/usr/lib/python2.7/dist-packages/tooz/drivers/mysql.py is in python-tooz 1.59.0-0ubuntu1.
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 99 100 101 102 103 104 105 106 107 108 109 110 111 112 113 114 115 116 117 118 119 120 121 122 123 124 125 126 127 128 129 130 131 132 133 134 135 136 137 138 139 140 141 142 143 144 145 146 147 148 149 150 151 152 153 154 155 156 157 158 159 160 161 162 163 164 165 166 167 168 169 170 171 172 173 174 175 176 177 178 179 180 181 182 183 184 185 186 187 188 189 190 191 192 193 194 195 196 197 198 | # -*- coding: utf-8 -*-
#
# Copyright © 2014 eNovance
#
# 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.
import logging
from oslo_utils import encodeutils
import pymysql
import tooz
from tooz import _retry
from tooz import coordination
from tooz import locking
from tooz import utils
LOG = logging.getLogger(__name__)
class MySQLLock(locking.Lock):
"""A MySQL based lock."""
MYSQL_DEFAULT_PORT = 3306
def __init__(self, name, parsed_url, options):
super(MySQLLock, self).__init__(name)
self.acquired = False
self._conn = MySQLDriver.get_connection(parsed_url, options, True)
def acquire(self, blocking=True, shared=False):
if shared:
raise tooz.NotImplemented
@_retry.retry(stop_max_delay=blocking)
def _lock():
# NOTE(sileht): mysql-server (<5.7.5) allows only one lock per
# connection at a time:
# select GET_LOCK("a", 0);
# select GET_LOCK("b", 0); <-- this release lock "a" ...
# Or
# select GET_LOCK("a", 0);
# select GET_LOCK("a", 0); release and lock again "a"
#
# So, we track locally the lock status with self.acquired
if self.acquired is True:
if blocking:
raise _retry.TryAgain
return False
try:
if not self._conn.open:
self._conn.connect()
with self._conn as cur:
cur.execute("SELECT GET_LOCK(%s, 0);", self.name)
# Can return NULL on error
if cur.fetchone()[0] is 1:
self.acquired = True
return True
except pymysql.MySQLError as e:
utils.raise_with_cause(
tooz.ToozError,
encodeutils.exception_to_unicode(e),
cause=e)
if blocking:
raise _retry.TryAgain
self._conn.close()
return False
try:
return _lock()
except Exception:
# Close the connection if we tried too much and finally failed, or
# anything else bad happened.
self._conn.close()
raise
def release(self):
if not self.acquired:
return False
try:
with self._conn as cur:
cur.execute("SELECT RELEASE_LOCK(%s);", self.name)
cur.fetchone()
self.acquired = False
self._conn.close()
return True
except pymysql.MySQLError as e:
utils.raise_with_cause(tooz.ToozError,
encodeutils.exception_to_unicode(e),
cause=e)
def __del__(self):
if self.acquired:
LOG.warning("unreleased lock %s garbage collected", self.name)
class MySQLDriver(coordination.CoordinationDriver):
"""A `MySQL`_ based driver.
This driver users `MySQL`_ database tables to
provide the coordination driver semantics and required API(s). It **is**
missing some functionality but in the future these not implemented API(s)
will be filled in.
.. _MySQL: http://dev.mysql.com/
"""
CHARACTERISTICS = (
coordination.Characteristics.NON_TIMEOUT_BASED,
coordination.Characteristics.DISTRIBUTED_ACROSS_THREADS,
coordination.Characteristics.DISTRIBUTED_ACROSS_PROCESSES,
coordination.Characteristics.DISTRIBUTED_ACROSS_HOSTS,
)
"""
Tuple of :py:class:`~tooz.coordination.Characteristics` introspectable
enum member(s) that can be used to interogate how this driver works.
"""
def __init__(self, member_id, parsed_url, options):
"""Initialize the MySQL driver."""
super(MySQLDriver, self).__init__(member_id, parsed_url, options)
self._parsed_url = parsed_url
self._options = utils.collapse(options)
def _start(self):
self._conn = MySQLDriver.get_connection(self._parsed_url,
self._options)
def _stop(self):
self._conn.close()
def get_lock(self, name):
return MySQLLock(name, self._parsed_url, self._options)
@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
@staticmethod
def get_connection(parsed_url, options, defer_connect=False):
host = parsed_url.hostname
port = parsed_url.port or MySQLLock.MYSQL_DEFAULT_PORT
dbname = parsed_url.path[1:]
username = parsed_url.username
password = parsed_url.password
unix_socket = options.get("unix_socket")
try:
if unix_socket:
return pymysql.Connect(unix_socket=unix_socket,
port=port,
user=username,
passwd=password,
database=dbname,
defer_connect=defer_connect)
else:
return pymysql.Connect(host=host,
port=port,
user=username,
passwd=password,
database=dbname,
defer_connect=defer_connect)
except (pymysql.err.OperationalError, pymysql.err.InternalError) as e:
utils.raise_with_cause(coordination.ToozConnectionError,
encodeutils.exception_to_unicode(e),
cause=e)
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