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| * 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 * |
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| * specific language governing permissions and limitations * |
| * under the License. * |
| ****************************************************************/ |
| |
| package org.apache.james.events; |
| |
| import static org.apache.james.backends.rabbitmq.Constants.AUTO_DELETE; |
| import static org.apache.james.backends.rabbitmq.Constants.DURABLE; |
| import static org.apache.james.backends.rabbitmq.Constants.EXCLUSIVE; |
| import static org.apache.james.backends.rabbitmq.Constants.REQUEUE; |
| |
| import java.util.Objects; |
| import java.util.Optional; |
| import java.util.function.Predicate; |
| |
| import org.apache.james.backends.rabbitmq.RabbitMQConfiguration; |
| import org.apache.james.backends.rabbitmq.ReactorRabbitMQChannelPool; |
| import org.apache.james.backends.rabbitmq.ReceiverProvider; |
| import org.apache.james.util.MDCBuilder; |
| import org.slf4j.Logger; |
| import org.slf4j.LoggerFactory; |
| |
| import com.google.common.base.Preconditions; |
| |
| import reactor.core.Disposable; |
| import reactor.core.publisher.Flux; |
| import reactor.core.publisher.Mono; |
| import reactor.core.scheduler.Schedulers; |
| import reactor.rabbitmq.AcknowledgableDelivery; |
| import reactor.rabbitmq.ConsumeOptions; |
| import reactor.rabbitmq.QueueSpecification; |
| import reactor.rabbitmq.Receiver; |
| import reactor.rabbitmq.Sender; |
| import reactor.util.retry.Retry; |
| |
| class GroupRegistration implements Registration { |
| |
| static class WorkQueueName { |
| private final String prefix; |
| private final Group group; |
| |
| WorkQueueName(String prefix, Group group) { |
| this.prefix = prefix; |
| Preconditions.checkNotNull(group, "Group must be specified"); |
| this.group = group; |
| } |
| |
| String asString() { |
| return prefix + "-workQueue-" + group.asString(); |
| } |
| } |
| |
| private static final Logger LOGGER = LoggerFactory.getLogger(GroupRegistration.class); |
| static final String RETRY_COUNT = "retry-count"; |
| static final int DEFAULT_RETRY_COUNT = 0; |
| |
| private final NamingStrategy namingStrategy; |
| private final ReactorRabbitMQChannelPool channelPool; |
| private final EventListener.ReactiveEventListener listener; |
| private final WorkQueueName queueName; |
| private final Runnable unregisterGroup; |
| private final EventSerializer eventSerializer; |
| private final GroupConsumerRetry retryHandler; |
| private final WaitDelayGenerator delayGenerator; |
| private final Group group; |
| private final RetryBackoffConfiguration retryBackoff; |
| private final ListenerExecutor listenerExecutor; |
| private final RabbitMQConfiguration configuration; |
| private Optional<Disposable> receiverSubscriber; |
| private final ReceiverProvider receiverProvider; |
| |
| GroupRegistration(NamingStrategy namingStrategy, ReactorRabbitMQChannelPool channelPool, Sender sender, ReceiverProvider receiverProvider, EventSerializer eventSerializer, |
| EventListener.ReactiveEventListener listener, Group group, RetryBackoffConfiguration retryBackoff, |
| EventDeadLetters eventDeadLetters, |
| Runnable unregisterGroup, ListenerExecutor listenerExecutor, RabbitMQConfiguration configuration) { |
| this.namingStrategy = namingStrategy; |
| this.channelPool = channelPool; |
| this.eventSerializer = eventSerializer; |
| this.listener = listener; |
| this.configuration = configuration; |
| this.queueName = namingStrategy.workQueue(group); |
| this.receiverProvider = receiverProvider; |
| this.retryBackoff = retryBackoff; |
| this.listenerExecutor = listenerExecutor; |
| this.receiverSubscriber = Optional.empty(); |
