public void start()

in transports/transport-rest/transport-rest-vertx/src/main/java/org/apache/servicecomb/transport/rest/vertx/RestServerVerticle.java [83:127]
42 lines of code
5 McCabe index (conditional complexity)

  public void start(Promise<Void> startPromise) throws Exception {
    try {
      super.start();
      // 如果本地未配置地址，则表示不必监听，只需要作为客户端使用即可
      if (endpointObject == null) {
        LOGGER.warn("rest listen address is not configured, will not start.");
        startPromise.complete();
        return;
      }
      Router mainRouter = Router.router(vertx);
      mountAccessLogHandler(mainRouter);
      mountCorsHandler(mainRouter);
      initDispatcher(mainRouter);
      mountGlobalRestFailureHandler(mainRouter);
      HttpServer httpServer = createHttpServer();
      httpServer.requestHandler(mainRouter);
      httpServer.connectionHandler(connection -> {
        DefaultHttpServerMetrics serverMetrics = (DefaultHttpServerMetrics) ((ConnectionBase) connection).metrics();
        DefaultServerEndpointMetric endpointMetric = serverMetrics.getEndpointMetric();
        long connectedCount = endpointMetric.getCurrentConnectionCount();
        int connectionLimit = DynamicPropertyFactory.getInstance()
            .getIntProperty("servicecomb.rest.server.connection-limit", Integer.MAX_VALUE).get();
        if (connectedCount > connectionLimit) {
          connection.close();
          endpointMetric.onRejectByConnectionLimit();
        }
      });
      List<HttpServerExceptionHandler> httpServerExceptionHandlers =
          SPIServiceUtils.getAllService(HttpServerExceptionHandler.class);
      httpServer.exceptionHandler(e -> {
        if (e instanceof ClosedChannelException) {
          // This is quite normal in between browser and ege, so do not print out.
          LOGGER.debug("Unexpected error in server.{}", ExceptionUtils.getExceptionMessageWithoutTrace(e));
        } else {
          LOGGER.error("Unexpected error in server.{}", ExceptionUtils.getExceptionMessageWithoutTrace(e));
        }
        httpServerExceptionHandlers.forEach(httpServerExceptionHandler -> httpServerExceptionHandler.handle(e));
      });
      startListen(httpServer, startPromise);
    } catch (Throwable e) {
      // vert.x got some states that not print error and execute call back in VertexUtils.blockDeploy, we add a log our self.
      LOGGER.error("", e);
      throw e;
    }
  }