dannycranmer commented on a change in pull request #13102: URL: https://github.com/apache/flink/pull/13102#discussion_r490193060
########## File path: flink-connectors/flink-connector-kinesis/src/main/java/org/apache/flink/streaming/connectors/kinesis/internals/publisher/fanout/FanOutShardSubscriber.java ########## @@ -0,0 +1,466 @@ +/* + * 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.kinesis.internals.publisher.fanout; + +import org.apache.flink.annotation.Internal; +import org.apache.flink.streaming.connectors.kinesis.proxy.KinesisProxyV2; +import org.apache.flink.streaming.connectors.kinesis.proxy.KinesisProxyV2Interface; +import org.apache.flink.util.Preconditions; + +import org.reactivestreams.Subscriber; +import org.reactivestreams.Subscription; +import org.slf4j.Logger; +import org.slf4j.LoggerFactory; +import software.amazon.awssdk.services.kinesis.KinesisAsyncClient; +import software.amazon.awssdk.services.kinesis.model.ResourceNotFoundException; +import software.amazon.awssdk.services.kinesis.model.StartingPosition; +import software.amazon.awssdk.services.kinesis.model.SubscribeToShardEvent; +import software.amazon.awssdk.services.kinesis.model.SubscribeToShardEventStream; +import software.amazon.awssdk.services.kinesis.model.SubscribeToShardRequest; +import software.amazon.awssdk.services.kinesis.model.SubscribeToShardResponseHandler; + +import java.util.concurrent.BlockingQueue; +import java.util.concurrent.CompletionException; +import java.util.concurrent.CountDownLatch; +import java.util.concurrent.ExecutionException; +import java.util.concurrent.LinkedBlockingQueue; +import java.util.concurrent.atomic.AtomicReference; +import java.util.function.Consumer; + +import static java.util.concurrent.TimeUnit.SECONDS; + +/** + * This class is responsible for acquiring an Enhanced Fan Out subscription and consuming records from a shard. + * A queue is used to buffer records between the Kinesis Proxy and Flink application. This allows processing + * to be separated from consumption; errors thrown in the consumption layer do not propagate up to application. + * + * <pre>{@code [ + * | ----------- Source Connector Thread ----------- | | --- KinesisAsyncClient Thread(s) -- | + * | FanOutRecordPublisher | FanOutShardSubscription | == blocking queue == | KinesisProxyV2 | KinesisAsyncClient | + * ]}</pre> + * <p> + * Three types of message are passed over the queue for inter-thread communication: + * <ul> + * <li>{@link SubscriptionNextEvent} - passes data from the network to the consumer</li> + * <li>{@link SubscriptionCompleteEvent} - indicates a subscription has expired</li> + * <li>{@link SubscriptionErrorEvent} - passes an exception from the network to the consumer</li> + * </ul> + * </p> + * <p> + * The blocking queue has a maximum capacity of 1 record. + * This allows backpressure to be applied closer to the network stack and results in record prefetch. + * At maximum capacity we will have three {@link SubscribeToShardEvent} in memory (per instance of this class): + * <ul> + * <li>1 event being processed by the consumer</li> + * <li>1 event enqueued in the blocking queue</li> + * <li>1 event being added to the queue by the network (blocking)</li> + * </ul> + * </p> + */ +@Internal +public class FanOutShardSubscriber { Review comment: Where do you see these warning? I do not see them in terminal output, are they IntelliJ inspections? ---------------------------------------------------------------- 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. For queries about this service, please contact Infrastructure at: [email protected]
