305 lines
11 KiB
Python
305 lines
11 KiB
Python
# Copyright 2016, 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.
|
|
|
|
"""
|
|
Utilities that map from a Target address to a proper AMQP 1.0 address.
|
|
|
|
This module defines a utility class that translates a high level oslo.messaging
|
|
address (Target) into the message-level address used on the message bus. This
|
|
translation may be statically configured or determined when the connection to
|
|
the message bus is made.
|
|
|
|
The Target members that are used to generate the address are:
|
|
|
|
* exchange
|
|
* topic
|
|
* server flag
|
|
* fanout flag
|
|
|
|
In addition a 'service' tag is associated with the address. This tag determines
|
|
the service associated with an address (e.g. rpc or notification) so
|
|
that traffic can be partitioned based on its use.
|
|
"""
|
|
|
|
import abc
|
|
import logging
|
|
|
|
from oslo_messaging._i18n import _LW
|
|
from oslo_messaging.target import Target
|
|
|
|
__all__ = [
|
|
"keyify",
|
|
"AddresserFactory",
|
|
"SERVICE_RPC",
|
|
"SERVICE_NOTIFY"
|
|
]
|
|
|
|
SERVICE_RPC = 0
|
|
SERVICE_NOTIFY = 1
|
|
|
|
LOG = logging.getLogger(__name__)
|
|
|
|
|
|
def keyify(address, service=SERVICE_RPC):
|
|
"""Create a hashable key from a Target and service that will uniquely
|
|
identify the generated address. This key is used to map the abstract
|
|
oslo.messaging address to its corresponding AMQP link(s). This mapping may
|
|
be done before the connection is established.
|
|
"""
|
|
if isinstance(address, Target):
|
|
# service is important because the resolved address may be
|
|
# different based on whether or not this Target is used for
|
|
# notifications or RPC
|
|
return ("Target:{t={%s} e={%s} s={%s} f={%s} service={%s}}" %
|
|
(address.topic, address.exchange, address.server,
|
|
address.fanout, service))
|
|
else:
|
|
# absolute address can be used without modification
|
|
return "String:{%s}" % address
|
|
|
|
|
|
class Addresser(object):
|
|
"""Base class message bus address generator. Used to convert an
|
|
oslo.messaging address into an AMQP 1.0 address string used over the
|
|
connection to the message bus.
|
|
"""
|
|
def __init__(self, default_exchange):
|
|
self._default_exchange = default_exchange
|
|
|
|
def resolve(self, target, service):
|
|
if not isinstance(target, Target):
|
|
# an already resolved address
|
|
return target
|
|
# Return a link address for a given target
|
|
if target.fanout:
|
|
return self.multicast_address(target, service)
|
|
elif target.server:
|
|
return self.unicast_address(target, service)
|
|
else:
|
|
return self.anycast_address(target, service)
|
|
|
|
@abc.abstractmethod
|
|
def multicast_address(self, target, service):
|
|
"""Address used to broadcast to all subscribers
|
|
"""
|
|
|
|
@abc.abstractmethod
|
|
def unicast_address(self, target, service):
|
|
"""Address used to target a specific subscriber (direct)
|
|
"""
|
|
|
|
@abc.abstractmethod
|
|
def anycast_address(self, target, service):
|
|
"""Address used for shared subscribers (competing consumers)
|
|
"""
|
|
|
|
def _concat(self, sep, items):
|
|
return sep.join(filter(bool, items))
|
|
|
|
|
|
class LegacyAddresser(Addresser):
|
|
"""Legacy addresses are in the following format:
|
|
|
|
multicast: '$broadcast_prefix[.$vhost].$exchange.$topic.all'
|
|
unicast: '$server_prefix[.$vhost].$exchange.$topic.$server'
|
|
anycast: '$group_prefix[.$vhost].$exchange.$topic'
|
|
|
|
Legacy addresses do not distinguish RPC traffic from Notification traffic
|
|
"""
|
|
def __init__(self, default_exchange, server_prefix, broadcast_prefix,
|
|
group_prefix, vhost):
|
|
super(LegacyAddresser, self).__init__(default_exchange)
|
|
self._server_prefix = server_prefix
|
|
self._broadcast_prefix = broadcast_prefix
|
|
self._group_prefix = group_prefix
|
|
self._vhost = vhost
|
|
|
|
def multicast_address(self, target, service):
|
|
return self._concat(".",
|
|
[self._broadcast_prefix,
|
|
self._vhost,
|
|
target.exchange or self._default_exchange,
|
|
target.topic,
|
|
"all"])
|
|
|
|
def unicast_address(self, target, service=SERVICE_RPC):
|
|
return self._concat(".",
|
|
[self._server_prefix,
|
|
self._vhost,
|
|
target.exchange or self._default_exchange,
|
|
target.topic,
|
|
target.server])
|
|
|
|
def anycast_address(self, target, service=SERVICE_RPC):
|
|
return self._concat(".",
|
|
[self._group_prefix,
|
|
self._vhost,
|
|
target.exchange or self._default_exchange,
|
|
target.topic])
|
|
|
|
# for debug:
|
|
def _is_multicast(self, address):
|
|
return address.startswith(self._broadcast_prefix)
|
|
|
|
def _is_unicast(self, address):
|
|
return address.startswith(self._server_prefix)
|
|
|
|
def _is_anycast(self, address):
|
|
return address.startswith(self._group_prefix)
|
|
|
|
def _is_service(self, address, service):
|
|
# legacy addresses are the same for RPC or Notifications
|
