如何使用Apache Beam DSL API？

Question

I am trying to implement the DSL API example from the Apache Beam documentation . I am using the newest versions of the apache beam libraries (2.4.0)

The code I am running is the same as in the docs:

@Rule
public final transient TestPipeline p = TestPipeline.create();

@Test
public void dslTest() {
    RowType appType = RowSqlType
            .builder()
            .withIntegerField("appId")
            .withVarcharField("description")
            .withTimestampField("rowtime")
            .build();

    // Create a concrete row with that type.
    Row row = Row.withRowType(appType)
            .addValues(1, "Some cool app", new Date())
            .build();

    // Create a source PCollection containing only that row
    PCollection<Row> testApps = PBegin
            .in(p)
            .apply(Create
                    .of(row)
                    .withCoder(appType.getRowCoder()));

    PCollection<Row> filteredNames = testApps.apply(
            BeamSql.query(
                    "SELECT appId, description, rowtime "
                            + "FROM PCOLLECTION "
                            + "WHERE appId=1"));
}

This always fails with the following error:

java.lang.AssertionError
at org.apache.beam.sdks.java.extensions.sql.repackaged.org.apache.calcite.plan.volcano.VolcanoPlanner.changeTraits(VolcanoPlanner.java:546)
at org.apache.beam.sdks.java.extensions.sql.repackaged.org.apache.calcite.tools.Programs$RuleSetProgram.run(Programs.java:365)
at org.apache.beam.sdks.java.extensions.sql.repackaged.org.apache.calcite.prepare.PlannerImpl.transform(PlannerImpl.java:336)
at org.apache.beam.sdk.extensions.sql.impl.planner.BeamQueryPlanner.convertToBeamRel(BeamQueryPlanner.java:165)
at org.apache.beam.sdk.extensions.sql.impl.planner.BeamQueryPlanner.validateAndConvert(BeamQueryPlanner.java:156)
at org.apache.beam.sdk.extensions.sql.impl.planner.BeamQueryPlanner.convertToBeamRel(BeamQueryPlanner.java:144)
at org.apache.beam.sdk.extensions.sql.QueryTransform.expand(QueryTransform.java:73)
at org.apache.beam.sdk.extensions.sql.QueryTransform.expand(QueryTransform.java:47)
at org.apache.beam.sdk.Pipeline.applyInternal(Pipeline.java:537)
at org.apache.beam.sdk.Pipeline.applyTransform(Pipeline.java:472)
at org.apache.beam.sdk.values.PCollection.apply(PCollection.java:286)
at PipelineTest.dslTest(PipelineTest.java:42)
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:324)
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$2.evaluate(ParentRunner.java:268)
at org.junit.runners.ParentRunner.run(ParentRunner.java:363)
at org.junit.runner.JUnitCore.run(JUnitCore.java:137)
at com.intellij.junit4.JUnit4IdeaTestRunner.startRunnerWithArgs(JUnit4IdeaTestRunner.java:68)
at com.intellij.rt.execution.junit.IdeaTestRunner$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)

What is the correct way to run this test, or is this a bug and the dsl apis are not working?

Answer 1

It looks like a known issue, there's an assertion inside a planner which Beam fails to satisfy, see this jira . The fix for it is not ready at the moment.

Current workaround is to disable assertions, depending on your build system:

• if you're using gradle, then in build.gradle you will have something like this:

  \ntest { \n    jvmArgs "-da" \n} \n

• if you're using maven, then in pom.xml you will have something like this:

  \n\n <plugin> \n    <groupId>org.apache.maven.plugins</groupId> \n    <artifactId>maven-surefire-plugin</artifactId> \n    <configuration> \n      <argLine>-da</argLine> \n\n