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https://issues.apache.org/jira/browse/BEAM-2993?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=16185511#comment-16185511
]
Etienne Chauchot commented on BEAM-2993:
----------------------------------------
Well, I have a use case but it is not a very common case :) The collections use
a lazy avro coder whose responsibility is to determine the schema when the
pipeline runs and then delegate to the {{AvroCoder}}. So what it lacks is a
write method signature with no schema parameter. That is why I planned to use
{{AvroIO.writeCustomTypeToGenericRecords()}}. Please take a look at that code
https://github.com/echauchot/beam/blob/69928dd59cdaf259e39f047735bd33a600673999/sdks/java/core/src/test/java/org/apache/beam/sdk/io/AvroIOTransformTest.java#L393.
It just does a test of {{AvroIO.writeCustomTypeToGenericRecords()}} with a
side input which contains the schema extracted with a {{ParDo}}. Besides this
code is not finished yet because it suffers from a serialization pb in the
write with sharding
{code}
java.lang.IllegalArgumentException: unable to serialize
org.apache.beam.sdk.io.WriteFiles$ApplyShardingKey@7a3793c7
at
org.apache.beam.sdk.util.SerializableUtils.serializeToByteArray(SerializableUtils.java:53)
at
org.apache.beam.sdk.util.SerializableUtils.clone(SerializableUtils.java:90)
at
org.apache.beam.sdk.transforms.ParDo$SingleOutput.<init>(ParDo.java:592)
at org.apache.beam.sdk.transforms.ParDo.of(ParDo.java:435)
at org.apache.beam.sdk.io.WriteFiles.createWrite(WriteFiles.java:730)
at org.apache.beam.sdk.io.WriteFiles.expand(WriteFiles.java:194)
at org.apache.beam.sdk.io.WriteFiles.expand(WriteFiles.java:109)
at org.apache.beam.sdk.Pipeline.applyInternal(Pipeline.java:525)
at org.apache.beam.sdk.Pipeline.applyTransform(Pipeline.java:479)
at org.apache.beam.sdk.values.PCollection.apply(PCollection.java:297)
at org.apache.beam.sdk.io.AvroIO$TypedWrite.expand(AvroIO.java:1177)
at org.apache.beam.sdk.io.AvroIO$TypedWrite.expand(AvroIO.java:842)
at org.apache.beam.sdk.Pipeline.applyInternal(Pipeline.java:525)
at org.apache.beam.sdk.Pipeline.applyTransform(Pipeline.java:460)
at org.apache.beam.sdk.values.PCollection.apply(PCollection.java:284)
at
org.apache.beam.sdk.io.AvroIOTransformTest$AvroIOWriteTransformTest.testWriteGenericRecords(AvroIOTransformTest.java:417)
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.apache.beam.sdk.testing.TestPipeline$1.evaluate(TestPipeline.java:327)
at org.junit.rules.ExternalResource$1.evaluate(ExternalResource.java:48)
at org.junit.rules.RunRules.evaluate(RunRules.java:20)
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.runners.ParentRunner.run(ParentRunner.java:363)
at org.junit.runners.Suite.runChild(Suite.java:128)
at org.junit.runners.Suite.runChild(Suite.java:27)
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$2.evaluate(ParentRunner.java:268)
at org.junit.runners.ParentRunner.run(ParentRunner.java:363)
at org.junit.runner.JUnitCore.run(JUnitCore.java:137)
at
com.intellij.junit4.JUnit4IdeaTestRunner.startRunnerWithArgs(JUnit4IdeaTestRunner.java:68)
at
com.intellij.rt.execution.junit.IdeaTestRunner$Repeater.startRunnerWithArgs(IdeaTestRunner.java:47)
at
com.intellij.rt.execution.junit.JUnitStarter.prepareStreamsAndStart(JUnitStarter.java:242)
at
com.intellij.rt.execution.junit.JUnitStarter.main(JUnitStarter.java:70)
Caused by: java.io.NotSerializableException:
org.apache.beam.sdk.io.AvroIOTransformTest$AvroIOWriteTransformTest
at java.io.ObjectOutputStream.writeObject0(ObjectOutputStream.java:1184)
at
java.io.ObjectOutputStream.defaultWriteFields(ObjectOutputStream.java:1548)
at
java.io.ObjectOutputStream.writeSerialData(ObjectOutputStream.java:1509)
at
java.io.ObjectOutputStream.writeOrdinaryObject(ObjectOutputStream.java:1432)
at java.io.ObjectOutputStream.writeObject0(ObjectOutputStream.java:1178)
at
java.io.ObjectOutputStream.defaultWriteFields(ObjectOutputStream.java:1548)
at
java.io.ObjectOutputStream.writeSerialData(ObjectOutputStream.java:1509)
at
java.io.ObjectOutputStream.writeOrdinaryObject(ObjectOutputStream.java:1432)
at java.io.ObjectOutputStream.writeObject0(ObjectOutputStream.java:1178)
at
java.io.ObjectOutputStream.defaultWriteFields(ObjectOutputStream.java:1548)
at
java.io.ObjectOutputStream.writeSerialData(ObjectOutputStream.java:1509)
at
java.io.ObjectOutputStream.writeOrdinaryObject(ObjectOutputStream.java:1432)
at java.io.ObjectOutputStream.writeObject0(ObjectOutputStream.java:1178)
at
java.io.ObjectOutputStream.defaultWriteFields(ObjectOutputStream.java:1548)
at
java.io.ObjectOutputStream.writeSerialData(ObjectOutputStream.java:1509)
at
java.io.ObjectOutputStream.writeOrdinaryObject(ObjectOutputStream.java:1432)
at java.io.ObjectOutputStream.writeObject0(ObjectOutputStream.java:1178)
at java.io.ObjectOutputStream.writeObject(ObjectOutputStream.java:348)
at
org.apache.beam.sdk.util.SerializableUtils.serializeToByteArray(SerializableUtils.java:49)
... 48 more
{code}
> AvroIO.write without specifying a schema
> ----------------------------------------
>
> Key: BEAM-2993
> URL: https://issues.apache.org/jira/browse/BEAM-2993
> Project: Beam
> Issue Type: Improvement
> Components: sdk-java-extensions
> Reporter: Etienne Chauchot
> Assignee: Etienne Chauchot
>
> Similarly to https://issues.apache.org/jira/browse/BEAM-2677, we should be
> able to write to avro files using {{AvroIO}} without specifying a schema at
> build time. Consider the following use case: a user has a
> {{PCollection<GenericRecord>}} but the schema is only known while running
> the pipeline. {{AvroIO.writeGenericRecords}} needs the schema, but the
> schema is already available in {{GenericRecord}}. We should be able to call
> {{AvroIO.writeGenericRecords()}} with no schema.
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