vmware-nsx/quantum/openstack/common/rpc/matchmaker.py
Clark Boylan b5bf227db4 Perform a sync with oslo-incubator.
This oslo-incubator sync pulls in a new log.py which will make quantum's
default log output format the same as nova, glance and cinder (once
cinder's corresponding oslo sync merges). This common log format
simplifies log indexing as part of CI and makes lives easier for
deployers.

This sync does add a requirement on six as jsonutils depends on it. It
updates install_venv_common.py to be python26 compatible. It also brings
in a bunch of recent python3 compatibility that was added to oslo.

Fixes bug 1183144

Change-Id: Id0f196d7b5680e5950e4a27d66042bf00ccd49e6
2013-05-23 15:58:33 -07:00

349 lines
9.6 KiB
Python

# vim: tabstop=4 shiftwidth=4 softtabstop=4
# 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 eventlet
from oslo.config import cfg
from quantum.openstack.common.gettextutils import _
from quantum.openstack.common import log as logging
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 publically 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 publically 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):
if '.' in key:
return True
return False
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):
if '.' not in key:
return True
return False
class FanoutBinding(Binding):
"""Match on fanout keys, where key starts with 'fanout.' string."""
def test(self, key):
if key.startswith('fanout~'):
return True
return False
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(MatchMakerLocalhost, self).__init__()
self.add_binding(FanoutBinding(), StubExchange())
self.add_binding(DirectBinding(), StubExchange())
self.add_binding(TopicBinding(), StubExchange())