zentol commented on code in PR #20757: URL: https://github.com/apache/flink/pull/20757#discussion_r989925818
########## flink-core/src/test/java/org/apache/flink/api/connector/source/lib/DataGeneratorSourceTest.java: ########## @@ -0,0 +1,250 @@ +/* + * Licensed to the Apache Software Foundation (ASF) under one + * or more contributor license agreements. See the NOTICE file + * distributed with this work for additional information + * regarding copyright ownership. The ASF licenses this file + * to you under the Apache License, Version 2.0 (the + * "License"); you may not use this file except in compliance + * with the License. You may obtain a copy of the License at + * + * http://www.apache.org/licenses/LICENSE-2.0 + * + * Unless required by applicable law or agreed to in writing, software + * distributed under the License is distributed on an "AS IS" BASIS, + * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. + * See the License for the specific language governing permissions and + * limitations under the License. + */ + +package org.apache.flink.api.connector.source.lib; + +import org.apache.flink.api.common.eventtime.Watermark; +import org.apache.flink.api.common.typeinfo.Types; +import org.apache.flink.api.connector.source.ReaderOutput; +import org.apache.flink.api.connector.source.SourceEvent; +import org.apache.flink.api.connector.source.SourceOutput; +import org.apache.flink.api.connector.source.SourceReader; +import org.apache.flink.api.connector.source.SourceReaderContext; +import org.apache.flink.api.connector.source.SplitEnumerator; +import org.apache.flink.api.connector.source.datagen.DataGeneratorSource; +import org.apache.flink.api.connector.source.datagen.GeneratorFunction; +import org.apache.flink.api.connector.source.mocks.MockSplitEnumeratorContext; +import org.apache.flink.configuration.Configuration; +import org.apache.flink.core.io.InputStatus; +import org.apache.flink.metrics.groups.SourceReaderMetricGroup; +import org.apache.flink.metrics.groups.UnregisteredMetricsGroup; +import org.apache.flink.mock.Whitebox; +import org.apache.flink.util.SimpleUserCodeClassLoader; +import org.apache.flink.util.UserCodeClassLoader; + +import org.junit.jupiter.api.Assertions; +import org.junit.jupiter.api.DisplayName; +import org.junit.jupiter.api.Test; + +import java.util.ArrayList; +import java.util.Arrays; +import java.util.Collection; +import java.util.List; +import java.util.Queue; + +import static org.assertj.core.api.Assertions.assertThat; + +/** Tests for the {@link DataGeneratorSource}. */ +public class DataGeneratorSourceTest { + + @Test + @DisplayName("Correctly restores SplitEnumerator from a snapshot.") + public void testRestoreEnumerator() throws Exception { + final GeneratorFunction<Long, Long> generatorFunctionStateless = index -> index; + final DataGeneratorSource<Long> dataGeneratorSource = + new DataGeneratorSource<>(generatorFunctionStateless, 100, Types.LONG); + + final int parallelism = 2; + final MockSplitEnumeratorContext<NumberSequenceSource.NumberSequenceSplit> context = + new MockSplitEnumeratorContext<>(parallelism); + + SplitEnumerator< + NumberSequenceSource.NumberSequenceSplit, + Collection<NumberSequenceSource.NumberSequenceSplit>> + enumerator = dataGeneratorSource.createEnumerator(context); + + // start() is not strictly necessary in the current implementation, but should logically be + // executed in this order (protect against any breaking changes in the start() method). + enumerator.start(); + + Collection<NumberSequenceSource.NumberSequenceSplit> enumeratorState = + enumerator.snapshotState(0); + + @SuppressWarnings("unchecked") + final Queue<NumberSequenceSource.NumberSequenceSplit> splits = + (Queue<NumberSequenceSource.NumberSequenceSplit>) + Whitebox.getInternalState(enumerator, "remainingSplits"); + + assertThat(splits).hasSize(parallelism); + + enumerator = dataGeneratorSource.restoreEnumerator(context, enumeratorState); + + @SuppressWarnings("unchecked") + final