Device component:

def get_device_controller_uuid(device : Device) -> Optional[str]:

    controller_uuid = device.controller_id.device_uuid.uuid

    if len(controller_uuid) > 0: return controller_uuid

    #for config_rule in device.device_config.config_rules:

    #    if config_rule.WhichOneof('config_rule') != 'custom': continue

    #    if config_rule.custom.resource_key != '_controller': continue

    #    device_controller_id = json.loads(config_rule.custom.resource_value)

    #    return device_controller_id['uuid']

    return None

def populate_endpoints(

            _sub_device.device_type = resource_value['type']

            _sub_device.device_operational_status = resource_value['status']

            # Sub-devices should not have a driver assigned. Instead, they should have

            # a config rule specifying their controller.

            #_sub_device.device_drivers.extend(resource_value['drivers'])        # pylint: disable=no-member

            #controller_config_rule = _sub_device.device_config.config_rules.add()

            #controller_config_rule.action = ConfigActionEnum.CONFIGACTION_SET

            #controller_config_rule.custom.resource_key = '_controller'

            #controller = {'uuid': device_uuid, 'name': device_name}

            #controller_config_rule.custom.resource_value = json.dumps(controller, indent=0, sort_keys=True)

            # Sub-devices might not have a driver assigned.

            if 'drivers' in resource_value:

                drivers = resource_value['drivers']

                if isinstance(drivers, (list, set)):

                    _sub_device.device_drivers.extend(drivers)  # pylint: disable=no-member

                elif isinstance(drivers, (int, str)):

                    _sub_device.device_drivers.append(drivers)  # pylint: disable=no-member

                else:

                    MSG = 'Unsupported drivers definition in sub-device({:s}, {:s})'

                    raise Exception(MSG.format(str(resource_key), str(resource_value)))

            # Sub-devices should always have a controller associated.

            _sub_device.controller_id.device_uuid.uuid = device_uuid

            new_sub_devices[_sub_device_uuid] = _sub_device