Xiu Shi created BEAM-4301:
-----------------------------
Summary: NullPointerException with ValueState of custom class
Key: BEAM-4301
URL: https://issues.apache.org/jira/browse/BEAM-4301
Project: Beam
Issue Type: Bug
Components: sdk-java-core
Affects Versions: 2.4.0
Reporter: Xiu Shi
Assignee: Kenneth Knowles
This is an issue introduced by Beam version 2.4.0, which breaks my current
implementation of stateful processing during unit test with direct runner.
I'm write a DoFn that has a `ValueState` of a custom class which acts as
caching. In short, the first item will run through the DoFn just fine, then
NullPointerException will be thrown before the second item reaches the DoFn. If
I switch to `ValueState` of a string, then everything works fine.
A simplified version of the DoFn looks like the following:
{code:java}
public class GetPredictionsFn
extends DoFn<KV<List<String>, String>, KV<String, ArrayList<String>>> {
@StateId("cache")
private final StateSpec<ValueState<PredictionResponseDto>> cache =
StateSpecs.value(AvroCoder.of(PredictionResponseDto.class));
...
@ProcessElement
public void processElement(ProcessContext c,
@StateId("cache") ValueState<PredictionResponseDto> cache
)
throws IOException {
Gson gson = new Gson();
System.out.println("here");
List<String> contentIds = c.element().getKey();
String sessionId = c.element().getValue();
System.out.println(sessionId);
ArrayList<String> strItems = null;
try {
PredictionResponseDto parsedResponse = cache.read();
// strItems = parsedResponse.getStrItems();
if (parsedResponse == null) {
throw new RuntimeException();
}
System.out.println("read");
System.out.println(gson.toJson(parsedResponse));
}
catch (Exception e) {
String jsonStr =
"{\"predictions\":[{\"output\":[19]}],\"strItems\":[\"1.9\"],\"timestamp\":1526485646091}";
PredictionResponseDto parsedResponse =
PredictionResponseDto.parseJson(jsonStr);
strItems = parsedResponse.getStrItems();
System.out.println("write");
System.out.println(gson.toJson(parsedResponse));
System.out.println(gson.toJson(strItems));
cache.write(parsedResponse);
PredictionResponseDto parsedResponse1 = cache.read();
System.out.println(gson.toJson(parsedResponse1));
}
KV<String, ArrayList<String>> predictionKv = KV.of(sessionId, strItems);
System.out.println(gson.toJson(predictionKv));
c.output(predictionKv);
}
}
{code}
And the test pipeline looks like the following:
{code:java}
// Create a test pipeline.
Pipeline p = Pipeline.create();
// Create timestamps
// currentTime need to be set to the past, otherwise the first window will not
be set to
// currentTime + expiry, but creation time of the pipeline + expiry.
Instant currentTime = new Instant(0L);
Instant onTime = currentTime
.plus(Duration.standardSeconds(streamingOptions.getCacheExpiry()))
.minus(Duration.standardSeconds(1));
Instant lateTime = currentTime
.plus(Duration.standardSeconds(streamingOptions.getCacheExpiry()))
.plus(Duration.standardSeconds(1));
// Create stream input.
