104 lines
3.0 KiB
Python
104 lines
3.0 KiB
Python
# -*- coding: utf-8 -*-
|
|
|
|
# vim: tabstop=4 shiftwidth=4 softtabstop=4
|
|
|
|
# Copyright (C) 2012 Yahoo! Inc. All Rights Reserved.
|
|
# Copyright (C) 2013 Rackspace Hosting All Rights Reserved.
|
|
#
|
|
# 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.
|
|
|
|
"""Session Handling for SQLAlchemy backend."""
|
|
|
|
import logging
|
|
|
|
import sqlalchemy.orm
|
|
import sqlalchemy.engine
|
|
import sqlalchemy.interfaces
|
|
import sqlalchemy
|
|
from sqlalchemy.pool import NullPool
|
|
|
|
from taskflow.db import api as db_api
|
|
|
|
LOG = logging.getLogger(__name__)
|
|
|
|
_ENGINE = None
|
|
_MAKER = None
|
|
|
|
|
|
def get_session(autocommit=True, expire_on_commit=True):
|
|
"""Return a SQLAlchemy session."""
|
|
global _MAKER
|
|
|
|
if _MAKER is None:
|
|
_MAKER = get_maker(get_engine(), autocommit, expire_on_commit)
|
|
return _MAKER()
|
|
|
|
|
|
def synchronous_switch_listener(dbapi_conn, connection_rec):
|
|
"""Switch sqlite connections to non-synchronous mode"""
|
|
dbapi_conn.execute("PRAGMA synchronous = OFF")
|
|
|
|
|
|
def ping_listener(dbapi_conn, connection_rec, connection_proxy):
|
|
"""
|
|
Ensures that MySQL connections checked out of the
|
|
pool are alive.
|
|
|
|
Borrowed from:
|
|
http://groups.google.com/group/sqlalchemy/msg/a4ce563d802c929f
|
|
"""
|
|
try:
|
|
dbapi_conn.cursor().execute('select 1')
|
|
except dbapi_conn.OperationalError, ex:
|
|
if ex.args[0] in (2006, 2013, 2014, 2045, 2055):
|
|
LOG.warn(_('Got mysql server has gone away: %s'), ex)
|
|
raise DisconnectionError("Database server went away")
|
|
else:
|
|
raise
|
|
|
|
|
|
def get_engine():
|
|
"""Return a SQLAlchemy engine."""
|
|
global _ENGINE
|
|
if _ENGINE is None:
|
|
connection_dict = sqlalchemy.engine.url.make_url(_get_sql_connection())
|
|
engine_args = {
|
|
"pool_recycle": _get_sql_idle_timeout(),
|
|
"echo": False,
|
|
"convert_unicode": True
|
|
}
|
|
|
|
if "sqlite" in connection_dict.drivername:
|
|
engine_args['poolclass'] = NullPool
|
|
|
|
_ENGINE = sqlalchemy.create_engine(_get_sql_connection(),
|
|
**engine_args)
|
|
|
|
#TODO: Check to make sure engine connected
|
|
|
|
return _ENGINE
|
|
|
|
|
|
def get_maker(engine, autocommit=True, expire_on_commit=False):
|
|
"Return a SQLAlchemy sessionmaker using the given engine."""
|
|
return sqlalchemy.orm.sessionmaker(bind=engine,
|
|
autocommit=autocommit,
|
|
expire_on_commit=expire_on_commit)
|
|
|
|
def _get_sql_connection():
|
|
return db_api.SQL_CONNECTION
|
|
|
|
|
|
def _get_sql_idle_timeout():
|
|
return db_api.SQL_IDLE_TIMEOUT
|