FlinkKafkaConsumerBaseFrom11MigrationTest.java example

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/*
 * 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.streaming.connectors.kafka;

import org.apache.flink.streaming.api.TimeCharacteristic;
import org.apache.flink.streaming.api.functions.AssignerWithPeriodicWatermarks;
import org.apache.flink.streaming.api.functions.AssignerWithPunctuatedWatermarks;
import org.apache.flink.streaming.api.operators.StreamSource;
import org.apache.flink.streaming.api.operators.StreamingRuntimeContext;
import org.apache.flink.streaming.connectors.kafka.config.OffsetCommitMode;
import org.apache.flink.streaming.connectors.kafka.internals.AbstractFetcher;
import org.apache.flink.streaming.connectors.kafka.internals.KafkaTopicPartition;
import org.apache.flink.streaming.connectors.kafka.internals.KafkaTopicPartitionStateSentinel;
import org.apache.flink.streaming.util.AbstractStreamOperatorTestHarness;
import org.apache.flink.streaming.util.serialization.KeyedDeserializationSchema;
import org.apache.flink.util.SerializedValue;
import org.junit.Assert;
import org.junit.Test;

import java.net.URL;
import java.util.ArrayList;
import java.util.Arrays;
import java.util.Collections;
import java.util.Map;
import java.util.HashMap;
import java.util.List;

import static org.mockito.Mockito.mock;

/**
 * Tests for checking whether {@link FlinkKafkaConsumerBase} can restore from snapshots that were
 * done using the Flink 1.1 {@link FlinkKafkaConsumerBase}.
 *
 * <p>For regenerating the binary snapshot file you have to run the commented out portion
 * of each test on a checkout of the Flink 1.1 branch.
 */
public class FlinkKafkaConsumerBaseFrom11MigrationTest {

	/** Test restoring from an legacy empty state, when no partitions could be found for topics. */
	@Test
	public void testRestoreFromFlink11WithEmptyStateNoPartitions() throws Exception {
		final DummyFlinkKafkaConsumer<String> consumerFunction =
			new DummyFlinkKafkaConsumer<>(Collections.<KafkaTopicPartition>emptyList());

		StreamSource<String, DummyFlinkKafkaConsumer<String>> consumerOperator = new StreamSource<>(consumerFunction);

		final AbstractStreamOperatorTestHarness<String> testHarness =
			new AbstractStreamOperatorTestHarness<>(consumerOperator, 1, 1, 0);

		testHarness.setTimeCharacteristic(TimeCharacteristic.ProcessingTime);

		testHarness.setup();
		// restore state from binary snapshot file using legacy method
		testHarness.initializeStateFromLegacyCheckpoint(
			getResourceFilename("kafka-consumer-migration-test-flink1.1-empty-state-snapshot"));
		testHarness.open();

		// assert that no partitions were found and is empty
		Assert.assertTrue(consumerFunction.getSubscribedPartitionsToStartOffsets() != null);
		Assert.assertTrue(consumerFunction.getSubscribedPartitionsToStartOffsets().isEmpty());

		// assert that no state was restored
		Assert.assertTrue(consumerFunction.getRestoredState() == null);

		consumerOperator.close();
		consumerOperator.cancel();
	}

	/** Test restoring from an empty state taken using Flink 1.1, when some partitions could be found for topics. */
	@Test
	public void testRestoreFromFlink11WithEmptyStateWithPartitions() throws Exception {
		final List<KafkaTopicPartition> partitions = new ArrayList<>();
		partitions.add(new KafkaTopicPartition("abc", 13));
		partitions.add(new KafkaTopicPartition("def", 7));

		final DummyFlinkKafkaConsumer<String> consumerFunction = new DummyFlinkKafkaConsumer<>(partitions);

		StreamSource<String, DummyFlinkKafkaConsumer<String>> consumerOperator =
			new StreamSource<>(consumerFunction);

		final AbstractStreamOperatorTestHarness<String> testHarness =
			new AbstractStreamOperatorTestHarness<>(consumerOperator, 1, 1, 0);

		testHarness.setTimeCharacteristic(TimeCharacteristic.ProcessingTime);

		testHarness.setup();
		// restore state from binary snapshot file using legacy method
		testHarness.initializeStateFromLegacyCheckpoint(
			getResourceFilename("kafka-consumer-migration-test-flink1.1-empty-state-snapshot"));
		testHarness.open();

