SkyWalking?自定义插件(Spring?RabbitMQ)具体分析过程

来源：jb51　　时间：2022/2/14 13:35:56　　对本文有异议

SkyWalking 自定义插件(Spring RabbitMQ) 官方

RabbitMQ插件问题

skywalking官方提供的RabbitMQ插件存在缺陷，其只针对RabbitMQ官方原生Client实现扩展，但我们在项目中一般不直接使用原生Client，而是使用Spring RabitMQ Client，因Spring RabitMQ Consumer中存在跨线程操作，导致跟踪ID断链。

具体分析过程

1.官方插件源码的拦截点是原生Consumer的handleDelivery方法，源码如下:

2.而Spring RabbitMQ消费者的默认实现是BlockingQueueConsumer, handleDelivery核心逻辑是把消息放到内部的BlockingQueue队列，不做真正的消费处理，因此拦截此处无法关联到消费者逻辑，源码如下

@Override
		public void handleDelivery(String consumerTag, Envelope envelope, AMQP.BasicProperties properties,
				byte[] body) {
		...
			try {
				if (BlockingQueueConsumer.this.abortStarted > 0) {
					if (!BlockingQueueConsumer.this.queue.offer(
							new Delivery(consumerTag, envelope, properties, body, this.queueName),
							BlockingQueueConsumer.this.shutdownTimeout, TimeUnit.MILLISECONDS)) {
 
						Channel channelToClose = super.getChannel();
						RabbitUtils.setPhysicalCloseRequired(channelToClose, true);
						// Defensive - should never happen
						BlockingQueueConsumer.this.queue.clear();
						if (!this.canceled) {
							RabbitUtils.cancel(channelToClose, consumerTag);
						}
						try {
							channelToClose.close();
						catch (@SuppressWarnings("unused") TimeoutException e) {
							// no-op
					}
				}
				else {
					BlockingQueueConsumer.this.queue
							.put(new Delivery(consumerTag, envelope, properties, body, this.queueName));
			}
			catch (@SuppressWarnings("unused") InterruptedException e) {
				Thread.currentThread().interrupt();
			catch (Exception e) {
				BlockingQueueConsumer.logger.warn("Unexpected exception during delivery", e);
		}

3.真正的消费处理在SimpleMessageListenerContainer，SimpleMessageListenerContainer继承Runnable接口，在其run方法中while循环调用mainLoop方法，整体调用链路为

4.SimpleMessageListenerContainer.run() -> SimpleMessageListenerContainer.mainLoop() -> SimpleMessageListenerContainer.receiveAndExecute() -> SimpleMessageListenerContainer.doReceiveAndExecute() -> AbstractMessageListenerContainer.executeListener()。最终在executeListener中执行消费逻辑

protected void executeListener(Channel channel, Object data) {
	...
		try {
      // 执行消费逻辑
			doExecuteListener(channel, data);
			if (sample != null) {
				this.micrometerHolder.success(sample, data instanceof Message
						? ((Message) data).getMessageProperties().getConsumerQueue()
						: queuesAsListString());
			}
		}
		catch (RuntimeException ex) {
		....
		}
	}