com.expediagroup.rhapsody.kafka.acknowledgement.AbstractReceiverAcknowledgementStrategy Maven / Gradle / Ivy

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/**
 * Copyright 2019 Expedia, Inc.
 *
 * Licensed 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 com.expediagroup.rhapsody.kafka.acknowledgement;

import java.util.Map;
import java.util.function.Function;
import java.util.function.UnaryOperator;

import org.apache.kafka.clients.consumer.ConsumerRecord;
import org.reactivestreams.Publisher;

import com.expediagroup.rhapsody.api.Acknowledgeable;
import com.expediagroup.rhapsody.kafka.factory.AcknowledgeableConsumerRecordFactory;

import reactor.core.publisher.EmitterProcessor;
import reactor.core.publisher.Flux;
import reactor.core.publisher.FluxProcessor;
import reactor.core.publisher.FluxSink;
import reactor.kafka.receiver.ReceiverRecord;

abstract class AbstractReceiverAcknowledgementStrategy implements ReceiverAcknowledgementStrategy {

    // Note that transformation is deferred on a per-Subscription basis to avoid possible
    // complications due to lost Acknowledgers between Subscriptions
    @Override
    public final  Function>, ? extends Publisher>>>
    createRecordTransformer(Map properties) {
        AcknowledgeableConsumerRecordFactory acknowledgeableFactory = AcknowledgeableConsumerRecordFactory.create(properties);
        long maxInFlight = ReceiverAcknowledgementStrategy.loadMaxInFlightPerTopicPartition(properties).orElse(Long.MAX_VALUE);
        return source -> Flux.defer(() -> transform(source, acknowledgeableFactory, maxInFlight));
    }

    protected final  Publisher>>
    transform(Publisher> source, AcknowledgeableConsumerRecordFactory acknowledgeableFactory, long maxInFlight) {
        FluxProcessor>, Acknowledgeable>> manualProcessor = EmitterProcessor.create();
        FluxSink>> sink = manualProcessor.sink();
        return Flux.>from(source)
            .map(receiverRecord -> acknowledgeableFactory.create(receiverRecord, receiverRecord.receiverOffset()::acknowledge, sink::error))
            .mergeWith(manualProcessor)
            .transform(createOperator(maxInFlight));
    }

    protected abstract  UnaryOperator>>> createOperator(long maxInFlight);
}