SteNicholas commented on a change in pull request #15924: URL: https://github.com/apache/flink/pull/15924#discussion_r633194823
########## File path: flink-connectors/flink-connector-base/src/main/java/org/apache/flink/connector/base/source/hybrid/HybridSourceReader.java ########## @@ -0,0 +1,201 @@ +/* + * 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.connector.base.source.hybrid; + +import org.apache.flink.api.connector.source.ReaderOutput; +import org.apache.flink.api.connector.source.SourceEvent; +import org.apache.flink.api.connector.source.SourceReader; +import org.apache.flink.api.connector.source.SourceReaderContext; +import org.apache.flink.api.connector.source.SourceSplit; +import org.apache.flink.core.io.InputStatus; +import org.apache.flink.util.Preconditions; + +import org.slf4j.Logger; +import org.slf4j.LoggerFactory; + +import java.util.ArrayList; +import java.util.List; +import java.util.concurrent.CompletableFuture; + +/** Hybrid source reader that delegates to the actual current source reader. */ Review comment: The comment of `HybridSourceReader` is confused because there is no concept of current source reader. ########## File path: flink-connectors/flink-connector-base/src/main/java/org/apache/flink/connector/base/source/hybrid/HybridSource.java ########## @@ -0,0 +1,213 @@ +/* + * 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.connector.base.source.hybrid; + +import org.apache.flink.api.connector.source.Boundedness; +import org.apache.flink.api.connector.source.Source; +import org.apache.flink.api.connector.source.SourceReader; +import org.apache.flink.api.connector.source.SourceReaderContext; +import org.apache.flink.api.connector.source.SourceSplit; +import org.apache.flink.api.connector.source.SplitEnumerator; +import org.apache.flink.api.connector.source.SplitEnumeratorContext; +import org.apache.flink.api.java.tuple.Tuple2; +import org.apache.flink.core.io.SimpleVersionedSerializer; +import org.apache.flink.util.Preconditions; + +import java.io.ByteArrayInputStream; +import java.io.ByteArrayOutputStream; +import java.io.DataInputStream; +import java.io.DataOutputStream; +import java.io.IOException; +import java.io.Serializable; +import java.util.ArrayList; +import java.util.Collections; +import java.util.List; +import java.util.function.Function; + +/** Hybrid source that switches underlying sources based on configurable source chain. */ +public class HybridSource<T> implements Source<T, HybridSourceSplit, HybridSourceEnumState> { + + private final SourceChain<T, ? extends SourceSplit, ?> sourceChain; + + public HybridSource(SourceChain<T, ? extends SourceSplit, ?> sourceChain) { Review comment: IMO, `SourceChain` shouldn't be generated from user side, which could be constructed in `HybridSource`. The constructor of `HybridSource` could be initial source or source list. ########## File path: flink-connectors/flink-connector-base/src/main/java/org/apache/flink/connector/base/source/hybrid/HybridSourceReader.java ########## @@ -0,0 +1,201 @@ +/* + * 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.connector.base.source.hybrid; + +import org.apache.flink.api.connector.source.ReaderOutput; +import org.apache.flink.api.connector.source.SourceEvent; +import org.apache.flink.api.connector.source.SourceReader; +import org.apache.flink.api.connector.source.SourceReaderContext; +import org.apache.flink.api.connector.source.SourceSplit; +import org.apache.flink.core.io.InputStatus; +import org.apache.flink.util.Preconditions; + +import org.slf4j.Logger; +import org.slf4j.LoggerFactory; + +import java.util.ArrayList; +import java.util.List; +import java.util.concurrent.CompletableFuture; + +/** Hybrid source reader that delegates to the actual current source reader. */ +public class HybridSourceReader<T, SplitT extends SourceSplit> + implements SourceReader<T, HybridSourceSplit<SplitT>> { + private static final Logger LOG = LoggerFactory.getLogger(HybridSourceReader.class); + private static final int SOURCE_READER_FINISHED_EVENT_DELAY = 250; Review comment: Could the value of `SOURCE_READER_FINISHED_EVENT_DELAY ` be configured by users? And why does this need the `SOURCE_READER_FINISHED_EVENT_DELAY`? ########## File path: flink-connectors/flink-connector-base/src/main/java/org/apache/flink/connector/base/source/hybrid/HybridSource.java ########## @@ -0,0 +1,213 @@ +/* + * 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.connector.base.source.hybrid; + +import org.apache.flink.api.connector.source.Boundedness; +import org.apache.flink.api.connector.source.Source; +import org.apache.flink.api.connector.source.SourceReader; +import org.apache.flink.api.connector.source.SourceReaderContext; +import org.apache.flink.api.connector.source.SourceSplit; +import org.apache.flink.api.connector.source.SplitEnumerator; +import org.apache.flink.api.connector.source.SplitEnumeratorContext; +import org.apache.flink.api.java.tuple.Tuple2; +import org.apache.flink.core.io.SimpleVersionedSerializer; +import org.apache.flink.util.Preconditions; + +import java.io.ByteArrayInputStream; +import java.io.ByteArrayOutputStream; +import java.io.DataInputStream; +import java.io.DataOutputStream; +import java.io.IOException; +import java.io.Serializable; +import java.util.ArrayList; +import java.util.Collections; +import java.util.List; +import java.util.function.Function; + +/** Hybrid source that switches underlying sources based on configurable source chain. */ +public class HybridSource<T> implements Source<T, HybridSourceSplit, HybridSourceEnumState> { + + private final SourceChain<T, ? extends SourceSplit, ?> sourceChain; + + public HybridSource(SourceChain<T, ? extends SourceSplit, ?> sourceChain) { + this.sourceChain = sourceChain; + } + + @Override + public Boundedness getBoundedness() { + for (Tuple2<Source<T, ? extends SourceSplit, ?>, ?> t : sourceChain.sources) { Review comment: The `getBoundedness` method should return the boundedness of the latest source, which is reasonable from user's perspective. ########## File path: flink-connectors/flink-connector-base/src/main/java/org/apache/flink/connector/base/source/hybrid/HybridSource.java ########## @@ -0,0 +1,213 @@ +/* + * 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.connector.base.source.hybrid; + +import org.apache.flink.api.connector.source.Boundedness; +import org.apache.flink.api.connector.source.Source; +import org.apache.flink.api.connector.source.SourceReader; +import org.apache.flink.api.connector.source.SourceReaderContext; +import org.apache.flink.api.connector.source.SourceSplit; +import org.apache.flink.api.connector.source.SplitEnumerator; +import org.apache.flink.api.connector.source.SplitEnumeratorContext; +import org.apache.flink.api.java.tuple.Tuple2; +import org.apache.flink.core.io.SimpleVersionedSerializer; +import org.apache.flink.util.Preconditions; + +import java.io.ByteArrayInputStream; +import java.io.ByteArrayOutputStream; +import java.io.DataInputStream; +import java.io.DataOutputStream; +import java.io.IOException; +import java.io.Serializable; +import java.util.ArrayList; +import java.util.Collections; +import java.util.List; +import java.util.function.Function; + +/** Hybrid source that switches underlying sources based on configurable source chain. */ +public class HybridSource<T> implements Source<T, HybridSourceSplit, HybridSourceEnumState> { + + private final SourceChain<T, ? extends SourceSplit, ?> sourceChain; + + public HybridSource(SourceChain<T, ? extends SourceSplit, ?