|
return True
|
|
|
|
|
|
class RoutableAddresser(Addresser):
|
|
"""Routable addresses have different formats based their use. It starts
|
|
with a prefix that is determined by the type of traffic (RPC or
|
|
Notifications). The prefix is followed by a description of messaging
|
|
delivery semantics. The delivery may be one of: 'multicast', 'unicast', or
|
|
'anycast'. The delivery semantics are followed by information pulled from
|
|
the Target. The template is:
|
|
|
|
$prefix/$semantics[/$vhost]/$exchange/$topic[/$server]
|
|
|
|
Examples based on the default prefix and semantic values:
|
|
|
|
rpc-unicast: "openstack.org/om/rpc/unicast/my-exchange/my-topic/my-server"
|
|
notify-anycast: "openstack.org/om/notify/anycast/my-vhost/exchange/topic"
|
|
"""
|
|
|
|
def __init__(self, default_exchange, rpc_exchange, rpc_prefix,
|
|
notify_exchange, notify_prefix, unicast_tag, multicast_tag,
|
|
anycast_tag, vhost):
|
|
super(RoutableAddresser, self).__init__(default_exchange)
|
|
if not self._default_exchange:
|
|
self._default_exchange = "openstack"
|
|
|
|
# templates for address generation:
|
|
|
|
self._vhost = vhost
|
|
|
|
_rpc = rpc_prefix + "/"
|
|
self._rpc_prefix = _rpc
|
|
self._rpc_unicast = _rpc + unicast_tag
|
|
self._rpc_multicast = _rpc + multicast_tag
|
|
self._rpc_anycast = _rpc + anycast_tag
|
|
|
|
_notify = notify_prefix + "/"
|
|
self._notify_prefix = _notify
|
|
self._notify_unicast = _notify + unicast_tag
|
|
self._notify_multicast = _notify + multicast_tag
|
|
self._notify_anycast = _notify + anycast_tag
|
|
|
|
self._exchange = [
|
|
# SERVICE_RPC:
|
|
rpc_exchange or self._default_exchange or 'rpc',
|
|
# SERVICE_NOTIFY:
|
|
notify_exchange or self._default_exchange or 'notify'
|
|
]
|
|
|
|
def multicast_address(self, target, service=SERVICE_RPC):
|
|
if service == SERVICE_RPC:
|
|
prefix = self._rpc_multicast
|
|
else:
|
|
prefix = self._notify_multicast
|
|
return self._concat("/",
|
|
[prefix,
|
|
self._vhost,
|
|
target.exchange or self._exchange[service],
|
|
target.topic])
|
|
|
|
def unicast_address(self, target, service=SERVICE_RPC):
|
|
if service == SERVICE_RPC:
|
|
prefix = self._rpc_unicast
|
|
else:
|
|
prefix = self._notify_unicast
|
|
return self._concat("/",
|
|
[prefix,
|
|
self._vhost,
|
|
target.exchange or self._exchange[service],
|
|
target.topic,
|
|
target.server])
|
|
|
|
def anycast_address(self, target, service=SERVICE_RPC):
|
|
if service == SERVICE_RPC:
|
|
prefix = self._rpc_anycast
|
|
else:
|
|
prefix = self._notify_anycast
|
|
return self._concat("/",
|
|
[prefix,
|
|
self._vhost,
|
|
target.exchange or self._exchange[service],
|
|
target.topic])
|
|
|
|
# for debug:
|
|
def _is_multicast(self, address):
|
|
return (address.startswith(self._rpc_multicast) or
|
|
address.startswith(self._notify_multicast))
|
|
|
|
def _is_unicast(self, address):
|
|
return (address.startswith(self._rpc_unicast) or
|
|
address.startswith(self._notify_unicast))
|
|
|
|
def _is_anycast(self, address):
|
|
return (address.startswith(self._rpc_anycast) or
|
|
address.startswith(self._notify_anycast))
|
|
|
|
def _is_service(self, address, service):
|
|
return address.startswith(self._rpc_prefix if service == SERVICE_RPC
|
|
else self._notify_prefix)
|
|
|
|
|
|
class AddresserFactory(object):
|
|
"""Generates the proper Addresser based on configuration and the type of
|
|
message bus the driver is connected to.
|
|
"""
|
|
def __init__(self, default_exchange, mode, **kwargs):
|
|
self._default_exchange = default_exchange
|
|
self._mode = mode
|
|
self._kwargs = kwargs
|
|
|
|
def __call__(self, remote_properties, vhost=None):
|
|
# for backwards compatibility use legacy if dynamic and we're connected
|
|
# to qpidd or we cannot identify the message bus. This can be
|
|
# overridden via the configuration.
|
|
product = remote_properties.get('product', 'qpid-cpp')
|
|
|
|
# TODO(kgiusti): Router support was added in Newton. Remove this
|
|
# warning post Newton, once the driver has stabilized.
|
|
if product == "qpid-dispatch-router":
|
|
w = _LW("This is the initial release of support for message"
|
|
" routing technology. Be aware that messages are not"
|
|
" queued and may be discarded if there are no consumers"
|
|
" present.")
|
|
LOG.warning(w)
|
|
|
|
if self._mode == 'legacy' or (self._mode == 'dynamic' and
|
|
product == 'qpid-cpp'):
|
|
return LegacyAddresser(self._default_exchange,
|
|
self._kwargs['legacy_server_prefix'],
|
|
self._kwargs['legacy_broadcast_prefix'],
|
|
self._kwargs['legacy_group_prefix'],
|
|
vhost)
|
|
else:
|
|
return RoutableAddresser(self._default_exchange,
|
|
self._kwargs.get("rpc_exchange"),
|
|
self._kwargs["rpc_prefix"],
|
|
self._kwargs.get("notify_exchange"),
|
|
self._kwargs["notify_prefix"],
|
|
self._kwargs["unicast"],
|
|
self._kwargs["multicast"],
|
|
self._kwargs["anycast"],
|
|
vhost)
|