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Posted to commits@beam.apache.org by "Maximilian Michels (JIRA)" <ji...@apache.org> on 2016/05/17 15:30:13 UTC
[jira] [Closed] (BEAM-291) PDone type translation fails
[ https://issues.apache.org/jira/browse/BEAM-291?page=com.atlassian.jira.plugin.system.issuetabpanels:all-tabpanel ]
Maximilian Michels closed BEAM-291.
-----------------------------------
Resolution: Not A Problem
I was using this example:
{noformat}
final Pipeline p = Pipeline.create(options);
p.apply(Create.of("test"))
.apply(ParDo.of(new DoFn<String, PDone>() {
@Override
public void processElement(ProcessContext c) throws Exception {
System.out.println("element: " + c.element());
}
}));
p.run();
{noformat}
You're right, PDone shouldn't apparently be used in places besides PTransform. Looking at the existing sinks, the best way to avoid a return type is to use the {{Void}} type as the return type for a DoFn. So this becomes
{noformat}
...
.apply(ParDo.of(new DoFn<String, Void>() {
...
{noformat}
and works as expected :)
> PDone type translation fails
> ----------------------------
>
> Key: BEAM-291
> URL: https://issues.apache.org/jira/browse/BEAM-291
> Project: Beam
> Issue Type: Bug
> Components: runner-flink
> Reporter: Maximilian Michels
> Assignee: Maximilian Michels
>
> The {{PDone}} output type is currently not supported by the Flink Runner because it doesn't have a Coder associated. This could also get in the way when translating native Beam sinks which would likely return PDone.
> The simplest solution is to create a dummy PDone coder. Alternatively, we could check for the PDone return type during translation and not retrieve the coder at all.
> {noformat}
> Exception in thread "main" java.lang.IllegalStateException: Unable to return a default Coder for AnonymousParDo.out [PCollection]. Correct one of the following root causes:
> No Coder has been manually specified; you may do so using .setCoder().
> Inferring a Coder from the CoderRegistry failed: Unable to provide a default Coder for org.apache.beam.sdk.values.PDone. Correct one of the following root causes:
> Building a Coder using a registered CoderFactory failed: Cannot provide coder based on value with class org.apache.beam.sdk.values.PDone: No CoderFactory has been registered for the class.
> Building a Coder from the @DefaultCoder annotation failed: Class org.apache.beam.sdk.values.PDone does not have a @DefaultCoder annotation.
> Building a Coder from the fallback CoderProvider failed: Cannot provide coder for type org.apache.beam.sdk.values.PDone: org.apache.beam.sdk.coders.protobuf.ProtoCoder$1@72ef8d15 could not provide a Coder for type org.apache.beam.sdk.values.PDone: Cannot provide ProtoCoder because org.apache.beam.sdk.values.PDone is not a subclass of com.google.protobuf.Message; org.apache.beam.sdk.coders.SerializableCoder$1@6aa8e115 could not provide a Coder for type org.apache.beam.sdk.values.PDone: Cannot provide SerializableCoder because org.apache.beam.sdk.values.PDone does not implement Serializable.
> Using the default output Coder from the producing PTransform failed: Unable to provide a default Coder for org.apache.beam.sdk.values.PDone. Correct one of the following root causes:
> Building a Coder using a registered CoderFactory failed: Cannot provide coder based on value with class org.apache.beam.sdk.values.PDone: No CoderFactory has been registered for the class.
> Building a Coder from the @DefaultCoder annotation failed: Class org.apache.beam.sdk.values.PDone does not have a @DefaultCoder annotation.
> Building a Coder from the fallback CoderProvider failed: Cannot provide coder for type org.apache.beam.sdk.values.PDone: org.apache.beam.sdk.coders.protobuf.ProtoCoder$1@72ef8d15 could not provide a Coder for type org.apache.beam.sdk.values.PDone: Cannot provide ProtoCoder because org.apache.beam.sdk.values.PDone is not a subclass of com.google.protobuf.Message; org.apache.beam.sdk.coders.SerializableCoder$1@6aa8e115 could not provide a Coder for type org.apache.beam.sdk.values.PDone: Cannot provide SerializableCoder because org.apache.beam.sdk.values.PDone does not implement Serializable.
> at org.apache.beam.sdk.values.TypedPValue.inferCoderOrFail(TypedPValue.java:196)
> at org.apache.beam.sdk.values.TypedPValue.getCoder(TypedPValue.java:49)
> at org.apache.beam.sdk.values.PCollection.getCoder(PCollection.java:138)
> at org.apache.beam.runners.flink.translation.FlinkStreamingTransformTranslators$ParDoBoundStreamingTranslator.translateNode(FlinkStreamingTransformTranslators.java:315)
> at org.apache.beam.runners.flink.translation.FlinkStreamingTransformTranslators$ParDoBoundStreamingTranslator.translateNode(FlinkStreamingTransformTranslators.java:305)
> at org.apache.beam.runners.flink.translation.FlinkStreamingPipelineTranslator.applyStreamingTransform(FlinkStreamingPipelineTranslator.java:108)
> at org.apache.beam.runners.flink.translation.FlinkStreamingPipelineTranslator.visitPrimitiveTransform(FlinkStreamingPipelineTranslator.java:89)
> at org.apache.beam.sdk.runners.TransformTreeNode.visit(TransformTreeNode.java:225)
> at org.apache.beam.sdk.runners.TransformTreeNode.visit(TransformTreeNode.java:220)
> at org.apache.beam.sdk.runners.TransformHierarchy.visit(TransformHierarchy.java:104)
> at org.apache.beam.sdk.Pipeline.traverseTopologically(Pipeline.java:292)
> at org.apache.beam.runners.flink.translation.FlinkPipelineTranslator.translate(FlinkPipelineTranslator.java:34)
> at org.apache.beam.runners.flink.FlinkPipelineExecutionEnvironment.translate(FlinkPipelineExecutionEnvironment.java:132)
> at org.apache.beam.runners.flink.FlinkPipelineRunner.run(FlinkPipelineRunner.java:108)
> at org.apache.beam.runners.flink.FlinkPipelineRunner.run(FlinkPipelineRunner.java:49)
> at org.apache.beam.sdk.Pipeline.run(Pipeline.java:182)
> at org.apache.beam.runners.flink.examples.streaming.KafkaBeamExample.main(KafkaBeamExample.java:57)
> 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:497)
> at com.intellij.rt.execution.application.AppMain.main(AppMain.java:144)
> {noformat}
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