> sourceChain) { + this.sourceChain = sourceChain; + } + + @Override + public Boundedness getBoundedness() { + for (Tuple2<Source<T, ? extends SourceSplit, ?>, ?> t : sourceChain.sources) { + if (t.f0.getBoundedness() == Boundedness.CONTINUOUS_UNBOUNDED) { + return Boundedness.CONTINUOUS_UNBOUNDED; + } + } + return Boundedness.BOUNDED; + } + + @Override + public SourceReader<T, HybridSourceSplit> createReader(SourceReaderContext readerContext) + throws Exception { + List<SourceReader<?, ? extends SourceSplit>> readers = new ArrayList<>(); + for (Tuple2<Source<T, ? extends SourceSplit, ?>, ?> source : sourceChain.sources) { + readers.add(source.f0.createReader(readerContext)); + } + return new HybridSourceReader(readerContext, readers); + } + + @Override + public SplitEnumerator<HybridSourceSplit, HybridSourceEnumState> createEnumerator( + SplitEnumeratorContext<HybridSourceSplit> enumContext) { + return new HybridSourceSplitEnumerator(enumContext, sourceChain); + } + + @Override + public SplitEnumerator<HybridSourceSplit, HybridSourceEnumState> restoreEnumerator( + SplitEnumeratorContext<HybridSourceSplit> enumContext, HybridSourceEnumState checkpoint) + throws Exception { + return new HybridSourceSplitEnumerator( + enumContext, sourceChain, checkpoint.getCurrentSourceIndex()); + } + + @Override + public SimpleVersionedSerializer<HybridSourceSplit> getSplitSerializer() { + List<SimpleVersionedSerializer<SourceSplit>> serializers = new ArrayList<>(); + sourceChain.sources.forEach( + t -> serializers.add(castSerializer(t.f0.getSplitSerializer()))); + return new SplitSerializerWrapper<>(serializers); + } + + @Override + public SimpleVersionedSerializer<HybridSourceEnumState> getEnumeratorCheckpointSerializer() { + List<SimpleVersionedSerializer<Object>> serializers = new ArrayList<>(); + sourceChain.sources.forEach( + t -> serializers.add(castSerializer(t.f0.getEnumeratorCheckpointSerializer()))); + return new HybridSourceEnumStateSerializer(serializers); + } + + private static <T> SimpleVersionedSerializer<T> castSerializer( + SimpleVersionedSerializer<? extends T> s) { + @SuppressWarnings("rawtypes") + SimpleVersionedSerializer s1 = s; + return s1; + } + + /** Serializes splits by delegating to the source-indexed split serializer. */ + public static class SplitSerializerWrapper<SplitT extends SourceSplit> + implements SimpleVersionedSerializer<HybridSourceSplit> { + + final List<SimpleVersionedSerializer<SourceSplit>> serializers; + + public SplitSerializerWrapper(List<SimpleVersionedSerializer<SourceSplit>> serializers) { + this.serializers = serializers; + } + + @Override + public int getVersion() { + return 0; + } + + @Override + public byte[] serialize(HybridSourceSplit split) throws IOException { + try (ByteArrayOutputStream baos = new ByteArrayOutputStream(); + DataOutputStream out = new DataOutputStream(baos)) { + out.writeInt(split.sourceIndex()); + out.writeInt(serializerOf(split.sourceIndex()).getVersion()); + byte[] serializedSplit = + serializerOf(split.sourceIndex()).serialize(split.getWrappedSplit()); + out.writeInt(serializedSplit.length); + out.write(serializedSplit); + return baos.toByteArray(); + } + } + + @Override + public HybridSourceSplit deserialize(int version, byte[] serialized) throws IOException { + try (ByteArrayInputStream bais = new ByteArrayInputStream(serialized); + DataInputStream in = new DataInputStream(bais)) { + int sourceIndex = in.readInt(); + int nestedVersion = in.readInt(); + int length = in.readInt(); + byte[] splitBytes = new byte[length]; + in.readFully(splitBytes); + SourceSplit split = + serializerOf(sourceIndex).deserialize(nestedVersion, splitBytes); + return new HybridSourceSplit(sourceIndex, split); + } + } + + private SimpleVersionedSerializer<SourceSplit> serializerOf(int