Question

为进行简单的概念验证，我试图在两分钟的窗口中显示点击数据。我要从那里开始要做的就是打印每个窗口的计数，以及窗口到BigQuery的边界。在运行管道时，我不断收到以下错误：

org.apache.beam.sdk.Pipeline$PipelineExecutionException: java.lang.RuntimeException: java.io.IOException: Insert failed: [{"errors":[{"debugInfo":"","location":"windowend","message":"This field is not a record.","reason":"invalid"}],"index":0}]

管道如下所示：

// Creating the pipeline
Pipeline p = Pipeline.create(options);

// Window items
PCollection<TableRow> counts = p.apply("ReadFromPubSub", PubsubIO.readStrings().fromTopic(options.getTopic()))
.apply("AddEventTimestamps", WithTimestamps.of(TotalCountPipeline::ExtractTimeStamp).withAllowedTimestampSkew(Duration.standardDays(10000)))
        .apply("Window", Window.<String>into(
                FixedWindows.of(Duration.standardHours(options.getWindowSize())))
                .triggering(
                        AfterWatermark.pastEndOfWindow()
                                .withLateFirings(AfterPane.elementCountAtLeast(1)))
                .withAllowedLateness(Duration.standardDays(10000))
                .accumulatingFiredPanes())
        .apply("CalculateSum", Combine.globally(Count.<String>combineFn()).withoutDefaults())
        .apply("BigQueryFormat", ParDo.of(new FormatCountsFn()));

// Writing to BigQuery
counts.apply("WriteToBigQuery",BigQueryIO.writeTableRows()
                .to(options.getOutputTable())
                .withSchema(getSchema())
.withWriteDisposition(BigQueryIO.Write.WriteDisposition.WRITE_APPEND));

// Execute pipeline
p.run().waitUntilFinish();

我猜想它与BigQuery格式化功能有关，该功能实现如下：

static class FormatCountsFn extends DoFn<Long, TableRow> {
    @ProcessElement
    public void processElement(ProcessContext c, BoundedWindow window) {
        TableRow row =
                new TableRow()
                        .set("windowStart", window.maxTimestamp().toDateTime())
                        .set("count", c.element().intValue());
        c.output(row);
    }
}

受this post的启发。谁能对此有所启发？似乎无法绕开它。

Answer 1

显然，此问题的答案与光束窗口无关，并且仅与BigQuery有关。将DateTime对象写入BigQuery行需要使用正确的yyyy-MM-dd HH：mm：ss格式的字符串，这与我提供的DateTime对象相反。

梁：按窗口边界的每个窗口元素计数书写

1 个答案: