junrao commented on code in PR #14406: URL: https://github.com/apache/kafka/pull/14406#discussion_r1367516322
########## clients/src/main/java/org/apache/kafka/clients/consumer/internals/events/ApplicationEventHandler.java: ########## @@ -0,0 +1,115 @@ +/* + * 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.kafka.clients.consumer.internals.events; + +import org.apache.kafka.clients.consumer.internals.ConsumerNetworkThread; +import org.apache.kafka.clients.consumer.internals.NetworkClientDelegate; +import org.apache.kafka.clients.consumer.internals.RequestManagers; +import org.apache.kafka.common.internals.IdempotentCloser; +import org.apache.kafka.common.utils.LogContext; +import org.apache.kafka.common.utils.Time; +import org.apache.kafka.common.utils.Timer; +import org.apache.kafka.common.utils.Utils; +import org.slf4j.Logger; + +import java.io.Closeable; +import java.time.Duration; +import java.util.Objects; +import java.util.concurrent.BlockingQueue; +import java.util.concurrent.Future; +import java.util.concurrent.TimeUnit; +import java.util.function.Supplier; + +/** + * An event handler that receives {@link ApplicationEvent application events} from the application thread which + * are then readable from the {@link ApplicationEventProcessor} in the {@link ConsumerNetworkThread network thread}. + */ +public class ApplicationEventHandler implements Closeable { + + private final Logger log; + private final BlockingQueue<ApplicationEvent> applicationEventQueue; + private final ConsumerNetworkThread networkThread; + private final IdempotentCloser closer = new IdempotentCloser(); + + public ApplicationEventHandler(final LogContext logContext, + final Time time, + final BlockingQueue<ApplicationEvent> applicationEventQueue, + final Supplier<ApplicationEventProcessor> applicationEventProcessorSupplier, + final Supplier<NetworkClientDelegate> networkClientDelegateSupplier, + final Supplier<RequestManagers> requestManagersSupplier) { + this.log = logContext.logger(ApplicationEventHandler.class); + this.applicationEventQueue = applicationEventQueue; + this.networkThread = new ConsumerNetworkThread(logContext, + time, + applicationEventProcessorSupplier, + networkClientDelegateSupplier, + requestManagersSupplier); + this.networkThread.start(); + } + + /** + * Add an {@link ApplicationEvent} to the handler and then internally invoke {@link #wakeup} to alert the + * network I/O thread that it has something to process. + * + * @param event An {@link ApplicationEvent} created by the application thread + */ + public void add(final ApplicationEvent event) { + Objects.requireNonNull(event, "ApplicationEvent provided to add must be non-null"); + log.trace("Enqueued event: {}", event); + applicationEventQueue.add(event); + wakeup(); + } + + /** + * Wakeup the {@link ConsumerNetworkThread network I/O thread} to pull the event from the queue. + */ + public void wakeup() { Review Comment: `wakeup` => `wakeupNetworkThread` ? ########## clients/src/main/java/org/apache/kafka/clients/consumer/internals/PrototypeAsyncConsumer.java: ########## @@ -633,56 +829,178 @@ public void assign(Collection<TopicPartition> partitions) { throw new IllegalArgumentException("Topic partitions to assign to cannot have null or empty topic"); } - // TODO: implementation of refactored Fetcher will be included in forthcoming commits. - // fetcher.clearBufferedDataForUnassignedPartitions(partitions); + // Clear the buffered data which are not a part of newly assigned topics + final Set<TopicPartition> currentTopicPartitions = new HashSet<>(); + + for (TopicPartition tp : subscriptions.assignedPartitions()) { + if (partitions.contains(tp)) + currentTopicPartitions.add(tp); + } + + fetchBuffer.retainAll(currentTopicPartitions); // assignment change event will trigger autocommit if it is configured and the group id is specified. This is // to make sure offsets of topic partitions the consumer is unsubscribing from are committed since there will - // be no following rebalance - eventHandler.add(new AssignmentChangeApplicationEvent(this.subscriptions.allConsumed(), time.milliseconds())); + // be