async function getByLocalService(req, res) {
    const userId = req.query.userRelated ? req.user.id : null;
    const service = await gladys.service.getLocalServiceByName(req.params.service_name);
    const value = await gladys.variable.getValue(req.params.variable_key, service.id, userId);
    if (!value) {
      throw new NotFoundError('VARIABLE_NOT_FOUND');
    }
    res.json({
      value,
    });
  }
@api {get} /api/service/:service_name/variable/:variable_key Get service variable
@apiName GetVariableByService
@apiGroup Variable