google-cloud-dataflow - 使用 InProcessPipelineRunner 执行时，PubsubReader 因 NullPointerException 而失败

Question

我有一个简单的管道，它只执行读取 PubsubIO.Read.subscription。在消耗了大约 200 个元素后，每次运行都会失败，但出现以下异常:

[error] (run-main-0) java.lang.RuntimeException: java.lang.NullPointerException
java.lang.RuntimeException: java.lang.NullPointerException
    at  com.google.cloud.dataflow.sdk.runners.inprocess.InProcessPipelineRunner.run(InProcessPipelineRunner.java:281)
    at com.google.cloud.dataflow.sdk.runners.inprocess.InProcessPipelineRunner.run(InProcessPipelineRunner.java:69)
    at com.google.cloud.dataflow.sdk.Pipeline.run(Pipeline.java:181)
    at com.sandbox.WriteLogsToBQ.main(WriteLogsToBQ.java:296)
    at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
    at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:62)
    at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43)
    at java.lang.reflect.Method.invoke(Method.java:498)
Caused by: java.lang.NullPointerException
    at com.google.cloud.dataflow.sdk.io.PubsubUnboundedSource$PubsubReader.ackBatch(PubsubUnboundedSource.java:612)
    at com.google.cloud.dataflow.sdk.io.PubsubUnboundedSource$PubsubCheckpoint.finalizeCheckpoint(PubsubUnboundedSource.java:297)
    at com.google.cloud.dataflow.sdk.runners.inprocess.UnboundedReadEvaluatorFactory$UnboundedReadEvaluator.startReader(UnboundedReadEvaluatorFactory.java:203)
    at com.google.cloud.dataflow.sdk.runners.inprocess.UnboundedReadEvaluatorFactory$UnboundedReadEvaluator.finishBundle(UnboundedReadEvaluatorFactory.java:172)
    at com.google.cloud.dataflow.sdk.runners.inprocess.TransformExecutor.finishBundle(TransformExecutor.java:163)
    at com.google.cloud.dataflow.sdk.runners.inprocess.TransformExecutor.run(TransformExecutor.java:119)
    at java.util.concurrent.Executors$RunnableAdapter.call(Executors.java:511)
    at java.util.concurrent.FutureTask.run(FutureTask.java:266)
    at java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1142)
    at java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:617)
    at java.lang.Thread.run(Thread.java:745)

我使用的是 SDK 版本 1.9.0。这在 1.6.1 中没有发生(成功获取 >10k 元素)。有谁知道解决方法？我还注意到 1.9.0 的获取速度比 1.6.1 快得多。对于 1.6.1，它似乎使用 10 个元素的批处理。

---

测试阅读形式主题:

p.apply(PubsubIO.Read.named("reading_topic_test").topic("projects/***/topics/SL_LogLogin"))

订阅是自动生成的，但是管道失败了:

