pulsar-client/src/main/java/org/apache/pulsar/client/impl/ReaderImpl.java

/*
 * 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.pulsar.client.impl;

import java.io.IOException;
import java.util.UUID;
import java.util.concurrent.CompletableFuture;
import java.util.concurrent.TimeUnit;
import java.util.function.Function;
import lombok.extern.slf4j.Slf4j;
import org.apache.commons.codec.digest.DigestUtils;
import org.apache.commons.lang3.StringUtils;
import org.apache.pulsar.client.api.BatchReceivePolicy;
import org.apache.pulsar.client.api.Consumer;
import org.apache.pulsar.client.api.KeySharedPolicy;
import org.apache.pulsar.client.api.Message;
import org.apache.pulsar.client.api.MessageId;
import org.apache.pulsar.client.api.MessageListener;
import org.apache.pulsar.client.api.PulsarClientException;
import org.apache.pulsar.client.api.Reader;
import org.apache.pulsar.client.api.ReaderListener;
import org.apache.pulsar.client.api.Schema;
import org.apache.pulsar.client.api.SubscriptionType;
import org.apache.pulsar.client.impl.conf.ConsumerConfigurationData;
import org.apache.pulsar.client.impl.conf.ReaderConfigurationData;
import org.apache.pulsar.client.util.ExecutorProvider;
import org.apache.pulsar.common.naming.TopicName;
import org.apache.pulsar.common.util.CompletableFutureCancellationHandler;

@Slf4j
public class ReaderImpl<T> implements Reader<T> {
    private static final BatchReceivePolicy DISABLED_BATCH_RECEIVE_POLICY = BatchReceivePolicy.builder()
            .timeout(0, TimeUnit.MILLISECONDS)
            .maxNumMessages(1)
            .build();
    private final ConsumerImpl<T> consumer;

    public ReaderImpl(PulsarClientImpl client, ReaderConfigurationData<T> readerConfiguration,
                      ExecutorProvider executorProvider, CompletableFuture<Consumer<T>> consumerFuture,
                      Schema<T> schema) {
        String subscription;
        if (StringUtils.isNotBlank(readerConfiguration.getSubscriptionName())) {
            subscription = readerConfiguration.getSubscriptionName();
        } else {
            subscription = "reader-" + DigestUtils.sha1Hex(UUID.randomUUID().toString()).substring(0, 10);
            if (StringUtils.isNotBlank(readerConfiguration.getSubscriptionRolePrefix())) {
                subscription = readerConfiguration.getSubscriptionRolePrefix() + "-" + subscription;
            }
        }

        ConsumerConfigurationData<T> consumerConfiguration = new ConsumerConfigurationData<>();
        consumerConfiguration.getTopicNames().add(readerConfiguration.getTopicName());
        consumerConfiguration.setSubscriptionName(subscription);
        consumerConfiguration.setSubscriptionType(SubscriptionType.Exclusive);
        consumerConfiguration.setSubscriptionMode(readerConfiguration.getSubscriptionMode());
        consumerConfiguration.setSubscriptionInitialPosition(readerConfiguration.getSubscriptionInitialPosition());
        consumerConfiguration.setReceiverQueueSize(readerConfiguration.getReceiverQueueSize());
        consumerConfiguration.setReadCompacted(readerConfiguration.isReadCompacted());
        consumerConfiguration.setPoolMessages(readerConfiguration.isPoolMessages());

        // chunking configuration
        consumerConfiguration.setMaxPendingChunkedMessage(readerConfiguration.getMaxPendingChunkedMessage());
        consumerConfiguration.setAutoAckOldestChunkedMessageOnQueueFull(
                readerConfiguration.isAutoAckOldestChunkedMessageOnQueueFull());
        consumerConfiguration.setExpireTimeOfIncompleteChunkedMessageMillis(
                readerConfiguration.getExpireTimeOfIncompleteChunkedMessageMillis());

        // Reader doesn't need any batch receiving behaviours
        // disable the batch receive timer for the ConsumerImpl instance wrapped by the ReaderImpl
        consumerConfiguration.setBatchReceivePolicy(DISABLED_BATCH_RECEIVE_POLICY);

        if (readerConfiguration.getReaderName() != null) {
            consumerConfiguration.setConsumerName(readerConfiguration.getReaderName());
        }

        if (readerConfiguration.isResetIncludeHead()) {
            consumerConfiguration.setResetIncludeHead(true);
        }

        if (readerConfiguration.getReaderListener() != null) {
            ReaderListener<T> readerListener = readerConfiguration.getReaderListener();
            consumerConfiguration.setMessageListener(new MessageListener<T>() {
                private static final long serialVersionUID = 1L;

                @Override
                public void received(Consumer<T> consumer, Message<T> msg) {
                    final MessageId messageId = msg.getMessageId();
                    readerListener.received(ReaderImpl.this, msg);
                    consumer.acknowledgeCumulativeAsync(messageId).exceptionally(ex -> {
                        log.error("[{}][{}] auto acknowledge message {} cumulative fail.", getTopic(),
                                getConsumer().getSubscription(), messageId, ex);
                        return null;
                    });
                }