Queue<NumberSequenceSource.NumberSequenceSplit> restoredSplits = + (Queue<NumberSequenceSource.NumberSequenceSplit>) + Whitebox.getInternalState(enumerator, "remainingSplits"); + + assertThat(restoredSplits).hasSize(enumeratorState.size()); + } + + @Test + @DisplayName("Uses the underlying NumberSequenceSource correctly for checkpointing.") + public void testReaderCheckpoints() throws Exception { + final long from = 177; + final long mid = 333; + final long to = 563; + final long elementsPerCycle = (to - from) / 3; + + final TestingReaderOutput<Long> out = new TestingReaderOutput<>(); + + SourceReader<Long, NumberSequenceSource.NumberSequenceSplit> reader = createReader(); + reader.addSplits( + Arrays.asList( + new NumberSequenceSource.NumberSequenceSplit("split-1", from, mid), + new NumberSequenceSource.NumberSequenceSplit("split-2", mid + 1, to))); + + long remainingInCycle = elementsPerCycle; + while (reader.pollNext(out) != InputStatus.END_OF_INPUT) { + if (--remainingInCycle <= 0) { + remainingInCycle = elementsPerCycle; + // checkpoint + List<NumberSequenceSource.NumberSequenceSplit> splits = reader.snapshotState(1L); + + // re-create and restore + reader = createReader(); + if (splits.isEmpty()) { + reader.notifyNoMoreSplits(); + } else { + reader.addSplits(splits); + } + } + } + + final List<Long> result = out.getEmittedRecords(); + validateSequence(result, from, to); + } + + private static void validateSequence( + final List<Long> sequence, final long from, final long to) { + if (sequence.size() != to - from + 1) { + failSequence(sequence, from, to); + } + + long nextExpected = from; + for (Long next : sequence) { + if (next != nextExpected++) { + failSequence(sequence, from, to); + } + } + } + + private static void failSequence(final List<Long> sequence, final long from, final long to) { + Assertions.fail( + String.format( + "Expected: A sequence [%d, %d], but found: sequence (size %d) : %s", + from, to, sequence.size(), sequence)); + } + + private static SourceReader<Long, NumberSequenceSource.NumberSequenceSplit> createReader() + throws Exception { + // the arguments passed in the source constructor matter only to the enumerator + GeneratorFunction<Long, Long> generatorFunctionStateless = index -> index; + DataGeneratorSource<Long> dataGeneratorSource = + new DataGeneratorSource<>(generatorFunctionStateless, Long.MAX_VALUE, Types.LONG); + + return dataGeneratorSource.createReader(new DummyReaderContext()); + } + + // ------------------------------------------------------------------------ + // test utils / mocks + // + // the "flink-connector-test-utils module has proper mocks and utils, + // but cannot be used here, because it would create a cyclic dependency. + // ------------------------------------------------------------------------ + + private static final class DummyReaderContext implements SourceReaderContext { + + @Override + public SourceReaderMetricGroup metricGroup() { + return UnregisteredMetricsGroup.createSourceReaderMetricGroup(); + } + + @Override + public Configuration getConfiguration() { + return new Configuration(); + } + + @Override + public String getLocalHostName() { + return "localhost"; + } + + @Override + public int getIndexOfSubtask() { + return 0; + } + + @Override + public void sendSplitRequest() {} + + @Override + public void sendSourceEventToCoordinator(SourceEvent sourceEvent) {} + + @Override + public UserCodeClassLoader getUserCodeClassLoader() { + return SimpleUserCodeClassLoader.create(getClass().getClassLoader()); + } + + @Override + public int currentParallelism() { + return 1; + } + } + + private static final class TestingReaderOutput<E> implements ReaderOutput<E> { Review Comment: I'm tempted to keep it in flink-core because that's where the Source interface is, and I feel like outside of the source the rate limiter would be difficult/weird to use due to it's async nature. -- This is an automated message from the Apache Git Service. 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