RabbitConnectionListener

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

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

image.png

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

image.png

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

image.png

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