sourceIndex) { + Preconditions.checkArgument(sourceIndex < serializers.size()); + return serializers.get(sourceIndex); + } + } + + /** + * Converts checkpoint between sources to transfer end position to next source's start position. + * Only required for dynamic position transfer at time of switching, otherwise source can be + * preconfigured with a start position during job submission. + */ + public interface CheckpointConverter<InCheckpointT, OutCheckpointT> Review comment: `CheckpointConverter` interface could be replaced with `Function`, because this interface is essentially a `Function`. ########## File path: flink-connectors/flink-connector-base/src/main/java/org/apache/flink/connector/base/source/hybrid/HybridSourceReader.java ########## @@ -0,0 +1,201 @@ +/* + * 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.connector.base.source.hybrid; + +import org.apache.flink.api.connector.source.ReaderOutput; +import org.apache.flink.api.connector.source.SourceEvent; +import org.apache.flink.api.connector.source.SourceReader; +import org.apache.flink.api.connector.source.SourceReaderContext; +import org.apache.flink.api.connector.source.SourceSplit; +import org.apache.flink.core.io.InputStatus; +import org.apache.flink.util.Preconditions; + +import org.slf4j.Logger; +import org.slf4j.LoggerFactory; + +import java.util.ArrayList; +import java.util.List; +import java.util.concurrent.CompletableFuture; + +/** Hybrid source reader that delegates to the actual current source reader. */ +public class HybridSourceReader<T, SplitT extends SourceSplit> + implements SourceReader<T, HybridSourceSplit<SplitT>> { + private static final Logger LOG = LoggerFactory.getLogger(HybridSourceReader.class); + private static final int SOURCE_READER_FINISHED_EVENT_DELAY = 250; + private SourceReaderContext readerContext; + private List<SourceReader<?, SplitT>> realReaders; + private int currentSourceIndex = -1; + private long lastCheckpointId = -1; + private SourceReader<?, SplitT> currentReader; + private long lastReaderFinishedMs; + + public HybridSourceReader( + SourceReaderContext readerContext, List<SourceReader<?, SplitT>> readers) { + this.readerContext = readerContext; + this.realReaders = readers; + } + + @Override + public void start() { + setCurrentReader(0); + } + + @Override + public InputStatus pollNext(ReaderOutput output) throws Exception { + InputStatus status = currentReader.pollNext(output); + if (status == InputStatus.END_OF_INPUT) { + // trap END_OF_INPUT if this wasn't the final reader + LOG.debug( + "End of input subtask={} sourceIndex={} {}", + readerContext.getIndexOfSubtask(), + currentSourceIndex, + currentReader); + if (currentSourceIndex + 1 < realReaders.size()) { + // signal coordinator to advance readers + long currentMillis = System.currentTimeMillis(); + if (lastReaderFinishedMs + SOURCE_READER_FINISHED_EVENT_DELAY < currentMillis) { + lastReaderFinishedMs = currentMillis; + readerContext.sendSourceEventToCoordinator( + new SourceReaderFinishedEvent(currentSourceIndex, lastCheckpointId)); + } + // more data will be available from the next reader + return InputStatus.MORE_AVAILABLE; + } + } + return status; + } + + @Override + public List<HybridSourceSplit<SplitT>> snapshotState(long checkpointId) { + this.lastCheckpointId = checkpointId; + List<SplitT> state = currentReader.snapshotState(checkpointId); + return wrappedSplits(currentSourceIndex, state); + } + + public static <SplitT extends SourceSplit> List<HybridSourceSplit<SplitT>> wrappedSplits( + int readerIndex, List<SplitT> state) { + List<HybridSourceSplit<SplitT>> wrappedSplits = new ArrayList<>(state.size()); + for (SplitT split : state) { + wrappedSplits.add(new HybridSourceSplit<>(readerIndex, split)); + } + return