222 lines
7.4 KiB
Python
222 lines
7.4 KiB
Python
# vim: tabstop=4 shiftwidth=4 softtabstop=4
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# Copyright 2011 Nicira Networks, Inc.
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# All Rights Reserved.
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#
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# Licensed under the Apache License, Version 2.0 (the "License"); you may
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# not use this file except in compliance with the License. You may obtain
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# a copy of the License at
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#
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# http://www.apache.org/licenses/LICENSE-2.0
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#
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# Unless required by applicable law or agreed to in writing, software
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# distributed under the License is distributed on an "AS IS" BASIS, WITHOUT
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# WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. See the
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# License for the specific language governing permissions and limitations
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# under the License.
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# @author: Somik Behera, Nicira Networks, Inc.
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# @author: Brad Hall, Nicira Networks, Inc.
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# @author: Dan Wendlandt, Nicira Networks, Inc.
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import time
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from eventlet import db_pool
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from eventlet import greenthread
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try:
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import MySQLdb
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except ImportError:
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MySQLdb = None
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import sqlalchemy as sql
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from sqlalchemy import create_engine
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from sqlalchemy.exc import DisconnectionError
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from sqlalchemy.interfaces import PoolListener
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from sqlalchemy.orm import sessionmaker
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from quantum.db import model_base
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from quantum.openstack.common import cfg
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from quantum.openstack.common import log as logging
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LOG = logging.getLogger(__name__)
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database_opts = [
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cfg.StrOpt('sql_connection', default='sqlite://',
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help=_('The SQLAlchemy connection string used to connect to '
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'the database')),
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cfg.IntOpt('sql_max_retries', default=-1,
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help=_('Database reconnection retry times')),
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cfg.IntOpt('reconnect_interval', default=2,
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help=_('Database reconnection interval in seconds')),
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cfg.IntOpt('sql_min_pool_size',
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default=1,
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help=_("Minimum number of SQL connections to keep open in a "
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"pool")),
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cfg.IntOpt('sql_max_pool_size',
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default=5,
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help=_("Maximum number of SQL connections to keep open in a "
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"pool")),
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cfg.IntOpt('sql_idle_timeout',
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default=3600,
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help=_("Timeout in seconds before idle sql connections are "
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"reaped")),
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cfg.BoolOpt('sql_dbpool_enable',
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default=False,
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help=_("Enable the use of eventlet's db_pool for MySQL")),
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]
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cfg.CONF.register_opts(database_opts, "DATABASE")
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_ENGINE = None
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_MAKER = None
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BASE = model_base.BASEV2
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class MySQLPingListener(object):
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"""
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Ensures that MySQL connections checked out of the
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pool are alive.
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Borrowed from:
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http://groups.google.com/group/sqlalchemy/msg/a4ce563d802c929f
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"""
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def checkout(self, dbapi_con, con_record, con_proxy):
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try:
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dbapi_con.cursor().execute('select 1')
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except dbapi_con.OperationalError, ex:
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if ex.args[0] in (2006, 2013, 2014, 2045, 2055):
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LOG.warn(_('Got mysql server has gone away: %s'), ex)
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raise DisconnectionError(_("Database server went away"))
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else:
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raise
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class SqliteForeignKeysListener(PoolListener):
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"""
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Ensures that the foreign key constraints are enforced in SQLite.
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The foreign key constraints are disabled by default in SQLite,
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so the foreign key constraints will be enabled here for every
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database connection
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"""
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def connect(self, dbapi_con, con_record):
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dbapi_con.execute('pragma foreign_keys=ON')
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def configure_db():
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"""
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Establish the database, create an engine if needed, and
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register the models.
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"""
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global _ENGINE
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if not _ENGINE:
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sql_connection = cfg.CONF.DATABASE.sql_connection
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connection_dict = sql.engine.url.make_url(sql_connection)
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engine_args = {
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'pool_recycle': 3600,
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'echo': False,
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'convert_unicode': True,
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}
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if 'mysql' in connection_dict.drivername:
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engine_args['listeners'] = [MySQLPingListener()]
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if (MySQLdb is not None and
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cfg.CONF.DATABASE.sql_dbpool_enable):
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pool_args = {
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'db': connection_dict.database,
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'passwd': connection_dict.password or '',
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'host': connection_dict.host,
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'user': connection_dict.username,
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'min_size': cfg.CONF.DATABASE.sql_min_pool_size,
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'max_size': cfg.CONF.DATABASE.sql_max_pool_size,
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'max_idle': cfg.CONF.DATABASE.sql_idle_timeout
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}
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creator = db_pool.ConnectionPool(MySQLdb, **pool_args)
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engine_args['creator'] = creator.create
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if (MySQLdb is None and cfg.CONF.DATABASE.sql_dbpool_enable):
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LOG.warn(_("Eventlet connection pooling will not work without "
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"python-mysqldb!"))
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if 'sqlite' in connection_dict.drivername:
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engine_args['listeners'] = [SqliteForeignKeysListener()]
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if sql_connection == "sqlite://":
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engine_args["connect_args"] = {'check_same_thread': False}
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_ENGINE = create_engine(sql_connection, **engine_args)
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sql.event.listen(_ENGINE, 'checkin', greenthread_yield)
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if not register_models():
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if cfg.CONF.DATABASE.reconnect_interval:
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remaining = cfg.CONF.DATABASE.sql_max_retries
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reconnect_interval = cfg.CONF.DATABASE.reconnect_interval
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retry_registration(remaining, reconnect_interval)
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def clear_db(base=BASE):
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global _ENGINE, _MAKER
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assert _ENGINE
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unregister_models(base)
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if _MAKER:
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_MAKER.close_all()
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_MAKER = None
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_ENGINE.dispose()
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_ENGINE = None
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def get_session(autocommit=True, expire_on_commit=False):
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"""Helper method to grab session"""
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global _MAKER, _ENGINE
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if not _MAKER:
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assert _ENGINE
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_MAKER = sessionmaker(bind=_ENGINE,
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autocommit=autocommit,
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expire_on_commit=expire_on_commit)
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return _MAKER()
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def retry_registration(remaining, reconnect_interval, base=BASE):
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if remaining == -1:
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remaining = 'infinite'
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while True:
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if remaining != 'infinite':
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if remaining == 0:
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LOG.error(_("Database connection lost, exit..."))
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break
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remaining -= 1
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LOG.info(_("Unable to connect to database, %(remaining)s attempts "
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"left. Retrying in %(reconnect_interval)s seconds"),
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locals())
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time.sleep(reconnect_interval)
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if register_models(base):
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break
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def register_models(base=BASE):
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"""Register Models and create properties"""
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global _ENGINE
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assert _ENGINE
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try:
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base.metadata.create_all(_ENGINE)
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except sql.exc.OperationalError as e:
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LOG.info(_("Database registration exception: %s"), e)
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return False
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return True
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def unregister_models(base=BASE):
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"""Unregister Models, useful clearing out data before testing"""
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global _ENGINE
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assert _ENGINE
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base.metadata.drop_all(_ENGINE)
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def greenthread_yield(dbapi_con, con_record):
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"""
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Ensure other greenthreads get a chance to execute by forcing a context
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switch. With common database backends (eg MySQLdb and sqlite), there is
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no implicit yield caused by network I/O since they are implemented by
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C libraries that eventlet cannot monkey patch.
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"""
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greenthread.sleep(0)
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