kirktrue commented on code in PR #14406: URL: https://github.com/apache/kafka/pull/14406#discussion_r1366262621
########## clients/src/main/java/org/apache/kafka/clients/consumer/internals/ConsumerNetworkThread.java: ########## @@ -0,0 +1,241 @@ +/* + * 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; + +import org.apache.kafka.clients.KafkaClient; +import org.apache.kafka.clients.consumer.internals.events.ApplicationEvent; +import org.apache.kafka.clients.consumer.internals.events.ApplicationEventProcessor; +import org.apache.kafka.clients.consumer.internals.events.BackgroundEvent; +import org.apache.kafka.common.KafkaException; +import org.apache.kafka.common.errors.WakeupException; +import org.apache.kafka.common.internals.IdempotentCloser; +import org.apache.kafka.common.requests.AbstractRequest; +import org.apache.kafka.common.utils.KafkaThread; +import org.apache.kafka.common.utils.LogContext; +import org.apache.kafka.common.utils.Time; +import org.apache.kafka.common.utils.Timer; +import org.slf4j.Logger; + +import java.io.Closeable; +import java.time.Duration; +import java.util.Collection; +import java.util.List; +import java.util.Objects; +import java.util.Optional; +import java.util.concurrent.Future; +import java.util.function.Supplier; +import java.util.stream.Collectors; + +import static org.apache.kafka.clients.consumer.internals.ConsumerUtils.DEFAULT_CLOSE_TIMEOUT_MS; +import static org.apache.kafka.common.utils.Utils.closeQuietly; + +/** + * Background thread runnable that consumes {@link ApplicationEvent} and produces {@link BackgroundEvent}. It + * uses an event loop to consume and produce events, and poll the network client to handle network IO. + */ +public class ConsumerNetworkThread extends KafkaThread implements Closeable { + + private static final long MAX_POLL_TIMEOUT_MS = 5000; + private static final String BACKGROUND_THREAD_NAME = "consumer_background_thread"; + private final Time time; + private final Logger log; + private final Supplier<ApplicationEventProcessor> applicationEventProcessorSupplier; + private final Supplier<NetworkClientDelegate> networkClientDelegateSupplier; + private final Supplier<RequestManagers> requestManagersSupplier; + private ApplicationEventProcessor applicationEventProcessor; + private NetworkClientDelegate networkClientDelegate; + private RequestManagers requestManagers; + private volatile boolean running; + private final IdempotentCloser closer = new IdempotentCloser(); + private volatile Duration closeTimeout = Duration.ofMillis(DEFAULT_CLOSE_TIMEOUT_MS); + + public ConsumerNetworkThread(LogContext logContext, + Time time, + Supplier<ApplicationEventProcessor> applicationEventProcessorSupplier, + Supplier<NetworkClientDelegate> networkClientDelegateSupplier, + Supplier<RequestManagers> requestManagersSupplier) { + super(BACKGROUND_THREAD_NAME, true); + this.time = time; + this.log = logContext.logger(getClass()); + this.applicationEventProcessorSupplier = applicationEventProcessorSupplier; + this.networkClientDelegateSupplier = networkClientDelegateSupplier; + this.requestManagersSupplier = requestManagersSupplier; + } + + @Override + public void run() { + closer.assertOpen("Consumer network thread is already closed"); + running = true; + + try { + log.debug("Consumer network thread started"); + + // Wait until we're securely in the background network thread to initialize these objects... + initializeResources(); + + while (running) { + try { + runOnce(); + } catch (final WakeupException e) { + log.debug("WakeupException caught, consumer network thread won't be interrupted"); + // swallow the wakeup exception to prevent killing the thread. + } + } + } catch (final Throwable t) { + log.error("The consumer network thread failed due to unexpected error", t); + throw new KafkaException(t); + } finally { + cleanup(); + } + } + + void initializeResources() { + applicationEventProcessor = applicationEventProcessorSupplier.get(); + networkClientDelegate = networkClientDelegateSupplier.get(); + requestManagers = requestManagersSupplier.get(); + } + + /** + * Poll and process the {@link ApplicationEvent application events}. It performs the following tasks: + * + * <ol> + * <li> + * Drains and processes all the events from the