1. 确定您的用例所需的触发器类型。以下是Beam触发器类型的简要说明：

• 当所有窗口都有数据时启动窗口: AfterWatermark • 基于数据量的触发器： AfterCount • 基于处理时间的触发器： AfterProcessingTime • 基于事件时间的触发器： AfterWatermarkEarlyAndLate

2. 为您的Beam管道配置触发器。下面是一些不同触发器的示例：

当窗口内有10个元素时启动窗口，等待1分钟后关闭窗口

windowed_elements = (p | beam.Create(data) | beam.WindowInto(window.FixedWindows(60)) | beam.ParDo(MyTransformer()) | beam.ParDo(MyDoFn()) | beam.ParDo(MyFilter()) | beam.ParDo(MyMap()) | beam.CombineGlobally(beam.combiners.ToListCombineFn()) | beam.ParDo(MyFinalTransform()) | beam.WindowInto(window.FixedWindows(60), trigger=trigger.AfterCount(10)))

略过初始延迟5分钟，在任何水印时间之后触发

windowed_elements = (p | beam.Create(data) | beam.WindowInto(window.FixedWindows(60)) | beam.ParDo(MyTransformer()) | beam.ParDo(MyDoFn()) | beam.ParDo(MyFilter()) | beam.ParDo(MyMap()) | beam.CombineGlobally(beam.combiners.ToListCombineFn()) | beam.ParDo(MyFinalTransform()) | beam.WindowInto(window.FixedWindows(60), trigger=trigger.AfterWatermark( early=timestamps.EarliestFirst, late=timestamps.LatestFirst, watermark=timedelta(minutes=-5))))

基于事件时间，在窗口关闭之前等待30秒钟

windowed_elements = (p | beam.Create(data) | beam.WindowInto(window.FixedWindows(60)) | beam.ParDo(MyTransformer()) | beam.ParDo(MyDoFn())