."""
try:
# Check if Qpid can encode the message
check_msg = msg
if not hasattr(check_msg, 'content_type'):
check_msg = qpid_messaging.Message(msg)
content_type = check_msg.content_type
enc, dec = qpid_messaging.message.get_codec(content_type)
enc(check_msg.content)
except qpid_codec.CodecException:
# This means the message couldn't be serialized as a dict.
msg = self._pack_json_msg(msg)
self.sender.send(msg)
class DirectPublisher(Publisher):
"""Publisher class for 'direct'."""
def __init__(self, conf, session, topic):
"""Init a 'direct' publisher."""
if conf.qpid_topology_version == 1:
node_name = "%s/%s" % (topic, topic)
node_opts = {"type": "direct"}
elif conf.qpid_topology_version == 2:
node_name = "amq.direct/%s" % topic
node_opts = {}
else:
raise_invalid_topology_version(conf)
super(DirectPublisher, self).__init__(conf, session, node_name,
node_opts)
class TopicPublisher(Publisher):
"""Publisher class for 'topic'."""
def __init__(self, conf, session, exchange_name, topic):
"""Init a 'topic' publisher.
"""
if conf.qpid_topology_version == 1:
node_name = "%s/%s" % (exchange_name, topic)
elif conf.qpid_topology_version == 2:
node_name = "amq.topic/topic/%s/%s" % (exchange_name, topic)
else:
raise_invalid_topology_version(conf)
super(TopicPublisher, self).__init__(conf, session, node_name)
class FanoutPublisher(Publisher):
"""Publisher class for 'fanout'."""
def __init__(self, conf, session, topic):
"""Init a 'fanout' publisher.
"""
if conf.qpid_topology_version == 1:
node_name = "%s_fanout" % topic
node_opts = {"type": "fanout"}
elif conf.qpid_topology_version == 2:
node_name = "amq.topic/fanout/%s" % topic
node_opts = {}
else:
raise_invalid_topology_version(conf)
super(FanoutPublisher, self).__init__(conf, session, node_name,
node_opts)
class NotifyPublisher(Publisher):
"""Publisher class for notifications."""
def __init__(self, conf, session, exchange_name, topic):
"""Init a 'topic' publisher.
"""
node_opts = {"durable": True}
if conf.qpid_topology_version == 1:
node_name = "%s/%s" % (exchange_name, topic)
elif conf.qpid_topology_version == 2:
node_name = "amq.topic/topic/%s/%s" % (exchange_name, topic)
else:
raise_invalid_topology_version(conf)
super(NotifyPublisher, self).__init__(conf, session, node_name,
node_opts)
class Connection(object):
"""Connection object."""
pools = {}
def __init__(self, conf, url):
if not qpid_messaging:
raise ImportError("Failed to import qpid.messaging")
self.connection = None
self.session = None
self.consumers = {}
self.conf = conf
self.brokers_params = []
if url.hosts:
for host in url.hosts:
params = {
'username': host.username or '',
'password': host.password or '',
}
if host.port is not None:
params['host'] = '%s:%d' % (host.hostname, host.port)
else:
params['host'] = host.hostname
self.brokers_params.append(params)
else:
# Old configuration format
for adr in self.conf.qpid_hosts:
hostname, port = netutils.parse_host_port(
adr, default_port=5672)
params = {
'host': '%s:%d' % (hostname, port),
'username': self.conf.qpid_username,
'password': self.conf.qpid_password,
}
self.brokers_params.append(params)
random.shuffle(self.brokers_params)
self.brokers = itertools.cycle(self.brokers_params)
self.reconnect()
def _connect(self, broker):
# Create the connection - this does not open the connection
self.connection = qpid_messaging.Connection(broker['host'])
# Check if flags are set and if so set them for the connection
# before we call open
self.connection.username = broker['username']
self.connection.password = broker['password']
self.connection.sasl_mechanisms = self.conf.qpid_sasl_mechanisms
# Reconnection is done by self.reconnect()
self.connection.reconnect = False
self.connection.heartbeat = self.conf.qpid_heartbeat
self.connection.transport = self.conf.qpid_protocol
self.connection.tcp_nodelay = self.conf.qpid_tcp_nodelay
self.connection.open()
def _register_consumer(self, consumer):
self.consumers[six.text_type(consumer.get_receiver())] = consumer
def _lookup_consumer(self, receiver):
return self.consumers[six.text_type(receiver)]
def _disconnect(self):
# Close the session if necessary
if self.connection is not None and self.connection.opened():
try:
self.connection.close()
except qpid_exceptions.MessagingError:
pass
self.connection = None
def reconnect(self, retry=None):
"""Handles reconnecting and re-establishing sessions and queues.
