Node.js 操作kafka

基础知识可参考：douzixiansheng/MQ​github.com/douzixiansheng/MQ/blob/master/kafka_basic.md

1.准备好kafka环境，没有安装的伙伴可以参考 （讲解了linux如何安装kafka）：

douzixiansheng/MQ​github.com/douzixiansheng/MQ/blob/master/kafka_linux_install.md

2. 安装依赖 kafka-node 模块,编写package.json

{
    "name": "kafka",
    "private": false,
    "dependencies": {
        "kafka-node": "4.1.3"
    },
    "devDependencies": {
        "mocha": ">=0.0.1"
    }
}

3. 编写生产者与消费者 具体api可以参考官网：

kafka-node​www.npmjs.com/package/kafka-node

生产者：

/**
 * 生产者
 */

const kafka = require('kafka-node');

let conn = {'kafkaHost':'127.0.0.1:9092'};

var MQ = function (){
    this.mq_producers = {};
}

MQ.prototype.AddProducer = function (conn, handler){
    console.log('增加生产者',conn, this);
    let client = new kafka.KafkaClient(conn);
    let producer = new kafka.Producer(client);

    producer.on('ready', function(){
        if(!!handler){
            handler(producer);
        }
    });

    producer.on('error', function(err){
        console.error('producer error ',err.stack);
    });

    this.mq_producers['common'] = producer;
    return producer;
}
console.log(MQ);
var mq = new MQ();

mq.AddProducer(conn, function (producer){
    producer.createTopics(['broadcast'], function (){
        setInterval(function(){
            mq.mq_producers['common'].send([{topic:['broadcast'], 
            messages:[JSON.stringify({"cmd":"testRpc","value":"Hello World"})]}], function (){
                console.log("..... ");
            })
        }, 2000);
    })
});

消费者：

/**
 * 消费者
 */

const kafka = require('kafka-node');

let conn = {'kafkaHost':'127.0.0.1:9092'};
let consumers = [
    {
        'type': 'consumer',
        'options': {'autoCommit': true},
        'name':'common',
        'topic':[
            {'topic': 'broadcast', 'partition': 0}
        ]
    }
];

let MQ = function(){

}

MQ.prototype.AddConsumer = function (conn, topics, options, handler){
    let client = new kafka.KafkaClient(conn);
    let consumer = new kafka.Consumer(client, topics, options);

    if(!!handler){
        consumer.on('message', handler);
    }

    consumer.on('error', function(err){
        console.error('consumer error ',err.stack);
    });
}

var mq = new MQ();


mq.AddConsumer(conn, consumers[0].topic, consumers[0].options, function (message){
    console.log(message.value);
});

4.执行生产者脚本

root@FM:/home/MQ/Kafka# node producer.js 
[Function: MQ]
增加生产者 { kafkaHost: '127.0.0.1:9092' } MQ { mq_producers: {} }
..... 
..... 
..... 
..... 
..... 
..... 
..... 
..... 
..... 
..... 
..... 

执行消费者脚本

root@FM:/home/MQ/Kafka# node consumer.js 
{"cmd":"testRpc","value":"Hello World"}
{"cmd":"testRpc","value":"Hello World"}
{"cmd":"testRpc","value":"Hello World"}
{"cmd":"testRpc","value":"Hello World"}
{"cmd":"testRpc","value":"Hello World"}
{"cmd":"testRpc","value":"Hello World"}
{"cmd":"testRpc","value":"Hello World"}
{"cmd":"testRpc","value":"Hello World"}

可以看到每隔两秒生产者往主题topic(broadcast) 上生产消息，消费者从主题上拉取消息