[FLINK-2658] fieldsGrouping for multiple output streams fails

• Type: Bug
• Status: Closed
• Priority: Major
• Resolution: Fixed
• Component/s: Legacy Components / Storm Compatibility
• Assignee: Matthias J. Sax
• Reporter: Matthias J. Sax
• Created: 11/Sep/15 11:01
• Updated: 14/Sep/15 16:02
• Resolved: 14/Sep/15 16:02

Description

If a Spout or Bolt declares multiple output streams and another Bolt connects to one of those streams via "fieldsGrouping", the call to FlinkTopologyBuilder.createTopology() fails with the following exception:

org.apache.flink.api.common.InvalidProgramException: Specifying keys via field positions is only valid for tuple data types. Type: PojoType<org.apache.flink.stormcompatibility.util.SplitStreamType, fields = [streamId: String, value: GenericType<java.lang.Object>]>
	at org.apache.flink.api.java.operators.Keys$ExpressionKeys.<init>(Keys.java:209)
	at org.apache.flink.api.java.operators.Keys$ExpressionKeys.<init>(Keys.java:203)
	at org.apache.flink.streaming.api.datastream.DataStream.groupBy(DataStream.java:285)
	at org.apache.flink.stormcompatibility.api.FlinkTopologyBuilder.createTopology(FlinkTopologyBuilder.java:200)
	at org.apache.flink.stormcompatibility.api.FlinkTopologyBuilderTest.testFieldsGroupingOnMultipleBoltOutputStreams(FlinkTopologyBuilderTest.java:73)
	at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
	at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:57)
	at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43)
	at java.lang.reflect.Method.invoke(Method.java:606)
	at org.junit.runners.model.FrameworkMethod$1.runReflectiveCall(FrameworkMethod.java:47)
	at org.junit.internal.runners.model.ReflectiveCallable.run(ReflectiveCallable.java:12)
	at org.junit.runners.model.FrameworkMethod.invokeExplosively(FrameworkMethod.java:44)
	at org.junit.internal.runners.statements.InvokeMethod.evaluate(InvokeMethod.java:17)
	at org.junit.runners.ParentRunner.runLeaf(ParentRunner.java:271)
	at org.junit.runners.BlockJUnit4ClassRunner.runChild(BlockJUnit4ClassRunner.java:70)
	at org.junit.runners.BlockJUnit4ClassRunner.runChild(BlockJUnit4ClassRunner.java:50)
	at org.junit.runners.ParentRunner$3.run(ParentRunner.java:238)
	at org.junit.runners.ParentRunner$1.schedule(ParentRunner.java:63)
	at org.junit.runners.ParentRunner.runChildren(ParentRunner.java:236)
	at org.junit.runners.ParentRunner.access$000(ParentRunner.java:53)
	at org.junit.runners.ParentRunner$2.evaluate(ParentRunner.java:229)
	at org.junit.runners.ParentRunner.run(ParentRunner.java:309)
	at org.eclipse.jdt.internal.junit4.runner.JUnit4TestReference.run(JUnit4TestReference.java:50)
	at org.eclipse.jdt.internal.junit.runner.TestExecution.run(TestExecution.java:38)
	at org.eclipse.jdt.internal.junit.runner.RemoteTestRunner.runTests(RemoteTestRunner.java:467)
	at org.eclipse.jdt.internal.junit.runner.RemoteTestRunner.runTests(RemoteTestRunner.java:683)
	at org.eclipse.jdt.internal.junit.runner.RemoteTestRunner.run(RemoteTestRunner.java:390)
	at org.eclipse.jdt.internal.junit.runner.RemoteTestRunner.main(RemoteTestRunner.java:197)

Fix: either introduce a mapper, that "flattens" the SplitStreamType in to regular tuple type that is nested inside or provide a custom KeySelector.