TestStream<KV<List<String>, String>> events =
TestStream.create(KvCoder.of(ListCoder.of(
StringUtf8Coder.of()), StringUtf8Coder.of()))
// set the next timestamp to be currentTime
.advanceWatermarkTo(currentTime)
.addElements(KV.of(Arrays.asList("1"), "1"))
.advanceWatermarkTo(onTime)
.addElements(KV.of(Arrays.asList("1"), "2"))
.addElements(KV.of(Arrays.asList("1"), "3"))
.advanceWatermarkTo(lateTime)
.addElements(KV.of(Arrays.asList("1"), "4"))
.advanceWatermarkToInfinity();
PCollection<KV<String, ArrayList<String>>> output =
p.apply(events).apply(Window.into(FixedWindows.of(
Duration.standardSeconds(streamingOptions.getCacheExpiry()))))
.apply(ParDo.of(doFn));
PAssert.that(output).containsInAnyOrder(expect);
{code}
The Trace looks like:
{code:java}
org.apache.beam.sdk.Pipeline$PipelineExecutionException:
java.lang.NullPointerException: in ca.cbc.recsysdataflow.PredictionResponseDto
in array in ca.cbc.recsysdataflow.PredictionResponseDto$.Prediction in array
null of array in field key of
ca.cbc.recsysdataflow.PredictionResponseDto$.Prediction of array in field
predictions of ca.cbc.recsysdataflow.PredictionResponseDto
at
org.apache.beam.runners.direct.DirectRunner$DirectPipelineResult.waitUntilFinish(DirectRunner.java:342)
at
org.apache.beam.runners.direct.DirectRunner$DirectPipelineResult.waitUntilFinish(DirectRunner.java:312)
at org.apache.beam.runners.direct.DirectRunner.run(DirectRunner.java:206)
at org.apache.beam.runners.direct.DirectRunner.run(DirectRunner.java:62)
at org.apache.beam.sdk.Pipeline.run(Pipeline.java:311)
at org.apache.beam.sdk.Pipeline.run(Pipeline.java:297)
at
ca.cbc.recsysdataflow.test.transforms.streaming.GetPredictionsCacheTest.testCache(GetPredictionsCacheTest.java:156)
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)
at
org.junit.runners.model.FrameworkMethod$1.runReflectiveCall(FrameworkMethod.java:50)
at
org.junit.internal.runners.model.ReflectiveCallable.run(ReflectiveCallable.java:12)
at
org.junit.runners.model.FrameworkMethod.invokeExplosively(FrameworkMethod.java:47)
at
org.junit.internal.runners.statements.InvokeMethod.evaluate(InvokeMethod.java:17)
at org.junit.runners.ParentRunner.runLeaf(ParentRunner.java:325)
at
org.junit.runners.BlockJUnit4ClassRunner.runChild(BlockJUnit4ClassRunner.java:78)
at
org.junit.runners.BlockJUnit4ClassRunner.runChild(BlockJUnit4ClassRunner.java:57)
at org.junit.runners.ParentRunner$3.run(ParentRunner.java:290)
at org.junit.runners.ParentRunner$1.schedule(ParentRunner.java:71)
at org.junit.runners.ParentRunner.runChildren(ParentRunner.java:288)
at org.junit.runners.ParentRunner.access$000(ParentRunner.java:58)
at org.junit.runners.ParentRunner$2.evaluate(ParentRunner.java:268)
at org.junit.internal.runners.statements.RunBefores.evaluate(RunBefores.java:26)
at org.junit.runners.ParentRunner.run(ParentRunner.java:363)
at
org.eclipse.jdt.internal.junit4.runner.JUnit4TestReference.run(JUnit4TestReference.java:86)
at
org.eclipse.jdt.internal.junit.runner.TestExecution.run(TestExecution.java:38)
at
org.eclipse.jdt.internal.junit.runner.RemoteTestRunner.runTests(RemoteTestRunner.java:538)
at
org.eclipse.jdt.internal.junit.runner.RemoteTestRunner.runTests(RemoteTestRunner.java:760)
at
org.eclipse.jdt.internal.junit.runner.RemoteTestRunner.run(RemoteTestRunner.java:460)
at
org.eclipse.jdt.internal.junit.runner.RemoteTestRunner.main(RemoteTestRunner.java:206)
Caused by: java.lang.NullPointerException: in
ca.cbc.recsysdataflow.PredictionResponseDto in array in
ca.cbc.recsysdataflow.PredictionResponseDto$.Prediction in array null of array
in field key of ca.cbc.recsysdataflow.PredictionResponseDto$.Prediction of
array in field predictions of ca.cbc.recsysdataflow.PredictionResponseDto
at org.apache.avro.reflect.ReflectDatumWriter.write(ReflectDatumWriter.java:161)
