322 lines
9.2 KiB
Python
322 lines
9.2 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.
|
|
"""
|
|
The MatchMaker classes should except a Topic or Fanout exchange key and
|
|
return keys for direct exchanges, per (approximate) AMQP parlance.
|
|
"""
|
|
|
|
import contextlib
|
|
import logging
|
|
|
|
import eventlet
|
|
|
|
from oslo.config import cfg
|
|
from oslo.messaging.openstack.common.gettextutils import _
|
|
|
|
matchmaker_opts = [
|
|
cfg.IntOpt('matchmaker_heartbeat_freq',
|
|
default=300,
|
|
help='Heartbeat frequency.'),
|
|
cfg.IntOpt('matchmaker_heartbeat_ttl',
|
|
default=600,
|
|
help='Heartbeat time-to-live.'),
|
|
]
|
|
|
|
CONF = cfg.CONF
|
|
CONF.register_opts(matchmaker_opts)
|
|
LOG = logging.getLogger(__name__)
|
|
contextmanager = contextlib.contextmanager
|
|
|
|
|
|
class MatchMakerException(Exception):
|
|
"""Signified a match could not be found."""
|
|
message = _("Match not found by MatchMaker.")
|
|
|
|
|
|
class Exchange(object):
|
|
"""Implements lookups.
|
|
|
|
Subclass this to support hashtables, dns, etc.
|
|
"""
|
|
def __init__(self):
|
|
pass
|
|
|
|
def run(self, key):
|
|
raise NotImplementedError()
|
|
|
|
|
|
class Binding(object):
|
|
"""A binding on which to perform a lookup."""
|
|
def __init__(self):
|
|
pass
|
|
|
|
def test(self, key):
|
|
raise NotImplementedError()
|
|
|
|
|
|
class MatchMakerBase(object):
|
|
"""Match Maker Base Class.
|
|
|
|
Build off HeartbeatMatchMakerBase if building a heartbeat-capable
|
|
MatchMaker.
|
|
"""
|
|
def __init__(self):
|
|
# Array of tuples. Index [2] toggles negation, [3] is last-if-true
|
|
self.bindings = []
|
|
|
|
self.no_heartbeat_msg = _('Matchmaker does not implement '
|
|
'registration or heartbeat.')
|
|
|
|
def register(self, key, host):
|
|
"""Register a host on a backend.
|
|
|
|
Heartbeats, if applicable, may keepalive registration.
|
|
"""
|
|
pass
|
|
|
|
def ack_alive(self, key, host):
|
|
"""Acknowledge that a key.host is alive.
|
|
|
|
Used internally for updating heartbeats, but may also be used
|
|
publicly to acknowledge a system is alive (i.e. rpc message
|
|
successfully sent to host)
|
|
"""
|
|
pass
|
|
|
|
def is_alive(self, topic, host):
|
|
"""Checks if a host is alive."""
|
|
pass
|
|
|
|
def expire(self, topic, host):
|
|
"""Explicitly expire a host's registration."""
|
|
pass
|
|
|
|
def send_heartbeats(self):
|
|
"""Send all heartbeats.
|
|
|
|
Use start_heartbeat to spawn a heartbeat greenthread,
|
|
which loops this method.
|
|
"""
|
|
pass
|
|
|
|
def unregister(self, key, host):
|
|
"""Unregister a topic."""
|
|
pass
|
|
|
|
def start_heartbeat(self):
|
|
"""Spawn heartbeat greenthread."""
|
|
pass
|
|
|
|
def stop_heartbeat(self):
|
|
"""Destroys the heartbeat greenthread."""
|
|
pass
|
|
|
|
def add_binding(self, binding, rule, last=True):
|
|
self.bindings.append((binding, rule, False, last))
|
|
|
|
# NOTE(ewindisch): kept the following method in case we implement the
|
|
# underlying support.
|
|
# def add_negate_binding(self, binding, rule, last=True):
|
|
# self.bindings.append((binding, rule, True, last))
|
|
|
|
def queues(self, key):
|
|
workers = []
|
|
|
|
# bit is for negate bindings - if we choose to implement it.
|
|
# last stops processing rules if this matches.
|
|
for (binding, exchange, bit, last) in self.bindings:
|
|
if binding.test(key):
|
|
workers.extend(exchange.run(key))
|
|
|
|
# Support last.
|
|
if last:
|
|
return workers
|
|
return workers
|
|
|
|
|
|
class HeartbeatMatchMakerBase(MatchMakerBase):
|
|
"""Base for a heart-beat capable MatchMaker.
|
|
|
|
Provides common methods for registering, unregistering, and maintaining
|
|
heartbeats.
|
|
"""
|
|
def __init__(self):
|
|
self.hosts = set()
|
|
self._heart = None
|
|
self.host_topic = {}
|
|
|
|
super(HeartbeatMatchMakerBase, self).__init__()
|
|
|
|
def send_heartbeats(self):
|
|
"""Send all heartbeats.
|
|
|
|
Use start_heartbeat to spawn a heartbeat greenthread,
|
|
which loops this method.
|
|
"""
|
|
for key, host in self.host_topic:
|
|
self.ack_alive(key, host)
|
|
|
|
def ack_alive(self, key, host):
|
|
"""Acknowledge that a host.topic is alive.