Will retry up to retry number of times.
retry = None or -1 means to retry forever
retry = 0 means no retry
retry = N means N retries
"""
delay = 1
attempt = 0
loop_forever = False
if retry is None or retry < 0:
loop_forever = True
while True:
self._disconnect()
attempt += 1
broker = six.next(self.brokers)
try:
self._connect(broker)
except qpid_exceptions.MessagingError as e:
msg_dict = dict(e=e,
delay=delay,
retry=retry,
broker=broker)
if not loop_forever and attempt > retry:
msg = _('Unable to connect to AMQP server on '
'%(broker)s after %(retry)d '
'tries: %(e)s') % msg_dict
LOG.error(msg)
raise exceptions.MessageDeliveryFailure(msg)
else:
msg = _("Unable to connect to AMQP server on %(broker)s: "
"%(e)s. Sleeping %(delay)s seconds") % msg_dict
LOG.error(msg)
time.sleep(delay)
delay = min(delay + 1, 5)
else:
LOG.info(_('Connected to AMQP server on %s'), broker['host'])
break
self.session = self.connection.session()
if self.consumers:
consumers = self.consumers
self.consumers = {}
for consumer in six.itervalues(consumers):
consumer.reconnect(self.session)
self._register_consumer(consumer)
LOG.debug("Re-established AMQP queues")
def ensure(self, error_callback, method, retry=None):
while True:
try:
return method()
except (qpid_exceptions.Empty,
qpid_exceptions.MessagingError) as e:
if error_callback:
error_callback(e)
self.reconnect(retry=retry)
def close(self):
"""Close/release this connection."""
try:
self.connection.close()
except Exception:
# NOTE(dripton) Logging exceptions that happen during cleanup just
# causes confusion; there's really nothing useful we can do with
# them.
pass
self.connection = None
def reset(self):
"""Reset a connection so it can be used again."""
self.session.close()
self.session = self.connection.session()
self.consumers = {}
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():
consumer = consumer_cls(self.conf, self.session, topic, callback)
self._register_consumer(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):
if isinstance(exc, qpid_exceptions.Empty):
LOG.debug('Timed out waiting for RPC response: %s', exc)
raise rpc_common.Timeout()
else:
LOG.exception(_('Failed to consume message from queue: %s'),
exc)
def _consume():
nxt_receiver = self.session.next_receiver(timeout=timeout)
try:
self._lookup_consumer(nxt_receiver).consume()
except Exception:
LOG.exception(_("Error processing message. Skipping it."))
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, retry=None, **kwargs):
"""Send to a publisher based on the publisher class."""
def _connect_error(exc):
log_info = {'topic': topic, 'err_str': exc}
LOG.exception(_("Failed to publish message to topic "
"'%(topic)s': %(err_str)s"), log_info)
def _publisher_send():
publisher = cls(self.conf, self.session, topic=topic, **kwargs)
publisher.send(msg)
return self.ensure(_connect_error, _publisher_send, 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, topic=msg_id, msg=msg)
def topic_send(self, exchange_name, topic, msg, timeout=None, retry=None):
"""Send a 'topic' message."""
#
# We want to create a message with attributes, for example a TTL. We
# don't really need to keep 'msg' in its JSON format any longer
# so let's create an actual Qpid message here and get some
# value-add on the go.
#
# WARNING: Request timeout happens to be in the same units as
# Qpid's TTL (seconds). If this changes in the future, then this
# will need to be altered accordingly.
#
qpid_message = qpid_messaging.Message(content=msg, ttl=timeout)
self.publisher_send(TopicPublisher, topic=topic, msg=qpid_message,
exchange_name=exchange_name, retry=retry)
def fanout_send(self, topic, msg, retry=None):
"""Send a 'fanout' message."""
self.publisher_send(FanoutPublisher, topic=topic, msg=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=topic, msg=msg,
exchange_name=exchange_name, retry=retry)
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 QpidDriver(amqpdriver.AMQPDriverBase):
def __init__(self, conf, url,
default_exchange=None, allowed_remote_exmods=None):
conf.register_opts(qpid_opts)
conf.register_opts(rpc_amqp.amqp_opts)
connection_pool = rpc_amqp.get_connection_pool(conf, url, Connection)
super(QpidDriver, self).__init__(conf, url,
connection_pool,
default_exchange,
allowed_remote_exmods)