apollo-portal/src/main/java/com/ctrip/framework/apollo/portal/controller/AppController.java/AppController/findMissEnvs
class AppController:  @GetMapping("/{appId}/miss_envs")
  public MultiResponseEntity<String> findMissEnvs(@PathVariable String appId) {

    MultiResponseEntity<String> response = MultiResponseEntity.ok();
    for (Env env : portalSettings.getActiveEnvs()) {
      try {
        appService.load(env, appId);
      } catch (Exception e) {
        if (e instanceof HttpClientErrorException &&
            ((HttpClientErrorException) e).getStatusCode() == HttpStatus.NOT_FOUND) {
          response.addResponseEntity(RichResponseEntity.ok(env.toString()));
        } else {
          response.addResponseEntity(RichResponseEntity.error(HttpStatus.INTERNAL_SERVER_ERROR,
              String.format("load appId:%s from env %s error.", appId,
                  env)
                  + e.getMessage()));
        }
      }
    }

    return response;
  }