org.apache.gobblin.metrics.kafka.KafkaPusher.java Source code

Introduction

Here is the source code for org.apache.gobblin.metrics.kafka.KafkaPusher.java

Source

/*
 * 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.gobblin.metrics.kafka;

import java.io.IOException;
import java.util.List;
import java.util.Properties;

import com.google.common.base.Function;
import com.google.common.collect.Lists;
import com.google.common.io.Closer;

import javax.annotation.Nullable;
import kafka.producer.KeyedMessage;
import kafka.producer.ProducerConfig;

/**
 * Establishes a connection to a Kafka cluster and pushed byte messages to a specified topic.
 */
public class KafkaPusher implements Pusher<byte[]> {

    private final String topic;
    private final ProducerCloseable<String, byte[]> producer;
    private final Closer closer;

    public KafkaPusher(String brokers, String topic) {
        this.closer = Closer.create();

        this.topic = topic;

        Properties props = new Properties();
        props.put("metadata.broker.list", brokers);
        props.put("serializer.class", "kafka.serializer.DefaultEncoder");
        props.put("request.required.acks", "1");

        ProducerConfig config = new ProducerConfig(props);
        this.producer = createProducer(config);
    }

    /**
     * Push all mbyte array messages to the Kafka topic.
     * @param messages List of byte array messages to push to Kakfa.
     */
    public void pushMessages(List<byte[]> messages) {
        List<KeyedMessage<String, byte[]>> keyedMessages = Lists.transform(messages,
                new Function<byte[], KeyedMessage<String, byte[]>>() {
                    @Nullable
                    @Override
                    public KeyedMessage<String, byte[]> apply(byte[] bytes) {
                        return new KeyedMessage<String, byte[]>(topic, bytes);
                    }
                });
        this.producer.send(keyedMessages);
    }

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

    /**
     * Actually creates the Kafka producer.
     */
    protected ProducerCloseable<String, byte[]> createProducer(ProducerConfig config) {
        return this.closer.register(new ProducerCloseable<String, byte[]>(config));
    }
}