def _check_and_init_version_control(meta):
try:
for table in ('schedules', 'schedule_metadata', 'jobs', 'job_metadata',
'job_faults', 'workers'):
assert table in meta.tables
# NOTE(venkatesh): if the existing db has already got the base tables,
# set the version for migration to '6' as the first six version_scripts
# are used for creating the base tables.
return version_control(6)
except AssertionError:
msg = _("Unable to get the db_version. Reason: Unknown DB State.")
raise exception.QonosException(msg)
def db_sync(version=None):
"""
Place a database under migration control and perform an upgrade
:retval version number
"""
if version is not None:
try:
version = int(version)
except ValueError:
raise exception.QonosException(_("version should be an integer"))
current_version = int(db_version())
if version is None or version > current_version:
return upgrade(version=version)
else:
return downgrade(version=version)
def __get_backend(self):
if not self.__backend:
if self.__config_group is None:
backend_name = CONF[self.__pivot]
else:
backend_name = CONF[self.__config_group][self.__pivot]
if backend_name not in self.__backends:
msg = _('Invalid backend: %s') % backend_name
raise exc.QonosException(msg)
backend = self.__backends[backend_name]
if isinstance(backend, tuple):
name = backend[0]
fromlist = backend[1]
else:
name = backend
fromlist = backend
self.__backend = __import__(name, None, None, fromlist)
return self.__backend