143 lines
4.2 KiB
Python
143 lines
4.2 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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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.orm import sessionmaker, exc
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from quantum.db import model_base
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from quantum.openstack.common import log as logging
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LOG = logging.getLogger(__name__)
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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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def configure_db(options):
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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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:param options: Mapping of configuration options
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"""
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global _ENGINE
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if not _ENGINE:
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connection_dict = sql.engine.url.make_url(options['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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_ENGINE = create_engine(options['sql_connection'], **engine_args)
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base = options.get('base', BASE)
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if not register_models(base):
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if 'reconnect_interval' in options:
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remaining = options.get('sql_max_retries', -1)
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reconnect_interval = options['reconnect_interval']
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retry_registration(remaining, reconnect_interval, base)
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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, %s attempts left. "
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"Retrying in %s seconds" % (remaining, reconnect_interval))
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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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