wrappedSplits; + } + + public static <SplitT extends SourceSplit> List<SplitT> unwrappedSplits( + List<HybridSourceSplit<SplitT>> splits) { + List<SplitT> unwrappedSplits = new ArrayList<>(splits.size()); + for (HybridSourceSplit<SplitT> split : splits) { + unwrappedSplits.add(split.getWrappedSplit()); + } + return unwrappedSplits; + } + + @Override + public CompletableFuture<Void> isAvailable() { + return currentReader.isAvailable(); + } + + @Override + public void addSplits(List<HybridSourceSplit<SplitT>> splits) { + LOG.info( + "### Adding splits subtask={} sourceIndex={} {} {}", + readerContext.getIndexOfSubtask(), + currentSourceIndex, + currentReader, + splits); + List<SplitT> realSplits = new ArrayList<>(splits.size()); + for (HybridSourceSplit split : splits) { + Preconditions.checkState( + split.sourceIndex() == currentSourceIndex, + "Split %s while current source is %s", + split, + currentSourceIndex); + realSplits.add((SplitT) split.getWrappedSplit()); + } + currentReader.addSplits(realSplits); + } + + @Override + public void notifyNoMoreSplits() { + currentReader.notifyNoMoreSplits(); + LOG.debug( + "No more splits for reader subtask={} sourceIndex={} {}", + readerContext.getIndexOfSubtask(), + currentSourceIndex, + currentReader); + } + + @Override + public void handleSourceEvents(SourceEvent sourceEvent) { + if (sourceEvent instanceof SwitchSourceEvent) { + SwitchSourceEvent sse = (SwitchSourceEvent) sourceEvent; + LOG.debug( + "Switch source event: subtask={} sourceIndex={}", + readerContext.getIndexOfSubtask(), + sse.sourceIndex()); + setCurrentReader(sse.sourceIndex()); Review comment: IMO, the source reader switching should be executed before sending `SourceReaderFinishedEvent`, not receiving the `SwitchSourceEvent`. ########## File path: flink-connectors/flink-connector-base/src/main/java/org/apache/flink/connector/base/source/hybrid/HybridSourceSplitEnumerator.java ########## @@ -0,0 +1,390 @@ +/* + * 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.connector.base.source.hybrid; + +import org.apache.flink.api.connector.source.ReaderInfo; +import org.apache.flink.api.connector.source.Source; +import org.apache.flink.api.connector.source.SourceEvent; +import org.apache.flink.api.connector.source.SourceSplit; +import org.apache.flink.api.connector.source.SplitEnumerator; +import org.apache.flink.api.connector.source.SplitEnumeratorContext; +import org.apache.flink.api.connector.source.SplitsAssignment; +import org.apache.flink.metrics.MetricGroup; +import org.apache.flink.util.Preconditions; + +import org.slf4j.Logger; +import org.slf4j.LoggerFactory; + +import java.io.IOException; +import java.util.ArrayList; +import java.util.Arrays; +import java.util.Collections; +import java.util.HashMap; +import java.util.HashSet; +import java.util.List; +import java.util.Map; +import java.util.TreeMap; +import java.util.concurrent.Callable; +import java.util.function.BiConsumer; + +/** + * Wraps the actual split enumerators and facilitates source switching. Enumerators are created + * lazily when source switch occurs to support runtime position conversion. + */ +public class HybridSourceSplitEnumerator<SplitT extends SourceSplit, CheckpointT> + implements SplitEnumerator<HybridSourceSplit<SplitT>, HybridSourceEnumState> { + private static final Logger LOG = LoggerFactory.getLogger(HybridSourceSplitEnumerator.class); + + private final SplitEnumeratorContext<HybridSourceSplit> context; + private final HybridSource.SourceChain<?, SplitT, Object> sourceChain; + // TODO: SourceCoordinatorContext does not provide access to current assignments + private final Map<Integer, List<HybridSourceSplit<SplitT>>> assignments; + private final Map<Integer, TreeMap<Integer, List<HybridSourceSplit<SplitT>>>> pendingSplits; + private