google-cloud-dataflow - 当CoGroupByKey与CalendarWindows一起使用时，到Flatten的输入具有不兼容的窗口windowFns

TL； DR:
如何使用与CalendarWindows设置相同的窗口策略来CoGroupByKey一组PCollection？
LONG VERSION
我正在编写一个从两个不同的发布/订阅中读取的数据流管道，其中一个PCollections被拆分为一个PCollectionTuple，最后我尝试先join them in a CoGroupByKey，然后再将其保存在BigQuery中。
在管道测试期间，我的PCollections的窗口化策略是:

private static PCollection<KV<String, Long>> applyWindowsAndCount(final PCollection<KV<String, Long>> summary, final String OperationName){
    return summary
            .apply("Apply Windows " + OperationName, Window
                    .<KV<String, Long>>into(FixedWindows.of(Duration.standardMinutes(1)))
                    .discardingFiredPanes()
                    .withAllowedLateness(Duration.standardDays(1)))
            .apply("Count " + OperationName, Count.perKey());
}

我将它们设置为长度为1分钟的 FixedWindow，以便快速获得结果。
我的分组就像:

private static PCollection<KV<String, CoGbkResult>> MergeSummary(PCollection<KV<String, Long>> Avail, PCollection<KV<String, Long>> ValuationOK, PCollection<KV<String, Long>> ValuationKO){
    return KeyedPCollectionTuple.of(Util.AVAIL, Avail)
                                .and(Util.VALUATION_OK, ValuationOK)
                                .and(Util.VALUATION_KO, ValuationKO)
                                .apply("Merge Summary", CoGroupByKey.create());
}

当我在本地和云上进行测试时，它运行得很顺利，但是，当我使用实际生产值设置窗口时， CalendarWindows的日期为 1天，如下所示:

private static PCollection<KV<String, Long>> applyWindowsAndCount(final PCollection<KV<String, Long>> summary, final String OperationName){
        return summary
                .apply("Apply Windows " + OperationName, Window
                                .<KV<String, Long>>into(CalendarWindows.days(1).withTimeZone(DateTimeZone.UTC).withStartingDay(2016,9,20)) //Per day windowing.
                                .discardingFiredPanes()
                                .withAllowedLateness(Duration.standardDays(1))) //Accepts X days late data.
                .apply("Count " + OperationName, Count.perKey());
    }

然后，我什至无法编译代码，因为我收到如下消息:

Exception in thread "main" java.lang.IllegalStateException: Inputs to Flatten had incompatible window windowFns: com.google.cloud.dataflow.sdk.transforms.windowing.CalendarWindows$DaysWindows@6af9fcb2, com.google.cloud.dataflow.sdk.transforms.windowing.CalendarWindows$DaysWindows@6cce16f4
at com.google.cloud.dataflow.sdk.transforms.Flatten$FlattenPCollectionList.apply(Flatten.java:121)
at com.google.cloud.dataflow.sdk.transforms.Flatten$FlattenPCollectionList.apply(Flatten.java:105)
at com.google.cloud.dataflow.sdk.runners.PipelineRunner.apply(PipelineRunner.java:74)
at com.google.cloud.dataflow.sdk.runners.DataflowPipelineRunner.apply(DataflowPipelineRunner.java:413)
at com.google.cloud.dataflow.sdk.Pipeline.applyInternal(Pipeline.java:367)
at com.google.cloud.dataflow.sdk.Pipeline.applyTransform(Pipeline.java:274)
at com.google.cloud.dataflow.sdk.values.PCollectionList.apply(PCollectionList.java:175)
at com.google.cloud.dataflow.sdk.transforms.join.CoGroupByKey.apply(CoGroupByKey.java:124)
at com.google.cloud.dataflow.sdk.transforms.join.CoGroupByKey.apply(CoGroupByKey.java:74)
at com.google.cloud.dataflow.sdk.runners.PipelineRunner.apply(PipelineRunner.java:74)
at com.google.cloud.dataflow.sdk.runners.DataflowPipelineRunner.apply(DataflowPipelineRunner.java:413)
at com.google.cloud.dataflow.sdk.Pipeline.applyInternal(Pipeline.java:367)
at com.google.cloud.dataflow.sdk.Pipeline.applyTransform(Pipeline.java:290)
at com.google.cloud.dataflow.sdk.transforms.join.KeyedPCollectionTuple.apply(KeyedPCollectionTuple.java:116)

阅读文档后，我发现:

是否很清楚，数据流认为我的PCollection具有不兼容的窗口，但是，所有这些都使用我之前复制的函数来应用。因此，我如何CoGroupByKey一组具有CalendarWindows设置的相同窗口策略的PCollections？

最佳答案

看起来像是CalendarWindows中的错误；要解决此问题，您可以创建一个CalendarWindows对象，并将其用作每个PCollection的WindowFn，而不是为每个对象创建单独的CalendarWindows对象。