关于服务开启后Qos服务没启动问题排查

[yswwpp]

在使用qos的时候发现22222端口始终没有被监听，调试才知道是启动qos服务的时候报错了，缺少netty相关的包，但是从日志中没有任何迹象。分析代码，类org.apache.dubbo.qos.protocol.QosProtocolWrapper中方法

private void startQosServer(URL url) {
       if (!hasStarted.compareAndSet(false, true)) {
           return;
       }

       try {
           boolean qosEnable = Boolean.parseBoolean(url.getParameter(QOS_ENABLE,"true"));
           if (!qosEnable) {
               return;
           }

           int port = Integer.parseInt(url.getParameter(QOS_PORT,"22222"));
           boolean acceptForeignIp = Boolean.parseBoolean(url.getParameter(ACCEPT_FOREIGN_IP,"true"));
           Server server = Server.getInstance();
           server.setPort(port);
           server.setAcceptForeignIp(acceptForeignIp);
           server.start();

       } catch (Throwable throwable) {
           //throw new RpcException("fail to start qos server", throwable);
       }
   }

其中 java Server server = Server.getInstance(); 报错之后，到catch中，结果日志也没有、异常也没上抛！！！
报错的那段代码虽然简单，但是有netty的依赖关系，所以还是存在报错的可能，建议此处catch之后打印一个警告级别的日志，用户可以清晰的看到为什么qos服务没有启动。

[chutian52]

异常没有上抛应该是认为qos功能不影响dubbo使用吧？毕竟QOS只是个增强型的plugin

[web1992]

It`s bug

[ralf0131]

Hi,

Could you please send a pull request to fix it?
I think it is a trivial change. I am going to a good first issue label.

[carryxyh]

@yswwpp

This problem has been fixed by this pr:
#2153

Is there any other questions for this issue? If not, we will close it soon. :)

[diecui1202]

@ralf0131 Does #2153 need to merge back to 2.6.x?

[ralf0131]

I think so. @diecui1202 I can do the back port