Jan 05, 2017 2:06:33 PM com.google.cloud.dataflow.sdk.io.PubsubUnboundedSource apply
WARNING: Created subscription null to topic NestedValueProvider{value=NestedValueProvider{value=StaticValueProvider{value=projects/***/topics/SL_LogLogin}}}. 
Note this subscription WILL NOT be deleted when the pipeline terminates
[error] (run-main-0) com.google.cloud.dataflow.sdk.transforms.display.DisplayData$InternalBuilder$PopulateDisplayDataException: 
Error while populating display data for component:com.google.cloud.dataflow.sdk.io.PubsubUnboundedSource$StatsFn
com.google.cloud.dataflow.sdk.transforms.display.DisplayData$InternalBuilder$PopulateDisplayDataException: 
Error while populating display data for component: com.google.cloud.dataflow.sdk.io.PubsubUnboundedSource$StatsFn
    at    com.google.cloud.dataflow.sdk.transforms.display.DisplayData$InternalBuilder.include(DisplayData.java:664)
    at com.google.cloud.dataflow.sdk.transforms.display.DisplayData$InternalBuilder.include(DisplayData.java:643)
    at com.google.cloud.dataflow.sdk.transforms.display.DisplayData$InternalBuilder.include(DisplayData.java:637)
    at com.google.cloud.dataflow.sdk.transforms.ParDo.populateDisplayData(ParDo.java:1266)
    at com.google.cloud.dataflow.sdk.transforms.ParDo.access$200(ParDo.java:457)
    at com.google.cloud.dataflow.sdk.transforms.ParDo$Bound.populateDisplayData(ParDo.java:816)
    at com.google.cloud.dataflow.sdk.transforms.display.DisplayData$InternalBuilder.include(DisplayData.java:657)
    at com.google.cloud.dataflow.sdk.transforms.display.DisplayData$InternalBuilder.include(DisplayData.java:643)
    at com.google.cloud.dataflow.sdk.transforms.display.DisplayData$InternalBuilder.include(DisplayData.java:637)
    at com.google.cloud.dataflow.sdk.transforms.display.DisplayData$InternalBuilder.forRoot(DisplayData.java:630)
    at com.google.cloud.dataflow.sdk.transforms.display.DisplayData$InternalBuilder.access$000(DisplayData.java:617)
    at com.google.cloud.dataflow.sdk.transforms.display.DisplayData.from(DisplayData.java:76)
    at com.google.cloud.dataflow.sdk.runners.inprocess.DisplayDataValidator.evaluateDisplayData(DisplayDataValidator.java:47)
    at com.google.cloud.dataflow.sdk.runners.inprocess.DisplayDataValidator.access$100(DisplayDataValidator.java:29)
    at com.google.cloud.dataflow.sdk.runners.inprocess.DisplayDataValidator$Visitor.visitTransform(DisplayDataValidator.java:62)
    at com.google.cloud.dataflow.sdk.runners.TransformTreeNode.visit(TransformTreeNode.java:221)
    at com.google.cloud.dataflow.sdk.runners.TransformTreeNode.visit(TransformTreeNode.java:217)
    at com.google.cloud.dataflow.sdk.runners.TransformTreeNode.visit(TransformTreeNode.java:217)
    at com.google.cloud.dataflow.sdk.runners.TransformTreeNode.visit(TransformTreeNode.java:217)
    at com.google.cloud.dataflow.sdk.runners.TransformHierarchy.visit(TransformHierarchy.java:103)
    at com.google.cloud.dataflow.sdk.Pipeline.traverseTopologically(Pipeline.java:260)
    at com.google.cloud.dataflow.sdk.runners.inprocess.DisplayDataValidator.validateTransforms(DisplayDataValidator.java:43)
    at com.google.cloud.dataflow.sdk.runners.inprocess.DisplayDataValidator.validatePipeline(DisplayDataValidator.java:35)
    at com.google.cloud.dataflow.sdk.runners.inprocess.InProcessPipelineRunner.run(InProcessPipelineRunner.java:245)
    at com.google.cloud.dataflow.sdk.runners.inprocess.InProcessPipelineRunner.run(InProcessPipelineRunner.java:69)
    at com.google.cloud.dataflow.sdk.Pipeline.run(Pipeline.java:181)
    at com.sandbox.WriteLogsToBQ.main(WriteLogsToBQ.java:303)
    at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
    at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:62)
    at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43)
