如何使用kafka-node从主题读取数据?

问题描述

我有一个必须从kafka服务器读取的主题，因此，我只需要创建可以从kafka主题读取数据的使用者，我总是会得到错误主题.

I have topic that i have to read from kafka server so for that i just need to create consumer that can read data from kafka topic, I always get error topic does not exist.

1-如何确定kafka连接已建立?

1- How can i make sure kafka connection is established ?

2-如何从kafka中的特定主题获取数据?

2- How to get the data from specific topic in kafka ?

main.js

var kafka = require('kafka-node');
var config = require('./config.js');
var kafkaConn = config.kafkaCon.dit;
var HighLevelConsumer = kafka.HighLevelConsumer;
//var HighLevelProducer = kafka.HighLevelProducer;
var Client = kafka.Client;
var Offset = kafka.Offset;
var topics = [{topic: 'UEQ'}];
var client = new Client(kafkaConn);
var payloads = [ { topic: topics, partition : 0}];
var options = {
    groupId: 'kafka-node-group',
// Auto commit config
    autoCommit: true,
    autoCommitMsgCount: 100,
    autoCommitIntervalMs: 5000,
// Fetch message config
    fetchMaxWaitMs: 100,
    fetchMinBytes: 1,
    fetchMaxBytes: 1024 * 10,
};
var consumer = new HighLevelConsumer(client, payloads, options);

consumer.on('message', function (message) {
    console.log('TEST',this.id, message);
});

错误

events.js:141
      throw er; // Unhandled 'error' event
      ^
 TopicsNotExistError: The topic(s) [object Object] do not exist
    at new TopicsNotExistError (C:\uilogging\node_modules\kafka-node\lib\errors\
TopicsNotExistError.js:11:11)

推荐答案

我正在做一个类似的项目，其中我在自己的服务器上有一个Kafka生产者，并且正在使用Kafka-Node作为我的应用程序的使用者.我对Kafka-Node相当陌生，并且没有太多经验，但是我可以尝试分享一些我发现的见解.

I am doing a similar project where i have a Kafka producer on its own server and am using Kafka-Node as a consumer for my application. I am fairly new to Kafka-Node, and don't have much experience with it, but i can try to share some of the insights i have found.

我相信您的问题实际上是您的主题不存在.

I believe your problem is literally that your topic doesn't exist.

如果您的连接没有建立，我认为它不会继续说该主题不存在.当我键入一个不存在的主题并且为我的Kafka生产者键入一个随机IP时，没有任何错误.但是，当我指向正确的ip，并且仍然有不正确的主题时，就会收到与您看到的相同的错误.

If your connection wasn't established, i don't think it would move on to say the topic doesn't exist. When i type in a topic that doesn't exist and i type a random ip for my Kafka producer, nothing errors out. But when i point to the correct ip, and an still have incorrect topic, i get the same error you see.

var kafka = require('kafka-node');
var Consumer = kafka.Consumer,
    // The client specifies the ip of the Kafka producer and uses
    // the zookeeper port 2181
    client = new kafka.Client("<ip to producer>:2181"),
    // The consumer object specifies the client and topic(s) it subscribes to
    consumer = new Consumer(
        client, [ { topic: 'myTopic', partition: 0 } ], { autoCommit: false });

consumer.on('message', function (message) {
    // grab the main content from the Kafka message
    var data = JSON.parse(message.value);
    console.log(data);
});

希望这不会太晚.

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