Github user tillrohrmann commented on a diff in the pull request: https://github.com/apache/flink/pull/2629#discussion_r88718820 --- Diff: flink-streaming-java/src/main/java/org/apache/flink/streaming/api/operators/async/AsyncWaitOperator.java --- @@ -0,0 +1,224 @@ +/* + * 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.api.operators.async; + +import org.apache.flink.annotation.Internal; +import org.apache.flink.annotation.VisibleForTesting; +import org.apache.flink.api.common.state.ListState; +import org.apache.flink.api.common.state.ListStateDescriptor; +import org.apache.flink.api.common.typeutils.TypeSerializer; +import org.apache.flink.runtime.state.StateInitializationContext; +import org.apache.flink.runtime.state.StateSnapshotContext; +import org.apache.flink.streaming.api.datastream.AsyncDataStream; +import org.apache.flink.streaming.api.functions.async.AsyncFunction; +import org.apache.flink.streaming.api.graph.StreamConfig; +import org.apache.flink.streaming.api.operators.AbstractUdfStreamOperator; +import org.apache.flink.streaming.api.operators.ChainingStrategy; +import org.apache.flink.streaming.api.operators.OneInputStreamOperator; +import org.apache.flink.streaming.api.operators.Output; +import org.apache.flink.streaming.api.operators.TimestampedCollector; +import org.apache.flink.streaming.api.watermark.Watermark; +import org.apache.flink.streaming.runtime.streamrecord.LatencyMarker; +import org.apache.flink.streaming.runtime.streamrecord.StreamElement; +import org.apache.flink.streaming.runtime.streamrecord.StreamElementSerializer; +import org.apache.flink.streaming.runtime.streamrecord.StreamRecord; +import org.apache.flink.streaming.runtime.tasks.StreamTask; +import org.apache.flink.util.Preconditions; + +import java.util.Collection; + +@Internal +public class AsyncWaitOperator<IN, OUT> + extends AbstractUdfStreamOperator<OUT, AsyncFunction<IN, OUT>> + implements OneInputStreamOperator<IN, OUT> +{ + private final int DEFAULT_BUFFER_SIZE = 1000; + + private static final long serialVersionUID = 1L; + + private final static String STATE_NAME = "_async_wait_operator_state_"; + + /** + * {@link TypeSerializer} for inputs while making snapshots. + */ + private transient StreamElementSerializer<IN> inStreamElementSerializer; + + /** + * input stream elements from the state + */ + private transient ListState<StreamElement> recoveredStreamElements; + + private transient TimestampedCollector<OUT> collector; + + private transient AsyncCollectorBuffer<IN, OUT> buffer; + + /** + * Checkpoint lock from {@link StreamTask#lock} + */ + private transient Object checkpointLock; + + private int bufferSize = DEFAULT_BUFFER_SIZE; + private AsyncDataStream.OutputMode mode; + + /** + * For test only. Normally this flag is true, indicating that the Emitter Thread + * in the buffer will work. + */ + private boolean emitFlag = true; + + /** + * Test serializer used in unit test + */ + private StreamElementSerializer<IN> inStreamElementSerializerForTest; + + + public AsyncWaitOperator(AsyncFunction<IN, OUT> asyncFunction) { + super(asyncFunction); + chainingStrategy = ChainingStrategy.ALWAYS; + } + + public void setBufferSize(int size) { + Preconditions.checkArgument(size > 0, "The number of concurrent async operation should be greater than 0."); + bufferSize = size; + } + + public void setOutputMode(AsyncDataStream.OutputMode mode) { + this.mode = mode; + } + + @VisibleForTesting + public void setEmitFlag(boolean emitFlag) { + this.emitFlag = emitFlag; + } + + @VisibleForTesting + public void setInStreamElementSerializerForTest(StreamElementSerializer<IN> serializer) { + this.inStreamElementSerializerForTest = serializer; + } + + @Override + public void setup(StreamTask<?, ?> containingTask, StreamConfig config, Output<StreamRecord<OUT>> output) { + super.setup(containingTask, config, output); + + if (this.inStreamElementSerializerForTest != null) { + this.inStreamElementSerializer = this.inStreamElementSerializerForTest; + } + else { + this.inStreamElementSerializer = new StreamElementSerializer(this.getOperatorConfig().getTypeSerializerIn1(getUserCodeClassloader())); + } + + this.collector = new TimestampedCollector<>(output); + + this.checkpointLock = containingTask.getCheckpointLock(); + + this.buffer = new AsyncCollectorBuffer<>(bufferSize, mode, output, collector, this.checkpointLock, this); + + } + + @Override + public void open() throws Exception { + super.open(); + + // process stream elements from state + if (this.recoveredStreamElements != null) { + for (StreamElement element : this.recoveredStreamElements.get()) { + if (element.isRecord()) { + processElement(element.<IN>asRecord()); + } + else if (element.isWatermark()) { + processWatermark(element.asWatermark()); + } + else if (element.isLatencyMarker()) { + processLatencyMarker(element.asLatencyMarker()); + } + else { + throw new Exception("Unknown record type: "+element.getClass()); + } + } + this.recoveredStreamElements = null; + } + + + if (emitFlag) { + buffer.startEmitterThread(); + } + } + + @Override + public void processElement(StreamRecord<IN> element) throws Exception { + AsyncCollector<IN, OUT> collector = buffer.addStreamRecord(element); + + userFunction.asyncInvoke(element.getValue(), collector); + } + + @Override + public void processWatermark(Watermark mark) throws Exception { + buffer.addWatermark(mark); + } + + @Override + public void processLatencyMarker(LatencyMarker latencyMarker) throws Exception { + buffer.addLatencyMarker(latencyMarker); + } + + @Override + public void snapshotState(StateSnapshotContext context) throws Exception { + super.snapshotState(context); + + ListState<StreamElement> partitionableState = + getOperatorStateBackend().getOperatorState(new ListStateDescriptor<>(STATE_NAME, inStreamElementSerializer)); + partitionableState.clear(); + + Collection<StreamElement> elements = buffer.getStreamElementsInBuffer(); + for (StreamElement element : elements) { + partitionableState.add(element); + } + } + + @Override + public void initializeState(StateInitializationContext context) throws Exception { + recoveredStreamElements = + context.getManagedOperatorStateStore().getOperatorState(new ListStateDescriptor<>(STATE_NAME, inStreamElementSerializer)); + + } + + @Override + public void close() throws Exception { + // for test only, we do not have to wait until buffer is empty. + if (!emitFlag) { + return; + } --- End diff -- This is not good. Test code should not be part of the production code.
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