		// the expected state in "kafka-consumer-migration-test-flink1.1-empty-state-snapshot";
		// since the state is empty, the consumer should reflect on the startup mode to determine start offsets.
		final HashMap<KafkaTopicPartition, Long> expectedSubscribedPartitionsWithStartOffsets = new HashMap<>();
		expectedSubscribedPartitionsWithStartOffsets.put(new KafkaTopicPartition("abc", 13), KafkaTopicPartitionStateSentinel.GROUP_OFFSET);
		expectedSubscribedPartitionsWithStartOffsets.put(new KafkaTopicPartition("def", 7), KafkaTopicPartitionStateSentinel.GROUP_OFFSET);

		// assert that there are partitions and is identical to expected list
		Assert.assertTrue(consumerFunction.getSubscribedPartitionsToStartOffsets() != null);
		Assert.assertTrue(!consumerFunction.getSubscribedPartitionsToStartOffsets().isEmpty());
		Assert.assertEquals(expectedSubscribedPartitionsWithStartOffsets, consumerFunction.getSubscribedPartitionsToStartOffsets());

		// assert that no state was restored
		Assert.assertTrue(consumerFunction.getRestoredState() == null);

		consumerOperator.close();
		consumerOperator.cancel();
	}

	/** Test restoring from a non-empty state taken using Flink 1.1, when some partitions could be found for topics. */
	@Test
	public void testRestoreFromFlink11() throws Exception {
		final List<KafkaTopicPartition> partitions = new ArrayList<>();
		partitions.add(new KafkaTopicPartition("abc", 13));
		partitions.add(new KafkaTopicPartition("def", 7));

		final DummyFlinkKafkaConsumer<String> consumerFunction = new DummyFlinkKafkaConsumer<>(partitions);

		StreamSource<String, DummyFlinkKafkaConsumer<String>> consumerOperator =
			new StreamSource<>(consumerFunction);

		final AbstractStreamOperatorTestHarness<String> testHarness =
			new AbstractStreamOperatorTestHarness<>(consumerOperator, 1, 1, 0);

		testHarness.setTimeCharacteristic(TimeCharacteristic.ProcessingTime);

		testHarness.setup();
		// restore state from binary snapshot file using legacy method
		testHarness.initializeStateFromLegacyCheckpoint(
			getResourceFilename("kafka-consumer-migration-test-flink1.1-snapshot"));
		testHarness.open();

		// the expected state in "kafka-consumer-migration-test-flink1.1-snapshot"
		final HashMap<KafkaTopicPartition, Long> expectedState = new HashMap<>();
		expectedState.put(new KafkaTopicPartition("abc", 13), 16768L);
		expectedState.put(new KafkaTopicPartition("def", 7), 987654321L);

		// assert that there are partitions and is identical to expected list
		Assert.assertTrue(consumerFunction.getSubscribedPartitionsToStartOffsets() != null);
		Assert.assertTrue(!consumerFunction.getSubscribedPartitionsToStartOffsets().isEmpty());

		// on restore, subscribedPartitionsToStartOffsets should be identical to the restored state
		Assert.assertEquals(expectedState, consumerFunction.getSubscribedPartitionsToStartOffsets());

		// assert that state is correctly restored from legacy checkpoint
		Assert.assertTrue(consumerFunction.getRestoredState() != null);
		Assert.assertEquals(expectedState, consumerFunction.getRestoredState());

		consumerOperator.close();
		consumerOperator.cancel();
	}

	// ------------------------------------------------------------------------

	private static String getResourceFilename(String filename) {
		ClassLoader cl = FlinkKafkaConsumerBaseFrom11MigrationTest.class.getClassLoader();
		URL resource = cl.getResource(filename);
		if (resource == null) {
			throw new NullPointerException("Missing snapshot resource.");
		}
		return resource.getFile();
	}

	private static class DummyFlinkKafkaConsumer<T> extends FlinkKafkaConsumerBase<T> {
		private static final long serialVersionUID = 1L;

		private final List<KafkaTopicPartition> partitions;

		@SuppressWarnings("unchecked")
		DummyFlinkKafkaConsumer(List<KafkaTopicPartition> partitions) {
			super(Arrays.asList("dummy-topic"), (KeyedDeserializationSchema< T >) mock(KeyedDeserializationSchema.class));
			this.partitions = partitions;
		}

		@Override
		protected AbstractFetcher<T, ?> createFetcher(
				SourceContext<T> sourceContext,
				Map<KafkaTopicPartition, Long> thisSubtaskPartitionsWithStartOffsets,
				SerializedValue<AssignerWithPeriodicWatermarks<T>> watermarksPeriodic,
				SerializedValue<AssignerWithPunctuatedWatermarks<T>> watermarksPunctuated,
				StreamingRuntimeContext runtimeContext,
				OffsetCommitMode offsetCommitMode) throws Exception {
			return mock(AbstractFetcher.class);
		}