at org.apache.avro.generic.GenericDatumWriter.write(GenericDatumWriter.java:62)
at org.apache.beam.sdk.coders.AvroCoder.encode(AvroCoder.java:308)
at org.apache.beam.sdk.coders.Coder.encode(Coder.java:143)
at org.apache.beam.sdk.util.CoderUtils.encodeToSafeStream(CoderUtils.java:85)
at org.apache.beam.sdk.util.CoderUtils.encodeToByteArray(CoderUtils.java:69)
at org.apache.beam.sdk.util.CoderUtils.encodeToByteArray(CoderUtils.java:54)
at org.apache.beam.sdk.util.CoderUtils.clone(CoderUtils.java:148)
at
org.apache.beam.runners.direct.repackaged.runners.core.InMemoryStateInternals.uncheckedClone(InMemoryStateInternals.java:648)
at
org.apache.beam.runners.direct.repackaged.runners.core.InMemoryStateInternals.access$000(InMemoryStateInternals.java:62)
at
org.apache.beam.runners.direct.repackaged.runners.core.InMemoryStateInternals$InMemoryValue.copy(InMemoryStateInternals.java:221)
at
org.apache.beam.runners.direct.repackaged.runners.core.InMemoryStateInternals$InMemoryValue.copy(InMemoryStateInternals.java:181)
at
org.apache.beam.runners.direct.CopyOnAccessInMemoryStateInternals$CopyOnAccessInMemoryStateTable$CopyOnBindBinderFactory$1.bindValue(CopyOnAccessInMemoryStateInternals.java:301)
at
org.apache.beam.runners.direct.repackaged.runners.core.StateTags$2.bindValue(StateTags.java:71)
at org.apache.beam.sdk.state.StateSpecs$ValueStateSpec.bind(StateSpecs.java:278)
at org.apache.beam.sdk.state.StateSpecs$ValueStateSpec.bind(StateSpecs.java:267)
at
org.apache.beam.runners.direct.repackaged.runners.core.StateTags$SimpleStateTag.bind(StateTags.java:324)
at
org.apache.beam.runners.direct.repackaged.runners.core.StateTable.get(StateTable.java:60)
at
org.apache.beam.runners.direct.CopyOnAccessInMemoryStateInternals.state(CopyOnAccessInMemoryStateInternals.java:127)
at
org.apache.beam.runners.direct.CopyOnAccessInMemoryStateInternals.state(CopyOnAccessInMemoryStateInternals.java:121)
at
org.apache.beam.runners.direct.repackaged.runners.core.SimpleDoFnRunner$DoFnProcessContext.state(SimpleDoFnRunner.java:518)
at
ca.cbc.recsysdataflow.transforms.streaming.GetPredictionsFn$DoFnInvoker.invokeProcessElement(Unknown
Source)
Caused by: java.lang.NullPointerException
at
org.apache.avro.reflect.ReflectDatumWriter.writeArray(ReflectDatumWriter.java:71)
at
org.apache.avro.generic.GenericDatumWriter.writeWithoutConversion(GenericDatumWriter.java:120)
at org.apache.avro.generic.GenericDatumWriter.write(GenericDatumWriter.java:75)
at org.apache.avro.reflect.ReflectDatumWriter.write(ReflectDatumWriter.java:159)
at
org.apache.avro.generic.GenericDatumWriter.writeField(GenericDatumWriter.java:166)
at
org.apache.avro.specific.SpecificDatumWriter.writeField(SpecificDatumWriter.java:90)
at
org.apache.avro.reflect.ReflectDatumWriter.writeField(ReflectDatumWriter.java:191)
at
org.apache.avro.generic.GenericDatumWriter.writeRecord(GenericDatumWriter.java:156)
at
org.apache.avro.generic.GenericDatumWriter.writeWithoutConversion(GenericDatumWriter.java:118)
at org.apache.avro.generic.GenericDatumWriter.write(GenericDatumWriter.java:75)
at org.apache.avro.reflect.ReflectDatumWriter.write(ReflectDatumWriter.java:159)
at
org.apache.avro.generic.GenericDatumWriter.writeArray(GenericDatumWriter.java:192)
at
org.apache.avro.reflect.ReflectDatumWriter.writeArray(ReflectDatumWriter.java:68)
at
org.apache.avro.generic.GenericDatumWriter.writeWithoutConversion(GenericDatumWriter.java:120)
at org.apache.avro.generic.GenericDatumWriter.write(GenericDatumWriter.java:75)
at org.apache.avro.reflect.ReflectDatumWriter.write(ReflectDatumWriter.java:159)
at
org.apache.avro.generic.GenericDatumWriter.writeField(GenericDatumWriter.java:166)
at
org.apache.avro.specific.SpecificDatumWriter.writeField(SpecificDatumWriter.java:90)
at
org.apache.avro.reflect.ReflectDatumWriter.writeField(ReflectDatumWriter.java:191)
at