    at java.lang.reflect.Method.invoke(Method.java:498)
Caused by: java.lang.NullPointerException: Input display value cannot be null
    at com.google.cloud.dataflow.sdk.repackaged.com.google.common.base.Preconditions.checkNotNull(Preconditions.java:228)
    at com.google.cloud.dataflow.sdk.transforms.display.DisplayData$InternalBuilder.addItemIf(DisplayData.java:707)
    at com.google.cloud.dataflow.sdk.transforms.display.DisplayData$InternalBuilder.add(DisplayData.java:685)
    at com.google.cloud.dataflow.sdk.io.PubsubUnboundedSource$StatsFn.populateDisplayData(PubsubUnboundedSource.java:1147)
    at com.google.cloud.dataflow.sdk.transforms.display.DisplayData$InternalBuilder.include(DisplayData.java:657)
    at com.google.cloud.dataflow.sdk.transforms.display.DisplayData$InternalBuilder.include(DisplayData.java:643)
    at com.google.cloud.dataflow.sdk.transforms.display.DisplayData$InternalBuilder.include(DisplayData.java:637)
    at com.google.cloud.dataflow.sdk.transforms.ParDo.populateDisplayData(ParDo.java:1266)
    at com.google.cloud.dataflow.sdk.transforms.ParDo.access$200(ParDo.java:457)
    at com.google.cloud.dataflow.sdk.transforms.ParDo$Bound.populateDisplayData(ParDo.java:816)
    at com.google.cloud.dataflow.sdk.transforms.display.DisplayData$InternalBuilder.include(DisplayData.java:657)
    at com.google.cloud.dataflow.sdk.transforms.display.DisplayData$InternalBuilder.include(DisplayData.java:643)
    at com.google.cloud.dataflow.sdk.transforms.display.DisplayData$InternalBuilder.include(DisplayData.java:637)
    at com.google.cloud.dataflow.sdk.transforms.display.DisplayData$InternalBuilder.forRoot(DisplayData.java:630)
    at com.google.cloud.dataflow.sdk.transforms.display.DisplayData$InternalBuilder.access$000(DisplayData.java:617)
    at com.google.cloud.dataflow.sdk.transforms.display.DisplayData.from(DisplayData.java:76)
    at com.google.cloud.dataflow.sdk.runners.inprocess.DisplayDataValidator.evaluateDisplayData(DisplayDataValidator.java:47)
    at com.google.cloud.dataflow.sdk.runners.inprocess.DisplayDataValidator.access$100(DisplayDataValidator.java:29)
    at com.google.cloud.dataflow.sdk.runners.inprocess.DisplayDataValidator$Visitor.visitTransform(DisplayDataValidator.java:62)
    at com.google.cloud.dataflow.sdk.runners.TransformTreeNode.visit(TransformTreeNode.java:221)
    at com.google.cloud.dataflow.sdk.runners.TransformTreeNode.visit(TransformTreeNode.java:217)
    at com.google.cloud.dataflow.sdk.runners.TransformTreeNode.visit(TransformTreeNode.java:217)
    at com.google.cloud.dataflow.sdk.runners.TransformTreeNode.visit(TransformTreeNode.java:217)
    at com.google.cloud.dataflow.sdk.runners.TransformHierarchy.visit(TransformHierarchy.java:103)
    at com.google.cloud.dataflow.sdk.Pipeline.traverseTopologically(Pipeline.java:260)
    at com.google.cloud.dataflow.sdk.runners.inprocess.DisplayDataValidator.validateTransforms(DisplayDataValidator.java:43)
    at com.google.cloud.dataflow.sdk.runners.inprocess.DisplayDataValidator.validatePipeline(DisplayDataValidator.java:35)
    at com.google.cloud.dataflow.sdk.runners.inprocess.InProcessPipelineRunner.run(InProcessPipelineRunner.java:245)
    at com.google.cloud.dataflow.sdk.runners.inprocess.InProcessPipelineRunner.run(InProcessPipelineRunner.java:69)
    at com.google.cloud.dataflow.sdk.Pipeline.run(Pipeline.java:181)
    at com.sandbox.WriteLogsToBQ.main(WriteLogsToBQ.java:303)
    at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
    at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:62)
    at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43)
    at java.lang.reflect.Method.invoke(Method.java:498)

Answer 1

这由 https://github.com/GoogleCloudPlatform/DataflowJavaSDK/pull/547 解决.很抱歉给您带来麻烦。

根本原因是 incubator-beam 和 GoogleDataflowSDK 之间的反向移植错误，未能初始化在按作业订阅的情况下返回的订阅。