no following rebalance. + // + // See the ApplicationEventProcessor.process() method that handles this event for more detail. + applicationEventHandler.add(new AssignmentChangeApplicationEvent(subscriptions.allConsumed(), time.milliseconds())); log.info("Assigned to partition(s): {}", join(partitions, ", ")); - if (this.subscriptions.assignFromUser(new HashSet<>(partitions))) - eventHandler.add(new NewTopicsMetadataUpdateRequestEvent()); + if (subscriptions.assignFromUser(new HashSet<>(partitions))) + applicationEventHandler.add(new NewTopicsMetadataUpdateRequestEvent()); } @Override - public void subscribe(Pattern pattern, ConsumerRebalanceListener callback) { - throw new KafkaException("method not implemented"); + public void subscribe(Pattern pattern, ConsumerRebalanceListener listener) { + maybeThrowInvalidGroupIdException(); + if (pattern == null || pattern.toString().isEmpty()) + throw new IllegalArgumentException("Topic pattern to subscribe to cannot be " + (pattern == null ? + "null" : "empty")); + + throwIfNoAssignorsConfigured(); + log.info("Subscribed to pattern: '{}'", pattern); + subscriptions.subscribe(pattern, listener); + updatePatternSubscription(metadata.fetch()); + metadata.requestUpdateForNewTopics(); + } + + /** + * TODO: remove this when we implement the KIP-848 protocol. + * + * <p> + * The contents of this method are shamelessly stolen from + * {@link ConsumerCoordinator#updatePatternSubscription(Cluster)} and are used here because we won't have access + * to a {@link ConsumerCoordinator} in this code. Perhaps it could be moved to a ConsumerUtils class? + * + * @param cluster Cluster from which we get the topics + */ + private void updatePatternSubscription(Cluster cluster) { + final Set<String> topicsToSubscribe = cluster.topics().stream() + .filter(subscriptions::matchesSubscribedPattern) + .collect(Collectors.toSet()); + if (subscriptions.subscribeFromPattern(topicsToSubscribe)) + metadata.requestUpdateForNewTopics(); } @Override public void subscribe(Pattern pattern) { - throw new KafkaException("method not implemented"); + subscribe(pattern, new NoOpConsumerRebalanceListener()); } @Override public void unsubscribe() { - throw new KafkaException("method not implemented"); + fetchBuffer.retainAll(Collections.emptySet()); + subscriptions.unsubscribe(); } @Override @Deprecated - public ConsumerRecords<K, V> poll(long timeout) { - throw new KafkaException("method not implemented"); + public ConsumerRecords<K, V> poll(final long timeoutMs) { + return poll(Duration.ofMillis(timeoutMs)); } // Visible for testing WakeupTrigger wakeupTrigger() { return wakeupTrigger; } - private static <K, V> ClusterResourceListeners configureClusterResourceListeners( - final Deserializer<K> keyDeserializer, - final Deserializer<V> valueDeserializer, - final List<?>... candidateLists) { - ClusterResourceListeners clusterResourceListeners = new ClusterResourceListeners(); - for (List<?> candidateList: candidateLists) - clusterResourceListeners.maybeAddAll(candidateList); + private Fetch<K, V> pollForFetches(Timer timer) { + long pollTimeout = timer.remainingMs(); + + // if data is available already, return it immediately + final Fetch<K, V> fetch = collectFetch(); + if (!fetch.isEmpty()) { + return fetch; + } + + // We do not want to be stuck blocking in poll if we are missing some positions + // since the offset lookup may be backing off after a failure - clusterResourceListeners.maybeAdd(keyDeserializer); - clusterResourceListeners.maybeAdd(valueDeserializer); - return clusterResourceListeners; + // NOTE: the use of cachedSubscriptionHasAllFetchPositions means we MUST call + // updateAssignmentMetadataIfNeeded before this method. + if (!cachedSubscriptionHasAllFetchPositions && pollTimeout > retryBackoffMs) { + pollTimeout = retryBackoffMs; + } + + log.trace("Polling for fetches with timeout {}", pollTimeout); + + Timer pollTimer = time.timer(pollTimeout); + + // Wait a bit for some fetched data to arrive, as there may not be anything immediately available. Note the + // use of a shorter, dedicated "pollTimer" here which updates "timer" so that calling method (poll) will + // correctly handle the overall timeout. + try { + fetchBuffer.awaitNotEmpty(pollTimer); + } catch (InterruptException e) { + log.trace("Timeout during fetch", e); + } finally { + timer.update(pollTimer.currentTimeMs()); + } + + return collectFetch(); + } + + /** + * Perform the "{@link FetchCollector#collectFetch(FetchBuffer) fetch collection}" step by reading raw data out + * of the {@link #fetchBuffer}, converting it to a well-formed {@link CompletedFetch}, validating that it and + * the internal {@link SubscriptionState state} are correct, and then converting it all into a {@link Fetch} + * for returning. + * + * <p/> + * + * Note that if the {@link Fetch#isEmpty() is not empty}, this method will + * {@link ApplicationEventHandler#wakeup() wake up} the {@link ConsumerNetworkThread} before retuning. This is + * done as an optimization so that the <em>next round of data can be pre-fetched</em>. + */ + private Fetch<K, V> collectFetch() { + final Fetch<K, V> fetch = fetchCollector.collectFetch(fetchBuffer); + + if (!fetch.isEmpty()) { + // Notify the network thread to wake up and start the next round of fetching. + applicationEventHandler.wakeup(); Review Comment: This doesn't seem quite right. It's possible for a fetchRequest to return no data. In that case, if we don't wake up the the network thread, it may not be able to send the next fetch request for a long time. ########## clients/src/main/java/org/apache/kafka/clients/consumer/internals/OffsetsRequestManager.java: ########## @@ -188,7 +194,14 @@ public CompletableFuture<Map<TopicPartition, OffsetAndTimestamp>> fetchOffsets( * this function (ex. {@link org.apache.kafka.common.errors.TopicAuthorizationException}) */ public void resetPositionsIfNeeded() { - Map<TopicPartition, Long> offsetResetTimestamps = offsetFetcherUtils.getOffsetResetTimestamp(); + Map<TopicPartition, Long> offsetResetTimestamps; + + try { + offsetResetTimestamps = offsetFetcherUtils.getOffsetResetTimestamp(); Review Comment: [auto.offset.reset](https://kafka.apache.org/documentation/#consumerconfigs_auto.offset.reset) has 3 options: `latest`, `earliest`, `none`. It's possible for a user to choose `none`, which means "throw exception to the consumer if no previous offset is found for the consumer's group". But in that case, `offsetFetcherUtils.getOffsetResetTimestamp` just ignores that partition and won't reset it forever. We need to throw an exception so that the user knows. It's a bit of weird configuration since it means a consumer can't really consume for the very first time with this option. However, I tested it out with the existing consumer and it does throw an exception. ``` bin/kafka-console-consumer.sh --consumer-property auto.offset.reset=none --bootstrap-server localhost:9092 --topic test [2023-10-20 15:30:07,088] ERROR Error processing message, terminating consumer process: (kafka.tools.ConsoleConsumer$) org.apache.kafka.clients.consumer.NoOffsetForPartitionException: Undefined offset with no reset policy for partitions: [test-0] at org.apache.kafka.clients.consumer.internals.SubscriptionState.resetInitializingPositions(SubscriptionState.java:711) at org.apache.kafka.clients.consumer.KafkaConsumer.updateFetchPositions(KafkaConsumer.java:2459) at org.apache.kafka.clients.consumer.KafkaConsumer.updateAssignmentMetadataIfNeeded(KafkaConsumer.java:1243) at org.apache.kafka.clients.consumer.KafkaConsumer.poll(KafkaConsumer.java:1198) at org.apache.kafka.clients.consumer.KafkaConsumer.poll(KafkaConsumer.java:1178) at kafka.tools.ConsoleConsumer$ConsumerWrapper.receive(ConsoleConsumer.scala:473) at kafka.tools.ConsoleConsumer$.process(ConsoleConsumer.scala:103) at kafka.tools.ConsoleConsumer$.run(ConsoleConsumer.scala:77) at kafka.tools.ConsoleConsumer$.main(ConsoleConsumer.scala:54) at kafka.tools.ConsoleConsumer.main(ConsoleConsumer.scala) ``` -- 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: jira-unsubscr...@kafka.apache.org For queries about this service, please contact Infrastructure at: us...@infra.apache.org