org.apache.avro.generic.GenericDatumWriter.writeRecord(GenericDatumWriter.java:156)
at
org.apache.avro.generic.GenericDatumWriter.writeWithoutConversion(GenericDatumWriter.java:118)
at org.apache.avro.generic.GenericDatumWriter.write(GenericDatumWriter.java:75)
at org.apache.avro.reflect.ReflectDatumWriter.write(ReflectDatumWriter.java:159)
at org.apache.avro.generic.GenericDatumWriter.write(GenericDatumWriter.java:62)
at org.apache.beam.sdk.coders.AvroCoder.encode(AvroCoder.java:308)
at org.apache.beam.sdk.coders.Coder.encode(Coder.java:143)
at org.apache.beam.sdk.util.CoderUtils.encodeToSafeStream(CoderUtils.java:85)
at org.apache.beam.sdk.util.CoderUtils.encodeToByteArray(CoderUtils.java:69)
at org.apache.beam.sdk.util.CoderUtils.encodeToByteArray(CoderUtils.java:54)
at org.apache.beam.sdk.util.CoderUtils.clone(CoderUtils.java:148)
at
org.apache.beam.runners.direct.repackaged.runners.core.InMemoryStateInternals.uncheckedClone(InMemoryStateInternals.java:648)
at
org.apache.beam.runners.direct.repackaged.runners.core.InMemoryStateInternals.access$000(InMemoryStateInternals.java:62)
at
org.apache.beam.runners.direct.repackaged.runners.core.InMemoryStateInternals$InMemoryValue.copy(InMemoryStateInternals.java:221)
at
org.apache.beam.runners.direct.repackaged.runners.core.InMemoryStateInternals$InMemoryValue.copy(InMemoryStateInternals.java:181)
at
org.apache.beam.runners.direct.CopyOnAccessInMemoryStateInternals$CopyOnAccessInMemoryStateTable$CopyOnBindBinderFactory$1.bindValue(CopyOnAccessInMemoryStateInternals.java:301)
at
org.apache.beam.runners.direct.repackaged.runners.core.StateTags$2.bindValue(StateTags.java:71)
at org.apache.beam.sdk.state.StateSpecs$ValueStateSpec.bind(StateSpecs.java:278)
at org.apache.beam.sdk.state.StateSpecs$ValueStateSpec.bind(StateSpecs.java:267)
at
org.apache.beam.runners.direct.repackaged.runners.core.StateTags$SimpleStateTag.bind(StateTags.java:324)
at
org.apache.beam.runners.direct.repackaged.runners.core.StateTable.get(StateTable.java:60)
at
org.apache.beam.runners.direct.CopyOnAccessInMemoryStateInternals.state(CopyOnAccessInMemoryStateInternals.java:127)
at
org.apache.beam.runners.direct.CopyOnAccessInMemoryStateInternals.state(CopyOnAccessInMemoryStateInternals.java:121)
at
org.apache.beam.runners.direct.repackaged.runners.core.SimpleDoFnRunner$DoFnProcessContext.state(SimpleDoFnRunner.java:518)
at
ca.cbc.recsysdataflow.transforms.streaming.GetPredictionsFn$DoFnInvoker.invokeProcessElement(Unknown
Source)
at
org.apache.beam.runners.direct.repackaged.runners.core.SimpleDoFnRunner.invokeProcessElement(SimpleDoFnRunner.java:177)
at
org.apache.beam.runners.direct.repackaged.runners.core.SimpleDoFnRunner.processElement(SimpleDoFnRunner.java:138)
at
org.apache.beam.runners.direct.repackaged.runners.core.SimplePushbackSideInputDoFnRunner.processElementInReadyWindows(SimplePushbackSideInputDoFnRunner.java:72)
at
org.apache.beam.runners.direct.ParDoEvaluator.processElement(ParDoEvaluator.java:179)
at
org.apache.beam.runners.direct.DoFnLifecycleManagerRemovingTransformEvaluator.processElement(DoFnLifecycleManagerRemovingTransformEvaluator.java:51)
at
org.apache.beam.runners.direct.StatefulParDoEvaluatorFactory$StatefulParDoEvaluator.processElement(StatefulParDoEvaluatorFactory.java:245)
at
org.apache.beam.runners.direct.DirectTransformExecutor.processElements(DirectTransformExecutor.java:161)
at
org.apache.beam.runners.direct.DirectTransformExecutor.run(DirectTransformExecutor.java:125)
at java.util.concurrent.Executors$RunnableAdapter.call(Executors.java:511)
at java.util.concurrent.FutureTask.run(FutureTask.java:266)
at
java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1149)
at
java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:624)
at java.lang.Thread.run(Thread.java:748)
{code}
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