From cb0a2a059132721e8483e1090766611009deafad Mon Sep 17 00:00:00 2001 From: JUN JIE NAN Date: Thu, 12 Dec 2013 15:23:46 +0800 Subject: [PATCH] Enables db2 server disconnects to be handled pessimistically MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit A checkout listener can be added to sqlalchemy to be able to handle database disconnect pessimistically and avoid an error in the event of a DB restart or simply a temp connection issue due to network glitches. At the moment only mysql is enabled with this feature. This patch enables db2 as well. Sync oslo db.sqlalchemy from commit： bb4d7a2534f6087d828e22784dc263522d309592 Partial-Bug: #1231657 Change-Id: Ib89de07f004975528baffdfd19aae689b089a324 --- .../openstack/common/db/sqlalchemy/session.py | 25 ++++++++++++------- .../common/db/sqlalchemy/test_migrations.py | 11 ++++---- 2 files changed, 22 insertions(+), 14 deletions(-) diff --git a/heat/openstack/common/db/sqlalchemy/session.py b/heat/openstack/common/db/sqlalchemy/session.py index 397eaa38de..b8f4c832ca 100644 --- a/heat/openstack/common/db/sqlalchemy/session.py +++ b/heat/openstack/common/db/sqlalchemy/session.py @@ -601,18 +601,24 @@ def _thread_yield(dbapi_con, con_record): time.sleep(0) -def _ping_listener(dbapi_conn, connection_rec, connection_proxy): - """Ensures that MySQL connections checked out of the pool are alive. +def _ping_listener(engine, dbapi_conn, connection_rec, connection_proxy): + """Ensures that MySQL and DB2 connections are alive. Borrowed from: http://groups.google.com/group/sqlalchemy/msg/a4ce563d802c929f """ + cursor = dbapi_conn.cursor() try: - dbapi_conn.cursor().execute('select 1') - except dbapi_conn.OperationalError as ex: - if ex.args[0] in (2006, 2013, 2014, 2045, 2055): - LOG.warning(_('Got mysql server has gone away: %s'), ex) - raise sqla_exc.DisconnectionError("Database server went away") + ping_sql = 'select 1' + if engine.name == 'ibm_db_sa': + # DB2 requires a table expression + ping_sql = 'select 1 from (values (1)) AS t1' + cursor.execute(ping_sql) + except Exception as ex: + if engine.dialect.is_disconnect(ex, dbapi_conn, cursor): + msg = _('Database server has gone away: %s') % ex + LOG.warning(msg) + raise sqla_exc.DisconnectionError(msg) else: raise @@ -670,8 +676,9 @@ def create_engine(sql_connection, sqlite_fk=False): sqlalchemy.event.listen(engine, 'checkin', _thread_yield) - if 'mysql' in connection_dict.drivername: - sqlalchemy.event.listen(engine, 'checkout', _ping_listener) + if engine.name in ['mysql', 'ibm_db_sa']: + callback = functools.partial(_ping_listener, engine) + sqlalchemy.event.listen(engine, 'checkout', callback) elif 'sqlite' in connection_dict.drivername: if not CONF.sqlite_synchronous: sqlalchemy.event.listen(engine, 'connect', diff --git a/heat/openstack/common/db/sqlalchemy/test_migrations.py b/heat/openstack/common/db/sqlalchemy/test_migrations.py index 3118d0c68f..07350a6aee 100644 --- a/heat/openstack/common/db/sqlalchemy/test_migrations.py +++ b/heat/openstack/common/db/sqlalchemy/test_migrations.py @@ -17,6 +17,7 @@ import ConfigParser import functools import os +import subprocess import lockfile import sqlalchemy @@ -24,7 +25,6 @@ import sqlalchemy.exc from heat.openstack.common.gettextutils import _ from heat.openstack.common import log as logging -from heat.openstack.common import processutils from heat.openstack.common.py3kcompat import urlutils from heat.openstack.common import test @@ -158,13 +158,13 @@ class BaseMigrationTestCase(test.BaseTestCase): super(BaseMigrationTestCase, self).tearDown() def execute_cmd(self, cmd=None): - out, err = processutils.trycmd(cmd, shell=True, discard_warnings=True) - output = out or err + process = subprocess.Popen(cmd, shell=True, stdout=subprocess.PIPE, + stderr=subprocess.STDOUT) + output = process.communicate()[0] LOG.debug(output) - self.assertEqual('', err, + self.assertEqual(0, process.returncode, "Failed to run: %s\n%s" % (cmd, output)) - @_set_db_lock('pgadmin', 'tests-') def _reset_pg(self, conn_pieces): (user, password, database, host) = get_db_connection_info(conn_pieces) os.environ['PGPASSWORD'] = password @@ -186,6 +186,7 @@ class BaseMigrationTestCase(test.BaseTestCase): os.unsetenv('PGPASSWORD') os.unsetenv('PGUSER') + @_set_db_lock(lock_prefix='migration_tests-') def _reset_databases(self): for key, engine in self.engines.items(): conn_string = self.test_databases[key]