final HashSet<Integer> pendingReaders; + private int currentSourceIndex; + private SplitEnumerator<SplitT, Object> currentEnumerator; + + public HybridSourceSplitEnumerator( + SplitEnumeratorContext<HybridSourceSplit> context, + HybridSource.SourceChain<?, SplitT, Object> sourceChain) { + this(context, sourceChain, 0); + } + + public HybridSourceSplitEnumerator( + SplitEnumeratorContext<HybridSourceSplit> context, + HybridSource.SourceChain<?, SplitT, Object> sourceChain, + int initialSourceIndex) { + Preconditions.checkArgument(initialSourceIndex < sourceChain.sources.size()); + this.context = context; + this.sourceChain = sourceChain; + this.currentSourceIndex = initialSourceIndex; + this.assignments = new HashMap<>(); + this.pendingSplits = new HashMap<>(); + this.pendingReaders = new HashSet<>(); + } + + @Override + public void start() { + switchEnumerator(); + } + + @Override + public void handleSplitRequest(int subtaskId, String requesterHostname) { + LOG.debug( + "handleSplitRequest subtask={} sourceIndex={} pendingSplits={}", + subtaskId, + currentSourceIndex, + pendingSplits); + // TODO: test coverage for on demand split assignment + assignPendingSplits(subtaskId); + currentEnumerator.handleSplitRequest(subtaskId, requesterHostname); + } + + @Override + public void addSplitsBack(List<HybridSourceSplit<SplitT>> splits, int subtaskId) { + LOG.debug("Adding splits back for subtask={} {}", subtaskId, splits); + // Splits returned can belong to multiple sources, after switching since last checkpoint + TreeMap<Integer, List<HybridSourceSplit<SplitT>>> splitsBySourceIndex = new TreeMap<>(); + + for (HybridSourceSplit<SplitT> split : splits) { + splitsBySourceIndex + .computeIfAbsent(split.sourceIndex(), k -> new ArrayList<>()) + .add(split); + } + + splitsBySourceIndex.forEach( + (k, splitsPerSource) -> { + if (k == currentSourceIndex) { + currentEnumerator.addSplitsBack( + HybridSourceReader.unwrappedSplits(splitsPerSource), subtaskId); + } else { + pendingSplits + .computeIfAbsent(subtaskId, sourceIndex -> new TreeMap<>()) + .put(k, splitsPerSource); + if (context.registeredReaders().containsKey(subtaskId)) { + assignPendingSplits(subtaskId); + } + } + }); + } + + @Override + public void addReader(int subtaskId) { + LOG.debug("addReader subtaskId={}", subtaskId); + if (pendingSplits.isEmpty()) { + context.sendEventToSourceReader(subtaskId, new SwitchSourceEvent(currentSourceIndex)); + LOG.debug("Adding reader {} to enumerator {}", subtaskId, currentSourceIndex); + currentEnumerator.addReader(subtaskId); + } else { + // Defer adding reader to the current enumerator until splits belonging to earlier + // enumerators that were added back have been processed + pendingReaders.add(subtaskId); + assignPendingSplits(subtaskId); + } + } + + private void assignPendingSplits(int subtaskId) { + TreeMap<Integer, List<HybridSourceSplit<SplitT>>> splitsBySource = + pendingSplits.get(subtaskId); + if (splitsBySource != null) { + int sourceIndex = splitsBySource.firstKey(); + List<HybridSourceSplit<SplitT>> splits = + Preconditions.checkNotNull(splitsBySource.get(sourceIndex)); + LOG.debug("Assigning pending splits subtask={} {}", subtaskId, splits); + context.sendEventToSourceReader(subtaskId, new SwitchSourceEvent(sourceIndex)); + context.assignSplits( + new SplitsAssignment<HybridSourceSplit>( + Collections.singletonMap(subtaskId, (List) splits))); + context.signalNoMoreSplits(subtaskId); + // Empty collection indicates that splits have been assigned + splits.clear(); + } + } + + @Override + public HybridSourceEnumState snapshotState(long checkpointId) throws Exception { + Object enumState = currentEnumerator.snapshotState(checkpointId); + return new HybridSourceEnumState(currentSourceIndex, enumState); + } + + @Override + public void handleSourceEvent(int subtaskId, SourceEvent sourceEvent) { + if (sourceEvent instanceof SourceReaderFinishedEvent) { + SourceReaderFinishedEvent srfe = (SourceReaderFinishedEvent) sourceEvent; + if (srfe.sourceIndex() != currentSourceIndex) { + if (srfe.sourceIndex() < currentSourceIndex) { + // Assign pending splits if any + TreeMap<Integer, List<HybridSourceSplit<SplitT>>> splitsBySource = + pendingSplits.get(subtaskId); + if (splitsBySource != null) { + List<HybridSourceSplit<SplitT>> splits = + splitsBySource.get(srfe.sourceIndex()); + if (splits != null && splits.isEmpty()) { + // Splits have been processed by the reader + splitsBySource.remove(srfe.sourceIndex()); + } + if (splitsBySource.isEmpty()) { + pendingSplits.remove(subtaskId); + } else { + Integer nextSubtaskSourceIndex = splitsBySource.firstKey(); + LOG.debug( + "Restore subtask={}, sourceIndex={}", + subtaskId, + nextSubtaskSourceIndex); + context.sendEventToSourceReader( + subtaskId, new SwitchSourceEvent(nextSubtaskSourceIndex)); + assignPendingSplits(subtaskId); + } + } + // Once all pending splits have been processed, add the readers to the current + // enumerator, which may in turn trigger new split assignments + if (!pendingReaders.isEmpty() && pendingSplits.isEmpty()) { + // Advance pending readers to current enumerator + LOG.debug( + "Adding pending readers {} to enumerator currentSourceIndex={}", + pendingReaders, + currentSourceIndex); + for (int pendingReaderSubtaskId : pendingReaders) { + context.sendEventToSourceReader( + pendingReaderSubtaskId, + new SwitchSourceEvent(currentSourceIndex)); + } + for (int pendingReaderSubtaskId : pendingReaders) { + currentEnumerator.addReader(pendingReaderSubtaskId); + } + pendingReaders.clear(); + } + } else { + // source already switched + LOG.debug("Ignoring out of order source event {}", srfe); + } + return; + } + this.assignments.remove(subtaskId); + LOG.info( + "Reader finished for subtask {} remaining assignments {}", + subtaskId, + assignments); + if (this.assignments.isEmpty()) { + LOG.debug("No assignments remaining, ready to switch source!"); + if (currentSourceIndex + 1 < sourceChain.sources.size()) { + switchEnumerator(); + // switch all readers prior to sending split assignments + for (int i = 0; i < context.currentParallelism(); i++) { + context.sendEventToSourceReader( + i, new SwitchSourceEvent(currentSourceIndex)); + } + // trigger split assignment, + // (initially happens as part of subtask/reader registration) + for (int i = 0; i < context.currentParallelism(); i++) { + LOG.debug("adding reader subtask={} sourceIndex={}", i, currentSourceIndex); + currentEnumerator.addReader(i); + } + } + } + } else { + currentEnumerator.handleSourceEvent(subtaskId, sourceEvent); + } + } + + @Override + public void close() throws IOException { + currentEnumerator.close(); + } + + private void switchEnumerator() { + + Object enumeratorState = null; + if (currentEnumerator != null) { + try { + enumeratorState = currentEnumerator.snapshotState(-1); + currentEnumerator.close(); + } catch (Exception e) { + throw new RuntimeException(e); + } + currentEnumerator = null; + currentSourceIndex++; + } + + SplitEnumeratorContextProxy delegatingContext = + new SplitEnumeratorContextProxy(currentSourceIndex, context, assignments); + Source<?, ? extends SourceSplit, Object> source = + (Source) sourceChain.sources.get(currentSourceIndex).f0; + HybridSource.CheckpointConverter<Object, Object> converter = Review comment: `HybridSource.CheckpointConverter<Object, Object>` could be replaced with `HybridSource.CheckpointConverter<?, ?> converter `. -- This is an automated message from the Apache Git Service. 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