Spring 集成 - 轮询器触发太频繁

编程问答 2022-04-21

问题描述

我有以下代码：

@Bean
  public IntegrationFlow aggregatingFlow(
      AmqpInboundChannelAdapter aggregatorInboundAdapter,PollableChannel aggregatingChannel,AmqpOutboundEndpointEnhanced amqpOutboundEndpoint,PollSkipAdvice pollSkipAdvice) {
    return IntegrationFlows.from(aggregatorInboundAdapter)
        .wireTap(wtChannel())
        .channel(aggregatingChannel)
        .handle(
            amqpOutboundEndpoint,e ->
                e.poller(
                        Pollers.fixedDelay(1,TimeUnit.SECONDS,1)
                            .maxMessagesPerPoll(DEFAULT_MESSAGES_PER_POLL)
                            .advice(pollSkipAdvice))
                    .id("pollingConsumer"))
        .get();
  }

这里 pollSkipAdvice 被定义为

@Bean
  public PollSkipAdvice pollSkipAdvice() {
    return new PollSkipAdvice(
        new PollSkipStrategy() {
          int currentPoll = 1;

          @Override
          public synchronized boolean skipPoll() {
            int hitRate = 0; //just not to add to the code; its dynamic
            if (currentPoll >= hitRate) {
              System.out.println(messageformat.format("{0} : Hit poll number {1} for message number of {2} | {3}",DateTimeFormatter.ofPattern("HH:mm:ss. SSS")
                      .withZone(ZoneOffset.UTC)
                      .format(Instant.Now()),currentPoll,currentMessagesInQueue,Thread.currentThread().getName()));
              currentPoll = 1;
              return false;
            }
            currentPolL++;
            return true;
          }
        });
  }

我面临的问题是 Poller 每秒被调用多次。这是我在测试代码时得到的日志：

21:41:47. 652 : Hit poll number 1 for message number of 0 | pool-3-thread-1
21:41:47. 654 : Hit poll number 1 for message number of 0 | pool-3-thread-1
EventChange(id=190)
21:41:47. 656 : Hit poll number 1 for message number of 0 | pool-3-thread-1
EventChange(id=191)
21:41:47. 658 : Hit poll number 1 for message number of 0 | pool-3-thread-1
21:41:47. 660 : Hit poll number 1 for message number of 0 | pool-3-thread-1
EventChange(id=192)
21:41:47. 662 : Hit poll number 1 for message number of 0 | pool-3-thread-1
EventChange(id=193)
21:41:47. 665 : Hit poll number 1 for message number of 0 | pool-3-thread-1
EventChange(id=194)
21:41:47. 667 : Hit poll number 1 for message number of 0 | pool-3-thread-1
EventChange(id=195)
21:41:47. 669 : Hit poll number 1 for message number of 0 | pool-3-thread-1
21:41:47. 671 : Hit poll number 1 for message number of 0 | pool-3-thread-1
EventChange(id=196)
EventChange(id=197)
EventChange(id=198)
EventChange(id=199)
21:41:48. 653 : Hit poll number 1 for message number of 0 | pool-3-thread-1
21:41:49. 656 : Hit poll number 1 for message number of 0 | pool-3-thread-1
21:41:50. 659 : Hit poll number 1 for message number of 0 | pool-3-thread-1
21:41:51. 661 : Hit poll number 1 for message number of 0 | pool-3-thread-1
21:41:52. 662 : Hit poll number 1 for message number of 0 | pool-3-thread-1

所以似乎每当我从 AMQP 收到一些东西时，这个 Poller 就会触发很多次。您可以在日志中看到 21:41:47. 652 到 21:41:47. 671 在 1 秒内触发了 10 次。另一方面，一旦它结束 - 它就会正常工作（每秒一次）。

