/usr/lib/python2.7/dist-packages/tooz/drivers/consul.py is in python-tooz 1.40.0-4.
This file is owned by root:root, with mode 0o644.
The actual contents of the file can be viewed below.
1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60 61 62 63 64 65 66 67 68 69 70 71 72 73 74 75 76 77 78 79 80 81 82 83 84 85 86 87 88 89 90 91 92 93 94 95 96 97 98 99 100 101 102 103 104 105 106 107 108 109 110 111 112 113 114 115 116 117 118 119 120 121 122 123 124 125 126 127 128 129 130 131 132 133 134 135 136 137 138 139 140 141 142 143 144 145 146 147 148 149 150 151 152 153 154 155 156 157 158 159 160 161 162 163 164 165 166 167 168 169 170 171 172 173 174 175 176 177 178 179 180 181 182 183 184 185 186 | # -*- coding: utf-8 -*-
#
# Copyright © 2015 Yahoo! 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.
from __future__ import absolute_import
import consul
from oslo_utils import encodeutils
import tooz
from tooz import coordination
from tooz.drivers import _retry
from tooz import locking
from tooz import utils
class ConsulLock(locking.Lock):
def __init__(self, name, node, address, session_id, client):
super(ConsulLock, self).__init__(name)
self._name = name
self._node = node
self._address = address
self._session_id = session_id
self._client = client
self.acquired = False
def acquire(self, blocking=True):
@_retry.retry(stop_max_delay=blocking)
def _acquire():
# Check if we are the owner and if we are simulate
# blocking (because consul will not block a second
# acquisition attempt by the same owner).
_index, value = self._client.kv.get(key=self._name)
if value and value.get('Session') == self._session_id:
if blocking is False:
return False
else:
raise _retry.Retry
else:
# The value can be anything.
gotten = self._client.kv.put(key=self._name,
value=u"I got it!",
acquire=self._session_id)
if gotten:
self.acquired = True
return True
if blocking is False:
return False
else:
raise _retry.Retry
return _acquire()
def release(self):
if not self.acquired:
return False
# Get the lock to verify the session ID's are same
_index, contents = self._client.kv.get(key=self._name)
if not contents:
return False
owner = contents.get('Session')
if owner == self._session_id:
removed = self._client.kv.put(key=self._name,
value=self._session_id,
release=self._session_id)
if removed:
self.acquired = False
return True
return False
class ConsulDriver(coordination.CoordinationDriver):
"""This driver uses `python-consul`_ client against `consul`_ servers.
The ConsulDriver implements a minimal set of coordination driver API(s)
needed to make Consul being used as an option for Distributed Locking. The
data is stored in Consul's key-value store.
To configure the client to your liking please refer
http://python-consul.readthedocs.org/en/latest/. Few options like 'ttl'
and 'namespace' will be passed as part of the options. 'ttl' governs the
duration till when the session holding the lock will be active.
.. _python-consul: http://python-consul.readthedocs.org/
.. _consul: https://consul.io/
"""
#: Default namespace when none is provided
TOOZ_NAMESPACE = u"tooz"
#: Default TTL
DEFAULT_TTL = 15
#: Default consul port if not provided.
DEFAULT_PORT = 8500
def __init__(self, member_id, parsed_url, options):
super(ConsulDriver, self).__init__()
options = utils.collapse(options)
self._executor = utils.ProxyExecutor.build("Consul", options)
self._host = parsed_url.hostname
self._port = parsed_url.port or self.DEFAULT_PORT
self._session_id = None
self._session_name = encodeutils.safe_decode(member_id)
self._ttl = int(options.get('ttl', self.DEFAULT_TTL))
namespace = options.get('namespace', self.TOOZ_NAMESPACE)
self._namespace = encodeutils.safe_decode(namespace)
self._client = None
def _start(self):
"""Create a client, register a node and create a session."""
self._executor.start()
# Create a consul client
if self._client is None:
self._client = consul.Consul(host=self._host, port=self._port)
local_agent = self._client.agent.self()
self._node = local_agent['Member']['Name']
self._address = local_agent['Member']['Addr']
# Register a Node
self._client.catalog.register(node=self._node,
address=self._address)
# Create a session
self._session_id = self._client.session.create(
name=self._session_name, node=self._node, ttl=self._ttl)
def _stop(self):
if self._client is not None:
if self._session_id is not None:
self._client.session.destroy(self._session_id)
self._session_id = None
self._client = None
self._executor.stop()
def get_lock(self, name):
real_name = self._paths_join(self._namespace, u"locks", name)
return ConsulLock(real_name, self._node, self._address,
session_id=self._session_id,
client=self._client)
@staticmethod
def _paths_join(*args):
pieces = []
for arg in args:
pieces.append(encodeutils.safe_decode(arg))
return u"/".join(pieces)
@staticmethod
def watch_join_group(group_id, callback):
raise tooz.NotImplemented
@staticmethod
def unwatch_join_group(group_id, callback):
raise tooz.NotImplemented
@staticmethod
def watch_leave_group(group_id, callback):
raise tooz.NotImplemented
@staticmethod
def unwatch_leave_group(group_id, callback):
raise tooz.NotImplemented
@staticmethod
def watch_elected_as_leader(group_id, callback):
raise tooz.NotImplemented
@staticmethod
def unwatch_elected_as_leader(group_id, callback):
raise tooz.NotImplemented
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