		@Override
		protected List<KafkaTopicPartition> getKafkaPartitions(List<String> topics) {
			return partitions;
		}

		@Override
		protected boolean getIsAutoCommitEnabled() {
			return false;
		}
	}
}

/*
	THE CODE FOR FLINK 1.1

	@Test
	public void testRestoreFromFlink11() throws Exception {
		// --------------------------------------------------------------------
		//   prepare fake states
		// --------------------------------------------------------------------

		final HashMap<KafkaTopicPartition, Long> state1 = new HashMap<>();
		state1.put(new KafkaTopicPartition("abc", 13), 16768L);
		state1.put(new KafkaTopicPartition("def", 7), 987654321L);

		final OneShotLatch latch = new OneShotLatch();
		final AbstractFetcher<String, ?> fetcher = mock(AbstractFetcher.class);

		doAnswer(new Answer<Void>() {
			@Override
			public Void answer(InvocationOnMock invocation) throws Throwable {
				latch.trigger();
				return null;
			}
		}).when(fetcher).runFetchLoop();

		when(fetcher.snapshotCurrentState()).thenReturn(state1);

		final DummyFlinkKafkaConsumer<String> consumerFunction = new DummyFlinkKafkaConsumer<>(
			new FetcherFactory<String>() {
				private static final long serialVersionUID = -2803131905656983619L;

				@Override
				public AbstractFetcher<String, ?> createFetcher() {
					return fetcher;
				}
			});

		StreamSource<String, DummyFlinkKafkaConsumer<String>> consumerOperator =
			new StreamSource<>(consumerFunction);

		final OneInputStreamOperatorTestHarness<Void, String> testHarness =
			new OneInputStreamOperatorTestHarness<>(consumerOperator);

		testHarness.setTimeCharacteristic(TimeCharacteristic.ProcessingTime);

		testHarness.setup();
		testHarness.open();

		final Throwable[] error = new Throwable[1];

		// run the source asynchronously
		Thread runner = new Thread() {
			@Override
			public void run() {
				try {
					consumerFunction.run(new DummySourceContext() {
						@Override
						public void collect(String element) {
							latch.trigger();
						}
					});
				}
				catch (Throwable t) {
					t.printStackTrace();
					error[0] = t;
				}
			}
		};
		runner.start();

		if (!latch.isTriggered()) {
			latch.await();
		}

		StreamTaskState snapshot = testHarness.snapshot(0L, 0L);
		testHarness.snaphotToFile(snapshot, "src/test/resources/kafka-consumer-migration-test-flink1.1-snapshot-2");
		consumerOperator.run(new Object());

		consumerOperator.close();
		runner.join();

		System.out.println("Killed");
	}

	private static abstract class DummySourceContext
		implements SourceFunction.SourceContext<String> {

		private final Object lock = new Object();

		@Override
		public void collectWithTimestamp(String element, long timestamp) {
		}

		@Override
		public void emitWatermark(Watermark mark) {
		}

		@Override
		public Object getCheckpointLock() {
			return lock;
		}

		@Override
		public void close() {
		}
	}


	// ------------------------------------------------------------------------

	private interface FetcherFactory<T> extends Serializable {
		AbstractFetcher<T, ?> createFetcher();
	}

	private static class DummyFlinkKafkaConsumer<T> extends FlinkKafkaConsumerBase<T> {
		private static final long serialVersionUID = 1L;

		private final FetcherFactory<T> fetcherFactory;

		@SuppressWarnings("unchecked")
		public DummyFlinkKafkaConsumer(FetcherFactory<T> fetcherFactory) {
			super((KeyedDeserializationSchema< T >) mock(KeyedDeserializationSchema.class));

			final List<KafkaTopicPartition> partitions = new ArrayList<>();
			partitions.add(new KafkaTopicPartition("dummy-topic", 0));
			setSubscribedPartitions(partitions);

			this.fetcherFactory = fetcherFactory;
		}

		@Override
		protected AbstractFetcher<T, ?> createFetcher(SourceContext<T> sourceContext, List<KafkaTopicPartition> thisSubtaskPartitions, SerializedValue<AssignerWithPeriodicWatermarks<T>> watermarksPeriodic, SerializedValue<AssignerWithPunctuatedWatermarks<T>> watermarksPunctuated, StreamingRuntimeContext runtimeContext) throws Exception {
			return fetcherFactory.createFetcher();
		}
	}
* */