|
|
|
|
Used internally for updating heartbeats, but may also be used
|
|
publicly to acknowledge a system is alive (i.e. rpc message
|
|
successfully sent to host)
|
|
"""
|
|
raise NotImplementedError("Must implement ack_alive")
|
|
|
|
def backend_register(self, key, host):
|
|
"""Implements registration logic.
|
|
|
|
Called by register(self,key,host)
|
|
"""
|
|
raise NotImplementedError("Must implement backend_register")
|
|
|
|
def backend_unregister(self, key, key_host):
|
|
"""Implements de-registration logic.
|
|
|
|
Called by unregister(self,key,host)
|
|
"""
|
|
raise NotImplementedError("Must implement backend_unregister")
|
|
|
|
def register(self, key, host):
|
|
"""Register a host on a backend.
|
|
|
|
Heartbeats, if applicable, may keepalive registration.
|
|
"""
|
|
self.hosts.add(host)
|
|
self.host_topic[(key, host)] = host
|
|
key_host = '.'.join((key, host))
|
|
|
|
self.backend_register(key, key_host)
|
|
|
|
self.ack_alive(key, host)
|
|
|
|
def unregister(self, key, host):
|
|
"""Unregister a topic."""
|
|
if (key, host) in self.host_topic:
|
|
del self.host_topic[(key, host)]
|
|
|
|
self.hosts.discard(host)
|
|
self.backend_unregister(key, '.'.join((key, host)))
|
|
|
|
LOG.info(_("Matchmaker unregistered: %(key)s, %(host)s"),
|
|
{'key': key, 'host': host})
|
|
|
|
def start_heartbeat(self):
|
|
"""Implementation of MatchMakerBase.start_heartbeat.
|
|
|
|
Launches greenthread looping send_heartbeats(),
|
|
yielding for CONF.matchmaker_heartbeat_freq seconds
|
|
between iterations.
|
|
"""
|
|
if not self.hosts:
|
|
raise MatchMakerException(
|
|
_("Register before starting heartbeat."))
|
|
|
|
def do_heartbeat():
|
|
while True:
|
|
self.send_heartbeats()
|
|
eventlet.sleep(CONF.matchmaker_heartbeat_freq)
|
|
|
|
self._heart = eventlet.spawn(do_heartbeat)
|
|
|
|
def stop_heartbeat(self):
|
|
"""Destroys the heartbeat greenthread."""
|
|
if self._heart:
|
|
self._heart.kill()
|
|
|
|
|
|
class DirectBinding(Binding):
|
|
"""Specifies a host in the key via a '.' character.
|
|
|
|
Although dots are used in the key, the behavior here is
|
|
that it maps directly to a host, thus direct.
|
|
"""
|
|
def test(self, key):
|
|
return '.' in key
|
|
|
|
|
|
class TopicBinding(Binding):
|
|
"""Where a 'bare' key without dots.
|
|
|
|
AMQP generally considers topic exchanges to be those *with* dots,
|
|
but we deviate here in terminology as the behavior here matches
|
|
that of a topic exchange (whereas where there are dots, behavior
|
|
matches that of a direct exchange.
|
|
"""
|
|
def test(self, key):
|
|
return '.' not in key
|
|
|
|
|
|
class FanoutBinding(Binding):
|
|
"""Match on fanout keys, where key starts with 'fanout.' string."""
|
|
def test(self, key):
|
|
return key.startswith('fanout~')
|
|
|
|
|
|
class StubExchange(Exchange):
|
|
"""Exchange that does nothing."""
|
|
def run(self, key):
|
|
return [(key, None)]
|
|
|
|
|
|
class LocalhostExchange(Exchange):
|
|
"""Exchange where all direct topics are local."""
|
|
def __init__(self, host='localhost'):
|
|
self.host = host
|
|
super(Exchange, self).__init__()
|
|
|
|
def run(self, key):
|
|
return [('.'.join((key.split('.')[0], self.host)), self.host)]
|
|
|
|
|
|
class DirectExchange(Exchange):
|
|
"""Exchange where all topic keys are split, sending to second half.
|
|
|
|
i.e. "compute.host" sends a message to "compute.host" running on "host"
|
|
"""
|
|
def __init__(self):
|
|
super(Exchange, self).__init__()
|
|
|
|
def run(self, key):
|
|
e = key.split('.', 1)[1]
|
|
return [(key, e)]
|
|
|
|
|
|
class MatchMakerLocalhost(MatchMakerBase):
|
|
"""Match Maker where all bare topics resolve to localhost.
|
|
|
|
Useful for testing.
|
|
"""
|
|
def __init__(self, host='localhost'):
|
|
super(MatchMakerLocalhost, self).__init__()
|
|
self.add_binding(FanoutBinding(), LocalhostExchange(host))
|
|
self.add_binding(DirectBinding(), DirectExchange())
|
|
self.add_binding(TopicBinding(), LocalhostExchange(host))
|
|
|
|
|
|
class MatchMakerStub(MatchMakerBase):
|
|
"""Match Maker where topics are untouched.
|
|
|
|
Useful for testing, or for AMQP/brokered queues.
|
|
Will not work where knowledge of hosts is known (i.e. zeromq)
|
|
"""
|
|
def __init__(self):
|
|
super(MatchMakerStub, self).__init__()
|
|
|
|
self.add_binding(FanoutBinding(), StubExchange())
|
|
self.add_binding(DirectBinding(), StubExchange())
|
|
self.add_binding(TopicBinding(), StubExchange())
|