Files
oslo.messaging/oslo_messaging/_drivers/matchmaker_ring.py
Davanum Srinivas 588d795b3c Use proper translating helper for logging
Add hacking rule borrowed from keystone to make sure
we don't regress and fix all the issues found by the
hacking check.

Change-Id: I41635fdd83c3e04d04f9849a72c49ccb5ac42875
2015-08-20 21:01:59 -04:00

106 lines
3.4 KiB
Python

# Copyright 2011-2013 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 itertools
import json
import logging
from oslo_config import cfg
from oslo_messaging._drivers import matchmaker as mm
from oslo_messaging._i18n import _LW
matchmaker_opts = [
# Matchmaker ring file
cfg.StrOpt('ringfile',
deprecated_name='matchmaker_ringfile',
deprecated_group='DEFAULT',
default='/etc/oslo/matchmaker_ring.json',
help='Matchmaker ring file (JSON).'),
]
CONF = cfg.CONF
CONF.register_opts(matchmaker_opts, 'matchmaker_ring')
LOG = logging.getLogger(__name__)
class RingExchange(mm.Exchange):
"""Match Maker where hosts are loaded from a static JSON formatted file.
__init__ takes optional ring dictionary argument, otherwise
loads the ringfile from CONF.mathcmaker_ringfile.
"""
def __init__(self, ring=None):
super(RingExchange, self).__init__()
if ring:
self.ring = ring
else:
fh = open(CONF.matchmaker_ring.ringfile, 'r')
self.ring = json.load(fh)
fh.close()
self.ring0 = {}
for k in self.ring.keys():
self.ring0[k] = itertools.cycle(self.ring[k])
def _ring_has(self, key):
return key in self.ring0
class RoundRobinRingExchange(RingExchange):
"""A Topic Exchange based on a hashmap."""
def __init__(self, ring=None):
super(RoundRobinRingExchange, self).__init__(ring)
def run(self, key):
if not self._ring_has(key):
LOG.warn(
_LW("No key defining hosts for topic '%s', "
"see ringfile"), key
)
return []
host = next(self.ring0[key])
return [(key + '.' + host, host)]
class FanoutRingExchange(RingExchange):
"""Fanout Exchange based on a hashmap."""
def __init__(self, ring=None):
super(FanoutRingExchange, self).__init__(ring)
def run(self, key):
# Assume starts with "fanout~", strip it for lookup.
nkey = key.split('fanout~')[1:][0]
if not self._ring_has(nkey):
LOG.warn(
_LW("No key defining hosts for topic '%s', "
"see ringfile"), nkey
)
return []
return map(lambda x: (key + '.' + x, x), self.ring[nkey])
class MatchMakerRing(mm.MatchMakerBase):
"""Match Maker where hosts are loaded from a static hashmap."""
def __init__(self, ring=None):
super(MatchMakerRing, self).__init__()
self.add_binding(mm.FanoutBinding(), FanoutRingExchange(ring))
self.add_binding(mm.DirectBinding(), mm.DirectExchange())
self.add_binding(mm.TopicBinding(), RoundRobinRingExchange(ring))