Question

我正在使用node-rdkafka使用node express开发Node JS。对于Kafka连接，我使用了Stream API。

我最初在两个不同的端点上设置了生产者和消费者。

对于生产者（kafkaRouter）：

var express = require('express');
var router = express.Router();
var Kafka = require('node-rdkafka')

/* GET users listing. */
router.get('/', produceMessage);

// Our producer with its Kafka brokers
// This call returns a new writable stream to our topic 'topic-name'
var stream = Kafka.Producer.createWriteStream({
  'metadata.broker.list': 'localhost:9092',
          'dr_cb': true
}, {}, {
  topic: 'test'
});

function produceMessage(req,res){

    var queuedSuccess = stream.write(Buffer.from('Hey there!'));

  if (queuedSuccess) {
    console.log('We queued our message!');
  } else {
    // Note that this only tells us if the stream's queue is full,
    // it does NOT tell us if the message got   to Kafka!  See below...
    console.log('Too many messages in our queue already');
  }

  // NOTE: MAKE SURE TO LISTEN TO THIS IF YOU WANT THE STREAM TO BE DURABLE
  // Otherwise, any error will bubble up as an uncaught exception.
  stream.on('error', function (err) {
    // Here's where we'll know if something went wrong sending to Kafka
    console.error('Error in our kafka stream');
    console.error(err);
  })
     
    return res.send("Hello Kafka!")
    
  }
    

module.exports = router;

对于消费者，我将函数放在索引（indexRouter）中：

var express = require('express');
var router = express.Router();
var { KafkaConsumer } = require('node-rdkafka');

/* GET home page. */
router.get('/', getMessage);


const globalConfig = {
  'client.id': 'kafka-mocha',
  'group.id': 'kafka-mocha-grp',
  'metadata.broker.list': 'localhost:9092'
};


var stream = KafkaConsumer.createReadStream(globalConfig, {}, {
  topics: ['test']
});

function getMessage(req,res){
  var result = '';
  stream.on('data', function(message) {
      console.log('Got message');
      console.log(message.value.toString());
      result = result + ' ' + message.value.toString()
  });
  stream.consumer.commit();
  return res.send("Express Router");
  
}
module.exports = router;

然后我将它们添加到app.js

var express = require('express');
var app = express();

app.use('/', indexRouter);
app.use('/kafka', kafkaRouter);

我在这种方法上注意到的是，我只需要调用一次indexRouter，并且使用者将连续监听Queue，并且每次生产者推送一条消息时。尽管工作正常，但如果只需要调用一次，则将使用者放在路由器上是很尴尬的。所以我想我可以像这样直接将其放在app.js中：

const run = async () => {
  const globalConfig = {
    'client.id': 'kafka-mocha',
    'group.id': 'kafka-mocha-grp',
    'metadata.broker.list': 'localhost:9092'
  };


  var stream = KafkaConsumer.createReadStream(globalConfig, {}, {
    topics: ['test']
  });

  var result = '';
  stream.on('data', function(message) {
      console.log('Got message');
      console.log(message.value.toString());
      result = result + ' ' + message.value.toString()
  });
  stream.consumer.commit();
}
run().catch(e => console.error(e));

我还尝试将其封装在静态方法中，然后调用。两种方法都给了我这个错误：

node-kafka-test@0.0.0 start /Users/workspace/node-kafka-test
> node ./bin/www

Error: KafkaConsumer is disconnected
    at KafkaConsumer.commit

初始化使用者时，node-rdkafka KafkaConsumer断开连接

0 个答案: