Amar3tto commented on code in PR #17828: URL: https://github.com/apache/beam/pull/17828#discussion_r954750796
########## sdks/java/io/sparkreceiver/src/main/java/org/apache/beam/sdk/io/sparkreceiver/ReadFromSparkReceiverWithOffsetDoFn.java: ########## @@ -0,0 +1,221 @@ +/* + * 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.beam.sdk.io.sparkreceiver; + +import static org.apache.beam.sdk.util.Preconditions.checkStateNotNull; + +import java.util.Queue; +import java.util.concurrent.ConcurrentLinkedQueue; +import java.util.concurrent.TimeUnit; +import org.apache.beam.sdk.coders.Coder; +import org.apache.beam.sdk.io.range.OffsetRange; +import org.apache.beam.sdk.transforms.DoFn; +import org.apache.beam.sdk.transforms.DoFn.UnboundedPerElement; +import org.apache.beam.sdk.transforms.SerializableFunction; +import org.apache.beam.sdk.transforms.splittabledofn.ManualWatermarkEstimator; +import org.apache.beam.sdk.transforms.splittabledofn.OffsetRangeTracker; +import org.apache.beam.sdk.transforms.splittabledofn.RestrictionTracker; +import org.apache.beam.sdk.transforms.splittabledofn.WatermarkEstimator; +import org.apache.beam.sdk.transforms.splittabledofn.WatermarkEstimators; +import org.apache.beam.sdk.transforms.windowing.BoundedWindow; +import org.apache.spark.SparkConf; +import org.apache.spark.streaming.receiver.Receiver; +import org.checkerframework.checker.nullness.qual.Nullable; +import org.joda.time.Instant; +import org.slf4j.Logger; +import org.slf4j.LoggerFactory; + +/** + * A SplittableDoFn which reads from {@link Receiver} that implements {@link HasOffset}. By default, + * a {@link WatermarkEstimators.Manual} watermark estimator is used to track watermark. + * + * <p>Initial range The initial range is {@code [0, Long.MAX_VALUE)} + * + * <p>Resume Processing Every time the sparkConsumer.hasRecords() returns false, {@link + * ReadFromSparkReceiverWithOffsetDoFn} will move to process the next element. + */ +@UnboundedPerElement +class ReadFromSparkReceiverWithOffsetDoFn<V> extends DoFn<byte[], V> { + + private static final Logger LOG = + LoggerFactory.getLogger(ReadFromSparkReceiverWithOffsetDoFn.class); + + /** Constant waiting time after the {@link Receiver} starts. Required to prepare for polling */ + private static final int START_POLL_TIMEOUT_MS = 1000; + + private final SerializableFunction<Instant, WatermarkEstimator<Instant>> + createWatermarkEstimatorFn; + private final SerializableFunction<V, Long> getOffsetFn; + private final SerializableFunction<V, Instant> getWatermarkFn; + private final ReceiverBuilder<V, ? extends Receiver<V>> sparkReceiverBuilder; + + ReadFromSparkReceiverWithOffsetDoFn(SparkReceiverIO.Read<V> transform) { + createWatermarkEstimatorFn = WatermarkEstimators.Manual::new; + + ReceiverBuilder<V, ? extends Receiver<V>> sparkReceiverBuilder = + transform.getSparkReceiverBuilder(); + checkStateNotNull(sparkReceiverBuilder, "Spark Receiver Builder can't be null!"); + this.sparkReceiverBuilder = sparkReceiverBuilder; + + SerializableFunction<V, Long> getOffsetFn = transform.getGetOffsetFn(); + checkStateNotNull(getOffsetFn, "Get offset fn can't be null!"); + this.getOffsetFn = getOffsetFn; + + SerializableFunction<V, Instant> getWatermarkFn = transform.getWatermarkFn(); + if (getWatermarkFn == null) { + getWatermarkFn = input -> Instant.now(); + } + this.getWatermarkFn = getWatermarkFn; + } + + @GetInitialRestriction + public OffsetRange initialRestriction(@Element byte[] element) { + return new OffsetRange(0, Long.MAX_VALUE); + } + + @GetInitialWatermarkEstimatorState + public Instant getInitialWatermarkEstimatorState(@Timestamp Instant currentElementTimestamp) { + return currentElementTimestamp; + } + + @NewWatermarkEstimator + public WatermarkEstimator<Instant> newWatermarkEstimator( + @WatermarkEstimatorState Instant watermarkEstimatorState) { + return createWatermarkEstimatorFn.apply(ensureTimestampWithinBounds(watermarkEstimatorState)); + } + + @GetSize + public double getSize(@Element byte[] element, @Restriction OffsetRange offsetRange) { + return restrictionTracker(element, offsetRange).getProgress().getWorkRemaining(); + } + + @NewTracker + public OffsetRangeTracker restrictionTracker( + @Element byte[] element, @Restriction OffsetRange restriction) { + return new OffsetRangeTracker(restriction); + } + + @GetRestrictionCoder + public Coder<OffsetRange> restrictionCoder() { + return new OffsetRange.Coder(); + } + + // Need to do an unchecked cast from Object + // because org.apache.spark.streaming.receiver.ReceiverSupervisor accepts Object in push methods + @SuppressWarnings("unchecked") + private static class SparkConsumerWithOffset<V> implements SparkConsumer<V> { + private final Queue<V> recordsQueue; + private @Nullable Receiver<V> sparkReceiver; + private final Long startOffset; + + SparkConsumerWithOffset(Long startOffset) { + this.startOffset = startOffset; + this.recordsQueue = new ConcurrentLinkedQueue<>(); + } + + @Override + public boolean hasRecords() { + return !recordsQueue.isEmpty(); + } + + @Override + public @Nullable V poll() { + return recordsQueue.poll(); + } + + @Override + public void start(Receiver<V> sparkReceiver) { + this.sparkReceiver = sparkReceiver; + try { + new WrappedSupervisor( + sparkReceiver, + new SparkConf(), + objects -> { + V record = (V) objects[0]; + recordsQueue.offer(record); + return null; + }); + } catch (Exception e) { + LOG.error("Can not init Spark Receiver!", e); + } + ((HasOffset) sparkReceiver).setStartOffset(startOffset); + sparkReceiver.supervisor().startReceiver(); + try { + TimeUnit.MILLISECONDS.sleep(START_POLL_TIMEOUT_MS); + } catch (InterruptedException e) { + LOG.error("SparkReceiver was interrupted before polling started", e); + } + } + + @Override + public void stop() { + if (sparkReceiver != null) { + sparkReceiver.stop("SparkReceiver is stopped."); + } + recordsQueue.clear(); Review Comment: At this moment all records for the current restriction should be already read from the queue. Here we are stopping the Receiver and clearing the queue because it is not needed anymore. -- This is an automated message from the Apache Git Service. To respond to the message, please log on to GitHub and use the URL above to go to the specific comment. To unsubscribe, e-mail: [email protected] For queries about this service, please contact Infrastructure at: [email protected]