                @Override
                public void reachedEndOfTopic(Consumer<T> consumer) {
                    readerListener.reachedEndOfTopic(ReaderImpl.this);
                }
            });
        }

        consumerConfiguration.setCryptoFailureAction(readerConfiguration.getCryptoFailureAction());
        if (readerConfiguration.getCryptoKeyReader() != null) {
            consumerConfiguration.setCryptoKeyReader(readerConfiguration.getCryptoKeyReader());
        }

        if (readerConfiguration.getMessageCrypto() != null) {
            consumerConfiguration.setMessageCrypto(readerConfiguration.getMessageCrypto());
        }

        if (readerConfiguration.getKeyHashRanges() != null) {
            consumerConfiguration.setKeySharedPolicy(
                    KeySharedPolicy
                            .stickyHashRange()
                            .ranges(readerConfiguration.getKeyHashRanges())
            );
        }

        ConsumerInterceptors<T> consumerInterceptors =
                ReaderInterceptorUtil.convertToConsumerInterceptors(
                        this, readerConfiguration.getReaderInterceptorList());
        final int partitionIdx = TopicName.getPartitionIndex(readerConfiguration.getTopicName());
        consumer = new ConsumerImpl<>(client, readerConfiguration.getTopicName(), consumerConfiguration,
                executorProvider, partitionIdx, false, false, consumerFuture,
                readerConfiguration.getStartMessageId(), readerConfiguration.getStartMessageFromRollbackDurationInSec(),
                schema, consumerInterceptors, true /* createTopicIfDoesNotExist */);
    }

    @Override
    public String getTopic() {
        return consumer.getTopic();
    }

    public ConsumerImpl<T> getConsumer() {
        return consumer;
    }

    @Override
    public boolean hasReachedEndOfTopic() {
        return consumer.hasReachedEndOfTopic();
    }

    @Override
    public Message<T> readNext() throws PulsarClientException {
        Message<T> msg = consumer.receive();

        // Acknowledge message immediately because the reader is based on non-durable subscription. When it reconnects,
        // it will specify the subscription position anyway
        consumer.acknowledgeCumulativeAsync(msg).exceptionally(ex -> {
            log.warn("[{}][{}] acknowledge message {} cumulative fail.", getTopic(),
                    getConsumer().getSubscription(), msg.getMessageId(), ex);
            return null;
        });
        return msg;
    }

    @Override
    public Message<T> readNext(int timeout, TimeUnit unit) throws PulsarClientException {
        Message<T> msg = consumer.receive(timeout, unit);

        if (msg != null) {
            consumer.acknowledgeCumulativeAsync(msg).exceptionally(ex -> {
                log.warn("[{}][{}] acknowledge message {} cumulative fail.", getTopic(),
                        getConsumer().getSubscription(), msg.getMessageId(), ex);
                return null;
            });
        }
        return msg;
    }

    @Override
    public CompletableFuture<Message<T>> readNextAsync() {
        CompletableFuture<Message<T>> originalFuture = consumer.receiveAsync();
        CompletableFuture<Message<T>> result = originalFuture.thenApply(msg -> {
            consumer.acknowledgeCumulativeAsync(msg)
                    .exceptionally(ex -> {
                        log.error("[{}][{}] acknowledge message {} cumulative fail.", getTopic(),
                                getConsumer().getSubscription(), msg.getMessageId(), ex);
                        return null;
                    });
            return msg;
        });
        CompletableFutureCancellationHandler handler = new CompletableFutureCancellationHandler();
        handler.attachToFuture(result);
        handler.setCancelAction(() -> originalFuture.cancel(false));
        return result;
    }

    @Override
    public void close() throws IOException {
        consumer.close();
    }

    @Override
    public CompletableFuture<Void> closeAsync() {
        return consumer.closeAsync();
    }

    @Override
    public boolean hasMessageAvailable() throws PulsarClientException {
        return consumer.hasMessageAvailable();
    }

    @Override
    public CompletableFuture<Boolean> hasMessageAvailableAsync() {
        return consumer.hasMessageAvailableAsync();
    }

    @Override
    public boolean isConnected() {
        return consumer.isConnected();
    }

    @Override
    public void seek(MessageId messageId) throws PulsarClientException {
        consumer.seek(messageId);
    }

    @Override
    public void seek(long timestamp) throws PulsarClientException {
        consumer.seek(timestamp);
    }

    @Override
    public void seek(Function<String, Object> function) throws PulsarClientException {
        consumer.seek(function);
    }

    @Override
    public CompletableFuture<Void> seekAsync(Function<String, Object> function) {
        return consumer.seekAsync(function);
    }

    @Override
    public CompletableFuture<Void> seekAsync(MessageId messageId) {
        return consumer.seekAsync(messageId);
    }

    @Override
    public CompletableFuture<Void> seekAsync(long timestamp) {
        return consumer.seekAsync(timestamp);
    }
}