| this.unregisterGroup = unregisterGroup; |
| this.retryHandler = new GroupConsumerRetry(namingStrategy, sender, group, retryBackoff, eventDeadLetters, eventSerializer); |
| this.delayGenerator = WaitDelayGenerator.of(retryBackoff); |
| this.group = group; |
| } |
| |
| GroupRegistration start() { |
| receiverSubscriber = Optional |
| .of(createGroupWorkQueue() |
| .then(retryHandler.createRetryExchange(queueName)) |
| .then(Mono.fromCallable(this::consumeWorkQueue)) |
| .retryWhen(Retry.backoff(retryBackoff.getMaxRetries(), retryBackoff.getFirstBackoff()).jitter(retryBackoff.getJitterFactor()).scheduler(Schedulers.elastic())) |
| .block()); |
| return this; |
| } |
| |
| void restart() { |
| Optional<Disposable> previousSubscriber = this.receiverSubscriber; |
| receiverSubscriber = Optional.of(consumeWorkQueue()); |
| previousSubscriber |
| .filter(Predicate.not(Disposable::isDisposed)) |
| .ifPresent(Disposable::dispose); |
| } |
| |
| private Mono<Void> createGroupWorkQueue() { |
| return channelPool.createWorkQueue( |
| QueueSpecification.queue(queueName.asString()) |
| .durable(DURABLE) |
| .exclusive(!EXCLUSIVE) |
| .autoDelete(!AUTO_DELETE) |
| .arguments(configuration.workQueueArgumentsBuilder(!AUTO_DELETE) |
| .deadLetter(namingStrategy.deadLetterExchange()) |
| .build())); |
| } |
| |
| private Disposable consumeWorkQueue() { |
| return Flux.using( |
| receiverProvider::createReceiver, |
| receiver -> receiver.consumeManualAck(queueName.asString(), new ConsumeOptions().qos(EventBus.EXECUTION_RATE)), |
| Receiver::close) |
| .publishOn(Schedulers.parallel()) |
| .filter(delivery -> Objects.nonNull(delivery.getBody())) |
| .flatMap(this::deliver, EventBus.EXECUTION_RATE) |
| .subscribeOn(Schedulers.elastic()) |
| .subscribe(); |
| } |
| |
| private Mono<Void> deliver(AcknowledgableDelivery acknowledgableDelivery) { |
| byte[] eventAsBytes = acknowledgableDelivery.getBody(); |
| int currentRetryCount = getRetryCount(acknowledgableDelivery); |
| |
| return deserializeEvent(eventAsBytes) |
| .flatMap(event -> delayGenerator.delayIfHaveTo(currentRetryCount) |
| .flatMap(any -> runListenerReliably(currentRetryCount, event)) |
| .then(Mono.<Void>fromRunnable(acknowledgableDelivery::ack).subscribeOn(Schedulers.elastic()))) |
| .onErrorResume(e -> { |
| LOGGER.error("Unable to process delivery for group {}", group, e); |
| return Mono.fromRunnable(() -> acknowledgableDelivery.nack(!REQUEUE)) |
| .subscribeOn(Schedulers.elastic()) |
| .then(); |
| }); |
| } |
| |
| public Mono<Void> runListenerReliably(int currentRetryCount, Event event) { |
| return runListener(event) |
| .onErrorResume(throwable -> retryHandler.handleRetry(event, currentRetryCount, throwable)); |
| } |
| |
| private Mono<Event> deserializeEvent(byte[] eventAsBytes) { |
| return Mono.fromCallable(() -> eventSerializer.fromBytes(eventAsBytes)) |
| .subscribeOn(Schedulers.parallel()); |
| } |
| |
| Mono<Void> reDeliver(Event event) { |
| return retryHandler.retryOrStoreToDeadLetter(event, DEFAULT_RETRY_COUNT); |
| } |
| |
| private Mono<Void> runListener(Event event) { |
| return listenerExecutor.execute( |
| listener, |
| MDCBuilder.create() |
| .addToContext(EventBus.StructuredLoggingFields.GROUP, group.asString()), |
| event); |
| } |
| |
| private int getRetryCount(AcknowledgableDelivery acknowledgableDelivery) { |
| return Optional.ofNullable(acknowledgableDelivery.getProperties().getHeaders()) |
| .flatMap(headers -> Optional.ofNullable(headers.get(RETRY_COUNT))) |
| .filter(Integer.class::isInstance) |
| .map(Integer.class::cast) |
| .orElse(DEFAULT_RETRY_COUNT); |
| } |
| |
| @Override |
| public void unregister() { |
| receiverSubscriber.filter(Predicate.not(Disposable::isDisposed)) |
| .ifPresent(Disposable::dispose); |
| unregisterGroup.run(); |
| } |
| } |