application thread's application event queue via + * {@link ApplicationEventProcessor} + * </li> + * <li> + * Iterate through the {@link RequestManager} list and invoke {@link RequestManager#poll(long)} to get + * the {@link NetworkClientDelegate.UnsentRequest} list and the poll time for the network poll + * </li> + * <li> + * Stage each {@link AbstractRequest.Builder request} to be sent via + * {@link NetworkClientDelegate#addAll(List)} + * </li> + * <li> + * Poll the client via {@link KafkaClient#poll(long, long)} to send the requests, as well as + * retrieve any available responses + * </li> + * </ol> + */ + void runOnce() { + // If there are errors processing any events, the error will be thrown immediately. This will have + // the effect of closing the background thread. + applicationEventProcessor.process(); + + final long currentTimeMs = time.milliseconds(); + final long pollWaitTimeMs = requestManagers.entries().stream() + .filter(Optional::isPresent) + .map(Optional::get) + .map(rm -> rm.poll(currentTimeMs)) + .map(networkClientDelegate::addAll) + .reduce(MAX_POLL_TIMEOUT_MS, Math::min); + networkClientDelegate.poll(pollWaitTimeMs, currentTimeMs); + } + + /** + * Performs any network I/O that is needed at the time of close for the consumer: + * + * <ol> + * <li> + * Iterate through the {@link RequestManager} list and invoke {@link RequestManager#pollOnClose()} + * to get the {@link NetworkClientDelegate.UnsentRequest} list and the poll time for the network poll + * </li> + * <li> + * Stage each {@link AbstractRequest.Builder request} to be sent via + * {@link NetworkClientDelegate#addAll(List)} + * </li> + * <li> + * {@link KafkaClient#poll(long, long) Poll the client} to send the requests, as well as + * retrieve any available responses + * </li> + * <li> + * Continuously {@link KafkaClient#poll(long, long) poll the client} as long as the + * {@link Timer#notExpired() timer hasn't expired} to retrieve the responses + * </li> + * </ol> + */ + // Visible for testing + static void runAtClose(final Collection<Optional<? extends RequestManager>> requestManagers, + final NetworkClientDelegate networkClientDelegate, + final Timer timer) { + // These are the optional outgoing requests at the + List<NetworkClientDelegate.PollResult> pollResults = requestManagers.stream() + .filter(Optional::isPresent) + .map(Optional::get) + .map(RequestManager::pollOnClose) + .collect(Collectors.toList()); + long pollWaitTimeMs = pollResults.stream() + .map(networkClientDelegate::addAll) + .reduce(MAX_POLL_TIMEOUT_MS, Math::min); + pollWaitTimeMs = Math.min(pollWaitTimeMs, timer.remainingMs()); + networkClientDelegate.poll(pollWaitTimeMs, timer.currentTimeMs()); + timer.update(); + + List<Future<?>> requestFutures = pollResults.stream() + .flatMap(fads -> fads.unsentRequests.stream()) + .map(NetworkClientDelegate.UnsentRequest::future) + .collect(Collectors.toList()); + + // Poll to ensure that request has been written to the socket. Wait until either the timer has expired or until + // all requests have received a response. + while (timer.notExpired() && !requestFutures.stream().allMatch(Future::isDone)) { + networkClientDelegate.poll(timer.remainingMs(), timer.currentTimeMs()); + timer.update(); + } + } + + public boolean isRunning() { + return running; + } + + public void wakeup() { + // The network client can be null if the initializeResources method has not yet been called. + if (networkClientDelegate != null) + networkClientDelegate.wakeup(); + } + + @Override + public void close() { + close(closeTimeout); + } + + public void close(final Duration timeout) { + Objects.requireNonNull(timeout, "Close timeout for consumer network thread must be non-null"); + + closer.close( + () -> closeInternal(timeout), + () -> log.warn("The consumer network thread was already closed") + ); + } + + private void closeInternal(final Duration timeout) { + log.trace("Signaling the consumer network thread to close in {}ms", timeout.toMillis()); + running = false; + closeTimeout = timeout; + wakeup(); Review Comment: Yes. I've made the change that on `close()`, the application thread will wait for the network thread to finish its cleanup, up to the given timeout. -- 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