当我尝试为这两种情况打印堆栈跟踪时，只有几毫秒的距离，我得到了这个：

20:32:56. 406 : Hit poll number 2 for message number of 0 | pool-3-thread-1

java.lang.Thread.getStackTrace(Thread.java:1559)
com.a.configuration.component.EventAggregatorConfig$1.skipPoll(EventAggregatorConfig.java:313)
org.springframework.integration.scheduling.PollSkipAdvice.invoke(PollSkipAdvice.java:51)
org.springframework.aop.framework.ReflectiveMethodInvocation.proceed(ReflectiveMethodInvocation.java:186)
org.springframework.aop.framework.JdkDynamicAopProxy.invoke(JdkDynamicAopProxy.java:212)
com.sun.proxy.$Proxy136.call(UnkNown Source)
org.springframework.integration.endpoint.AbstractPollingEndpoint.pollForMessage(AbstractPollingEndpoint.java:328)
org.springframework.integration.endpoint.AbstractPollingEndpoint.lambda$null$1(AbstractPollingEndpoint.java:275)
org.springframework.integration.util.ErrorHandlingTaskExecutor.lambda$execute$0(ErrorHandlingTaskExecutor.java:57)
java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1149)
java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:624)
java.lang.Thread.run(Thread.java:748)

20:32:56. 408 : Hit poll number 1 for message number of 0 | pool-3-thread-1

java.lang.Thread.getStackTrace(Thread.java:1559)
com.a.configuration.component.EventAggregatorConfig$1.skipPoll(EventAggregatorConfig.java:313)
org.springframework.integration.scheduling.PollSkipAdvice.invoke(PollSkipAdvice.java:51)
org.springframework.aop.framework.ReflectiveMethodInvocation.proceed(ReflectiveMethodInvocation.java:186)
org.springframework.aop.framework.JdkDynamicAopProxy.invoke(JdkDynamicAopProxy.java:212)
com.sun.proxy.$Proxy136.call(UnkNown Source)
org.springframework.integration.endpoint.AbstractPollingEndpoint.pollForMessage(AbstractPollingEndpoint.java:328)
org.springframework.integration.endpoint.AbstractPollingEndpoint.lambda$null$1(AbstractPollingEndpoint.java:275)
org.springframework.integration.util.ErrorHandlingTaskExecutor.lambda$execute$0(ErrorHandlingTaskExecutor.java:57)
java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1149)
java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:624)
java.lang.Thread.run(Thread.java:748)

我是否以错误的方式配置了它？我试图定义单独的 taskScheduler，但它似乎根本没有使用那个。

更新

大概经过一番分析，有可能是spring AbstractPollingEndpoint类中的这部分造成的：

while (this.initialized && (this.maxMessagesPerPoll <= 0 || count < this.maxMessagesPerPoll)) {
                        if (pollForMessage() == null) {
                            break;
                        }
                        count++;
                    }

所以基本上即使我说每 1 秒轮询一次，如果有的话就取 10 条消息；但是如果没有消息，什么都不做 - 如果什么也没找到，它会继续尝试轮询？

更新2

是的，似乎每次消息轮询都会调用 skipPoll 建议，而不是 maxMessagesPerPoll 一次。

解决方法

我不确定问题是什么。逻辑绝对是我们从这条建议中所期望的：

private Runnable createPoller() {
    return () ->
            this.taskExecutor.execute(() -> {
                int count = 0;
                while (this.initialized && (this.maxMessagesPerPoll <= 0 || count < this.maxMessagesPerPoll)) {
                    if (this.maxMessagesPerPoll == 0) {
                        logger.info("Polling disabled while 'maxMessagesPerPoll == 0'");
                        break;
                    }
                    if (pollForMessage() == null) {
                        break;
                    }
                    count++;
                }
            });
}

因此，如果 pollForMessage() 返回 null，我们将中断 while() 循环并退出当前轮询周期。当 null 返回 PollSkipAdvice 时，PollSkipStrategy 从 false 发生。

您可能只是误解了轮询周期并真正进行了轮询。第一个确实是触发器命中时间及其maxMessagesPerPoll的时刻。真正的 poll 确实是关于单个 pollForMessage 调用。您可能需要修改自定义策略的逻辑，以满足应用此类建议的现有要求。

javajavaspring-amqpspring-integration