RabbitMQ笔记(六)-BlockedListener

青旅半醒 2022-03-27 11:28 424阅读 0赞

BlockedListener 是监听连接阻塞情况的监听器

这个监听器在服务器内存报警或者硬盘报警的情况下，使用发送接口会产生阻塞，如果发送和接受等使用同一个连接，则会都阻塞，因此我们应该为消费者和生产者使用不同的CachingConnectionFactory，或者设置rabbitTemplate.setUsePublisherConnection(true);

#### BlockedListener的代码 ####

@Slf4j
    @Service
    public class RabbitBlockedListener implements BlockedListener {
        @Override
        public void handleBlocked(String s) throws IOException {
            log.info("=========================connection blocked, reason: {}", s);
        }
    
        @Override
        public void handleUnblocked() throws IOException {
            log.info("==============================connection unblocked");
        }
    }

#### 是在RabbitMQ connection连接上的时候设置进去的 ####

@Slf4j
    @Service
    public class RabbitConnectionListener implements ConnectionListener {
        @Autowired
        private RabbitBlockedListener rabbitBlockedListener;
        @Override
        public void onCreate(Connection connection) {
            log.info("================onCreate: {}", connection);
            connection.addBlockedListener(rabbitBlockedListener);
        }
    
        @Override
        public void onClose(Connection connection) {
            log.info("================onClose: {}", connection);
        }
    
        @Override
        public void onShutDown(ShutdownSignalException signal) {
            log.info("================onShutDown: {}", signal);
        }
    }

正常情况下，RabbitMQ的状态是这样的

![在这里插入图片描述][20190113143502400.jpg]

#### 测试内存报警 ####

RabbitMQ内存报警水位是由vm\_memory\_high\_watermark来控制的

在RabbitMQ使用 rabbitmqctl set\_vm\_memory\_high\_watermark 0.01

*  设置内存报警的水位，当内存使用达到了该水位时，RabbitMQ将产生报警
 *  可以通过rabbitmqctl status | grep vm\_memory\_high\_watermark查看当前的水位设置，默认时0.4

此时查看报警时的RabbitMQ的状态

![在这里插入图片描述][201901131435132.jpg]

此时往RabbitMQ发送一条消息，将会收到BlockedListener的消息，且reason会提示具体的错误原因

2019-01-09 23:49:53.408  INFO 73408 --- [xxxxxxx] c.m.demo.listener.RabbitBlockedListener  : =========================connection blocked, reason:low on memory

再将水位修改回来  
rabbitmqctl set\_vm\_memory\_high\_watermark 0.4

查看此时的程序的打印

2019-01-09 23:51:40.386  INFO 73408 --- [xxxxxxx] c.m.demo.listener.RabbitBlockedListener  : ==============================connection unblocked
    2019-01-09 2:351:40.396  INFO 73408 --- [xxxxxxx] c.m.d.l.i.ConfirmCallbackListenerImpl    : ConfirmCallbackListener thread:  CorrelationData: null, ack: true, cause: null
    2019-01-09 23:51:40.398  INFO 73408 --- [cTaskExecutor-4] com.mt.demo.rabbitmq.HelloListener2      : receive int msg: 30

#### 测试磁盘报警 ####

同样的修改磁盘的配置

##### rabbitmqctl set\_disk\_free\_limit 48G #####

*  设置空闲磁盘的大小，空闲值小于该值时产生报警，默认时48M
 *  也可以使用这个命令将磁盘和内存的大小关联起来设置 xx时磁盘和内存的配比 rabbitmqctl set\_disk\_free\_limit mem\_relative xx

此时查看RabbitMQ的控制台  
![在这里插入图片描述][20190113143526140.jpg]

此时往RabbitMQ发送一条消息，将会收到BlockedListener的消息，且reason会提示具体的错误原因

2019-01-09 23:58:17.318  INFO 49240 --- [xxxxxxx] c.m.demo.listener.RabbitBlockedListener  : =========================connection blocked, reason:low on disk

再将磁盘限制修改回来

##### rabbitmqctl set\_disk\_free\_limit 48M #####

2019-01-09 23:58:49.793  INFO 49240 --- [xxxxxxx] c.m.demo.listener.RabbitBlockedListener  : ==============================connection unblocked
    2019-01-09 23:58:49.801  INFO 49240 --- [xxxxxxx] c.m.d.l.i.ConfirmCallbackListenerImpl    : ConfirmCallbackListener thread:  CorrelationData: null, ack: true, cause: null
    2019-01-09 23:58:49.806  INFO 49240 --- [cTaskExecutor-3] com.mt.demo.rabbitmq.HelloListener2      : receive int msg: 30

#### 测试同时报警 ####

同时设置内存和磁盘报警  
![在这里插入图片描述][2019011314353976.jpg]  
发送消息到队列，则会在这个监听器产生报警信息。

2019-01-10 00:00:08.811  INFO 49240 --- [xxxxxxx] c.m.demo.listener.RabbitBlockedListener  : =========================connection blocked, reason:low on disk & memory

需要同时解除内存和磁盘的报警才会收到unblock的消息

2019-01-10 00:04:05.764  INFO 49240 --- [xxxxxxx] c.m.demo.listener.RabbitBlockedListener  : ==============================connection unblocked
    2019-01-10 00:04:05.765  INFO 49240 --- [xxxxxxx] c.m.d.l.i.ConfirmCallbackListenerImpl    : ConfirmCallbackListener thread:  CorrelationData: null, ack: true, cause: null
    2019-01-10 00:04:05.766  INFO 49240 --- [cTaskExecutor-2] com.mt.demo.rabbitmq.HelloListener2      : receive int msg: 30

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![在这里插入图片描述][70]

[20190113143502400.jpg]: /images/20220327/f9c8da9f76434a439825229ff515606a.png
[201901131435132.jpg]: /images/20220327/5d76af7b06b14e3d8b23683709c79056.png
[20190113143526140.jpg]: /images/20220327/9cb369aef63d4bacab65d920e1da4271.png
[2019011314353976.jpg]: /images/20220327/ddc8da2245354520a10eb2ce6de43ef0.png
[70]: /images/20220327/d945826b167149faa33d2ec35fd6e81c.png