oslo.messaging/oslo_messaging/_drivers/impl_zmq.py

218 lines
7.9 KiB
Python

# Copyright 2011 Cloudscaling Group, 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 logging
import os
import threading
from stevedore import driver
from oslo_messaging._drivers import base
from oslo_messaging._drivers import common as rpc_common
from oslo_messaging._drivers.zmq_driver.client import zmq_client
from oslo_messaging._drivers.zmq_driver.server import zmq_server
from oslo_messaging._drivers.zmq_driver import zmq_async
from oslo_messaging._drivers.zmq_driver import zmq_options
from oslo_messaging._i18n import _LE
RPCException = rpc_common.RPCException
LOG = logging.getLogger(__name__)
class LazyDriverItem(object):
def __init__(self, item_cls, *args, **kwargs):
self._lock = threading.Lock()
self.item = None
self.item_class = item_cls
self.args = args
self.kwargs = kwargs
self.process_id = os.getpid()
def get(self):
# NOTE(ozamiatin): Lazy initialization.
# All init stuff moved closer to usage point - lazy init.
# Better design approach is to initialize in the driver's
# __init__, but 'fork' extensively used by services
# breaks all things.
if self.item is not None and os.getpid() == self.process_id:
return self.item
with self._lock:
if self.item is None or os.getpid() != self.process_id:
self.process_id = os.getpid()
self.item = self.item_class(*self.args, **self.kwargs)
return self.item
def cleanup(self):
if self.item:
self.item.cleanup()
class ZmqDriver(base.BaseDriver):
"""ZeroMQ Driver implementation.
Provides implementation of RPC and Notifier APIs by means
of ZeroMQ library.
See :doc:`zmq_driver` for details.
"""
def __init__(self, conf, url, default_exchange=None,
allowed_remote_exmods=None):
"""Construct ZeroMQ driver.
Initialize driver options.
Construct matchmaker - pluggable interface to targets management
Name Service
Construct client and server controllers
:param conf: oslo messaging configuration object
:type conf: oslo_config.CONF
:param url: transport URL
:type url: TransportUrl
:param default_exchange: Not used in zmq implementation
:type default_exchange: None
:param allowed_remote_exmods: remote exception passing options
:type allowed_remote_exmods: list
"""
zmq = zmq_async.import_zmq()
if zmq is None:
raise ImportError(_LE("ZeroMQ is not available!"))
zmq_options.register_opts(conf)
self.conf = conf
self.allowed_remote_exmods = allowed_remote_exmods
self.matchmaker = driver.DriverManager(
'oslo.messaging.zmq.matchmaker',
self.get_matchmaker_backend(url),
).driver(self.conf, url=url)
client_cls = zmq_client.ZmqClientProxy
if conf.oslo_messaging_zmq.use_pub_sub and not \
conf.oslo_messaging_zmq.use_router_proxy:
client_cls = zmq_client.ZmqClientMixDirectPubSub
elif not conf.oslo_messaging_zmq.use_pub_sub and not \
conf.oslo_messaging_zmq.use_router_proxy:
client_cls = zmq_client.ZmqClientDirect
self.client = LazyDriverItem(
client_cls, self.conf, self.matchmaker,
self.allowed_remote_exmods)
self.notifier = LazyDriverItem(
client_cls, self.conf, self.matchmaker,
self.allowed_remote_exmods)
super(ZmqDriver, self).__init__(conf, url, default_exchange,
allowed_remote_exmods)
def get_matchmaker_backend(self, url):
zmq_transport, p, matchmaker_backend = url.transport.partition('+')
assert zmq_transport == 'zmq', "Needs to be zmq for this transport!"
if not matchmaker_backend:
return self.conf.oslo_messaging_zmq.rpc_zmq_matchmaker
elif matchmaker_backend not in zmq_options.MATCHMAKER_BACKENDS:
raise rpc_common.RPCException(
_LE("Incorrect matchmaker backend name %(backend_name)s!"
"Available names are: %(available_names)s") %
{"backend_name": matchmaker_backend,
"available_names": zmq_options.MATCHMAKER_BACKENDS})
return matchmaker_backend
def send(self, target, ctxt, message, wait_for_reply=None, timeout=None,
retry=None):
"""Send RPC message to server
:param target: Message destination target
:type target: oslo_messaging.Target
:param ctxt: Message context
:type ctxt: dict
:param message: Message payload to pass
:type message: dict
:param wait_for_reply: Waiting for reply flag
:type wait_for_reply: bool
:param timeout: Reply waiting timeout in seconds
:type timeout: int
:param retry: an optional default connection retries configuration
None or -1 means to retry forever
0 means no retry
N means N retries
:type retry: int
"""
client = self.client.get()
if wait_for_reply:
return client.send_call(target, ctxt, message, timeout, retry)
elif target.fanout:
client.send_fanout(target, ctxt, message, retry)
else:
client.send_cast(target, ctxt, message, retry)
def send_notification(self, target, ctxt, message, version, retry=None):
"""Send notification to server
:param target: Message destination target
:type target: oslo_messaging.Target
:param ctxt: Message context
:type ctxt: dict
:param message: Message payload to pass
:type message: dict
:param version: Messaging API version
:type version: str
:param retry: an optional default connection retries configuration
None or -1 means to retry forever
0 means no retry
N means N retries
:type retry: int
"""
client = self.notifier.get()
client.send_notify(target, ctxt, message, version, retry)
def listen(self, target, batch_size, batch_timeout):
"""Listen to a specified target on a server side
:param target: Message destination target
:type target: oslo_messaging.Target
"""
listener = zmq_server.ZmqServer(self, self.conf, self.matchmaker,
target)
return base.PollStyleListenerAdapter(listener, batch_size,
batch_timeout)
def listen_for_notifications(self, targets_and_priorities, pool,
batch_size, batch_timeout):
"""Listen to a specified list of targets on a server side
:param targets_and_priorities: List of pairs (target, priority)
:type targets_and_priorities: list
:param pool: Not used for zmq implementation
:type pool: object
"""
listener = zmq_server.ZmqNotificationServer(
self, self.conf, self.matchmaker, targets_and_priorities)
return base.PollStyleListenerAdapter(listener, batch_size,
batch_timeout)
def cleanup(self):
"""Cleanup all driver's connections finally
"""
self.client.cleanup()
self.notifier.cleanup()