apollo-configservice/src/main/java/com/ctrip/framework/apollo/metaservice/controller/ServiceController.java/ServiceController/getConfigService
class ServiceController:  @RequestMapping("/config")
  public List<ServiceDTO> getConfigService(
      @RequestParam(value = "appId", defaultValue = "") String appId,
      @RequestParam(value = "ip", required = false) String clientIp) {
    return discoveryService.getServiceInstances(ServiceNameConsts.APOLLO_CONFIGSERVICE);
  }