全局 Window 自定义触发器上的 allowedLateness

Question

我已经为我的事件流创建了自定义触发器和处理函数。

DataStream<DynamoDBRow> dynamoDBRows =
    sensorEvents
        .keyBy("id")
        .window(GlobalWindows.create())
        .trigger(new MyCustomTrigger())
        .allowedLateness(Time.minutes(1)) # Note
        .process(new MyCustomWindowProcessFunction());

我的触发器基于事件参数。收到事件结束信号后，MyCustomWindowProcessFunction() 将应用于 window 元素。

@Slf4j
public class MyCustomTrigger extends Trigger<SensorEvent, GlobalWindow> {

  @Override
  public TriggerResult onElement(SensorEvent element, long timestamp, GlobalWindow window, TriggerContext ctx) throws Exception {

    if (element.isEventEnd() == true) {
      return TriggerResult.FIRE_AND_PURGE;
    }

    return TriggerResult.CONTINUE;
  }

  @Override
  public TriggerResult onProcessingTime(long time, GlobalWindow window, TriggerContext ctx) throws Exception {
    return TriggerResult.CONTINUE;
  }

  @Override
  public TriggerResult onEventTime(long time, GlobalWindow window, TriggerContext ctx) throws Exception {
    return TriggerResult.CONTINUE;
  }

  @Override
  public void clear(GlobalWindow window, TriggerContext ctx) throws Exception {}
}

传感器数据可能很少，即使在触发器之后也可能出现。所以我添加了 .allowedLateness(Time.minutes(1))，以确保在处理过程中不会遗漏这些事件。

就我而言，allowedLateness 不起作用。

查阅文件后，我发现了这个

如何在 GlobalWindow 中包含 allowedLateness？

注意: 我也试过设置环境时间特性

env.setStreamTimeCharacteristic(TimeCharacteristic.IngestionTime);

更新：20-02-2020

目前正在考虑以下方法。（目前没有工作）

@Slf4j
public class JourneyTrigger extends Trigger<SensorEvent, GlobalWindow> {

  private final long allowedLatenessMillis;

  public JourneyTrigger(Time allowedLateness) {
    this.allowedLatenessMillis = allowedLateness.toMilliseconds();
  }

  @Override
  public TriggerResult onElement(SensorEvent element, long timestamp, GlobalWindow window, TriggerContext ctx) throws Exception {

    if (element.isEventEnd() == true) {
      log.info("Timer started with allowedLatenessMillis " + allowedLatenessMillis);
      ctx.registerEventTimeTimer(System.currentTimeMillis() + allowedLatenessMillis);
    }

    return TriggerResult.CONTINUE;
  }

  @Override
  public TriggerResult onEventTime(long time, GlobalWindow window, TriggerContext ctx) throws Exception {
    log.info("onEvenTime called at "+System.currentTimeMillis() );
    return TriggerResult.FIRE_AND_PURGE;
  }


  @Override
  public TriggerResult onProcessingTime(long time, GlobalWindow window, TriggerContext ctx) throws Exception {
    return TriggerResult.CONTINUE;
  }

  @Override
  public void clear(GlobalWindow window, TriggerContext ctx) throws Exception {}
}

Answer 1

老实说，我没有理由在这里使用 GlobalWindow。您可以只使用与您的 Trigger 具有相同目的的 KeyedProcessFunction，基本上，它会将事件开始到事件结束的所有元素收集到 ListState然后当您收到 isEventEnd()==true 时，您可以简单地安排 EventTime 计时器，该计时器将在一分钟后触发并发出 ListState.

中收集的结果

Answer 2

最后，我能够使用下面的自定义触发器实现我的要求。

import lombok.extern.slf4j.Slf4j;
import org.apache.flink.streaming.api.windowing.time.Time;
import org.apache.flink.streaming.api.windowing.triggers.Trigger;
import org.apache.flink.streaming.api.windowing.triggers.TriggerResult;
import org.apache.flink.streaming.api.windowing.windows.GlobalWindow;

@Slf4j
public class JourneyTrigger extends Trigger<SensorEvent, GlobalWindow> {

  private final long allowedLatenessMillis;

  public JourneyTrigger(Time allowedLateness) {
    this.allowedLatenessMillis = allowedLateness.toMilliseconds();
  }

  @Override
  public TriggerResult onElement(SensorEvent element, long timestamp, GlobalWindow window, TriggerContext ctx) throws Exception {

    if (element.isEventEnd()==true) {
      log.info("Timer started with allowedLatenessMillis " + allowedLatenessMillis);
      ctx.registerProcessingTimeTimer(System.currentTimeMillis() + allowedLatenessMillis);
    }

    return TriggerResult.CONTINUE;
  }

  @Override
  public TriggerResult onProcessingTime(long time, GlobalWindow window, TriggerContext ctx) throws Exception {
    log.info("onProcessingTime called at "+System.currentTimeMillis() );
    return TriggerResult.FIRE_AND_PURGE;
  }

  @Override
  public TriggerResult onEventTime(long time, GlobalWindow window, TriggerContext ctx) throws Exception {
    return TriggerResult.CONTINUE;
  }



  @Override
  public void clear(GlobalWindow window, TriggerContext ctx) throws Exception {}
}

同样在Driver.javaclass，设置环境Time Characteristic

env.setStreamTimeCharacteristic(TimeCharacteristic.ProcessingTime);

全局 Window 自定义触发器上的 allowedLateness

allowedLateness on Global Window custom trigger

java

apache-flink

amazon-kinesis

amazon-kinesis-analytics