Public bug reported: I found out that some methods like _create_ha_interfaces https://github.com/openstack/neutron/blob/master/neutron/db/l3_hamode_db.py#L329-L345 contain the following logic:
def create(): create_something() try: _do_other_thing() except Exception: with excutils.save_and_reraise_exception(): delete_something() def _do_other_thing(): with context.session.begin(subtransactions=True): .... The problem is that when exception is raised in _do_other_thing it is caught in except block, but the object cannot be deleted in except section because internal transaction has been rolled back. We have tests on these methods, but they also are not correct (for example https://github.com/openstack/neutron/blob/master/neutron/tests/unit/db/test_l3_hamode_db.py#L360-L377) as methods _do_other_thing() are mocked so inside transaction is never created and aborted. The possible solution is to use nested transaction in such places like this: def create() with context.session.begin(subtransactions=True): create_something() try: _do_other_thing() except Exception: with excutils.save_and_reraise_exception(): delete_something() def _do_other_thing(): with context.session.begin(nested=True): .... ** Affects: neutron Importance: Undecided Assignee: Ann Kamyshnikova (akamyshnikova) Status: New ** Tags: db -- You received this bug notification because you are a member of Yahoo! Engineering Team, which is subscribed to neutron. https://bugs.launchpad.net/bugs/1501686 Title: Incorrect exception handling in DB code involving rollbacked transactions. Status in neutron: New Bug description: I found out that some methods like _create_ha_interfaces https://github.com/openstack/neutron/blob/master/neutron/db/l3_hamode_db.py#L329-L345 contain the following logic: def create(): create_something() try: _do_other_thing() except Exception: with excutils.save_and_reraise_exception(): delete_something() def _do_other_thing(): with context.session.begin(subtransactions=True): .... The problem is that when exception is raised in _do_other_thing it is caught in except block, but the object cannot be deleted in except section because internal transaction has been rolled back. We have tests on these methods, but they also are not correct (for example https://github.com/openstack/neutron/blob/master/neutron/tests/unit/db/test_l3_hamode_db.py#L360-L377) as methods _do_other_thing() are mocked so inside transaction is never created and aborted. The possible solution is to use nested transaction in such places like this: def create() with context.session.begin(subtransactions=True): create_something() try: _do_other_thing() except Exception: with excutils.save_and_reraise_exception(): delete_something() def _do_other_thing(): with context.session.begin(nested=True): .... To manage notifications about this bug go to: https://bugs.launchpad.net/neutron/+bug/1501686/+subscriptions -- Mailing list: https://launchpad.net/~yahoo-eng-team Post to : yahoo-eng-team@lists.launchpad.net Unsubscribe : https://launchpad.net/~yahoo-eng-team More help : https://help.launchpad.net/ListHelp