聊聊spring for kafka對producer的封裝與集成

時間 2019-11-07

標籤聊聊 spring kafka producer 封裝集成欄目 Spring 简体版

原文原文鏈接

序

本文主要解析一下spring for apache kafka對原生的kafka client producer的封裝與集成。java

producer工廠

spring-kafka-1.2.3.RELEASE-sources.jar!/org/springframework/kafka/core/DefaultKafkaProducerFactory.javaspring

public class DefaultKafkaProducerFactory<K, V> implements ProducerFactory<K, V>, Lifecycle, DisposableBean {
    @Override
    public void destroy() throws Exception { //NOSONAR
        CloseSafeProducer<K, V> producer = this.producer;
        this.producer = null;
        if (producer != null) {
            producer.delegate.close(this.physicalCloseTimeout, TimeUnit.SECONDS);
        }
    }


    @Override
    public void start() {
        this.running = true;
    }


    @Override
    public void stop() {
        try {
            destroy();
        }
        catch (Exception e) {
            logger.error("Exception while stopping producer", e);
        }
    }


    @Override
    public boolean isRunning() {
        return this.running;
    }

    @Override
    public Producer<K, V> createProducer() {
        if (this.producer == null) {
            synchronized (this) {
                if (this.producer == null) {
                    this.producer = new CloseSafeProducer<K, V>(createKafkaProducer());
                }
            }
        }
        return this.producer;
    }
}

集成spring的第一步就是集成到spring容器託管，而後跟隨spring容器的生命週期正常啓動和銷燬。這裏建立了CloseSafeProducer，它實際的操做都委託給kafka producerapache

KafkaTemplate

spring-kafka-1.2.3.RELEASE-sources.jar!/org/springframework/kafka/core/KafkaTemplate.java
實現了以下接口ide

public interface KafkaOperations<K, V> {

    /**
     * Send the data to the default topic with no key or partition.
     * @param data The data.
     * @return a Future for the {@link SendResult}.
     */
    ListenableFuture<SendResult<K, V>> sendDefault(V data);

    /**
     * Send the data to the default topic with the provided key and no partition.
     * @param key the key.
     * @param data The data.
     * @return a Future for the {@link SendResult}.
     */
    ListenableFuture<SendResult<K, V>> sendDefault(K key, V data);

    /**
     * Send the data to the default topic with the provided key and partition.
     * @param partition the partition.
     * @param key the key.
     * @param data the data.
     * @return a Future for the {@link SendResult}.
     */
    ListenableFuture<SendResult<K, V>> sendDefault(int partition, K key, V data);

    /**
     * Send the data to the provided topic with no key or partition.
     * @param topic the topic.
     * @param data The data.
     * @return a Future for the {@link SendResult}.
     */
    ListenableFuture<SendResult<K, V>> send(String topic, V data);

    /**
     * Send the data to the provided topic with the provided key and no partition.
     * @param topic the topic.
     * @param key the key.
     * @param data The data.
     * @return a Future for the {@link SendResult}.
     */
    ListenableFuture<SendResult<K, V>> send(String topic, K key, V data);

    /**
     * Send the data to the provided topic with the provided partition and no key.
     * @param topic the topic.
     * @param partition the partition.
     * @param data The data.
     * @return a Future for the {@link SendResult}.
     */
    ListenableFuture<SendResult<K, V>> send(String topic, int partition, V data);

    /**
     * Send the data to the provided topic with the provided key and partition.
     * @param topic the topic.
     * @param partition the partition.
     * @param key the key.
     * @param data the data.
     * @return a Future for the {@link SendResult}.
     */
    ListenableFuture<SendResult<K, V>> send(String topic, int partition, K key, V data);

    /**
     * Send a message with routing information in message headers. The message payload
     * may be converted before sending.
     * @param message the message to send.
     * @return a Future for the {@link SendResult}.
     * @see org.springframework.kafka.support.KafkaHeaders#TOPIC
     * @see org.springframework.kafka.support.KafkaHeaders#PARTITION_ID
     * @see org.springframework.kafka.support.KafkaHeaders#MESSAGE_KEY
     */
    ListenableFuture<SendResult<K, V>> send(Message<?> message);

    /**
     * See {@link Producer#partitionsFor(String)}.
     * @param topic the topic.
     * @return the partition info.
     * @since 1.1
     */
    List<PartitionInfo> partitionsFor(String topic);

    /**
     * See {@link Producer#metrics()}.
     * @return the metrics.
     * @since 1.1
     */
    Map<MetricName, ? extends Metric> metrics();

    /**
     * Execute some arbitrary operation(s) on the producer and return the result.
     * @param callback the callback.
     * @param <T> the result type.
     * @return the result.
     * @since 1.1
     */
    <T> T execute(ProducerCallback<K, V, T> callback);

    /**
     * Flush the producer.
     */
    void flush();

    /**
     * A callback for executing arbitrary operations on the {@link Producer}.
     * @param <K> the key type.
     * @param <V> the value type.
     * @param <T> the return type.
     * @since 1.1
     */
    interface ProducerCallback<K, V, T> {

        T doInKafka(Producer<K, V> producer);

    }

}

主要的send方法以下，這就是spring對producer的主要包裝的地方：this

/**
     * Send the producer record.
     * @param producerRecord the producer record.
     * @return a Future for the {@link RecordMetadata}.
     */
    protected ListenableFuture<SendResult<K, V>> doSend(final ProducerRecord<K, V> producerRecord) {
        final Producer<K, V> producer = getTheProducer();
        if (this.logger.isTraceEnabled()) {
            this.logger.trace("Sending: " + producerRecord);
        }
        final SettableListenableFuture<SendResult<K, V>> future = new SettableListenableFuture<>();
        producer.send(producerRecord, new Callback() {

            @Override
            public void onCompletion(RecordMetadata metadata, Exception exception) {
                try {
                    if (exception == null) {
                        future.set(new SendResult<>(producerRecord, metadata));
                        if (KafkaTemplate.this.producerListener != null
                                && KafkaTemplate.this.producerListener.isInterestedInSuccess()) {
                            KafkaTemplate.this.producerListener.onSuccess(producerRecord.topic(),
                                    producerRecord.partition(), producerRecord.key(), producerRecord.value(), metadata);
                        }
                    }
                    else {
                        future.setException(new KafkaProducerException(producerRecord, "Failed to send", exception));
                        if (KafkaTemplate.this.producerListener != null) {
                            KafkaTemplate.this.producerListener.onError(producerRecord.topic(),
                                    producerRecord.partition(),
                                    producerRecord.key(),
                                    producerRecord.value(),
                                    exception);
                        }
                    }
                }
                finally {
                    producer.close();
                }
            }

        });
        if (this.autoFlush) {
            flush();
        }
        if (this.logger.isTraceEnabled()) {
            this.logger.trace("Sent: " + producerRecord);
        }
        return future;
    }