Connect to your cluster using the Kafka Node.js client

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Before you begin

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Steps

1. Install the Kafka Nodejs client.
   npm install kafkajs
   
2. Build a Nodejs application to produce and consume messages.
   const { Kafka } = require('kafkajs')
   
   // Step 1: replace with your configurations
   let serverUrl = 'SERVER-URL'
   let jwtToken = 'API-KEY'
   let topicName = 'test-js-topic'
   let namespace = 'public/default'
   
   // Step 2: create the kafka client
   const kafka = new Kafka({
     clientId: 'my-app',
     brokers: [serverUrl],
     ssl: true,
     sasl: {
       mechanism: 'plain',
       username: namespace,
       password: 'token:' + jwtToken,
     },
   })
   
   // Step 3: send a message to your topic
   async function send() {
     const producer = kafka.producer()
     await producer.connect()
   
     let resp = await producer.send({
       topic: topicName,
       messages: [
         {
           value: 'Hello KafkaJS user!',
         },
       ],
     })
   
     console.log(`Send message:`, resp)
   
     await producer.disconnect()
   }
   
   // Step 4: read messages from the beginning of your topic
   async function receive() {
     const consumer = kafka.consumer({
       groupId: 'my-group',
       readUncommitted: true, // Note: Ursa does not support read_committed for now
     })
     await consumer.connect()
     console.log('Connected to Kafka')
   
     await consumer.subscribe({ topic: topicName, fromBeginning: true })
   
     await consumer.run({
       eachMessage: async ({ topic, partition, message }) => {
         console.log(`Received message:`, {
           value: message.value.toString(),
           headers: message.headers,
           topic: topic,
           partition: partition,
           offset: message.offset,
         })
       },
     })
   }
   
   // Step 5: send one message then receive
   send().then(function () {
     receive()
   })
   
   • SERVER-URL: the Kafka service URL of your StreamNative cluster.
   • API-KEY: an API key of your service account.
3. Run the Node.js application with your saved scripts. This example runs the Node.js application assuming that you save the scripts as kop_test.js.
   node kop_test.js
   
   You should see the following output:
   Send message: [
     {
       topicName: 'test-js-topic',
       partition: 0,
       errorCode: 0,
       baseOffset: '7',
       logAppendTime: '-1',
       logStartOffset: '-1'
     }
   ]
   Connected to Kafka
   Received message: {
     value: 'Hello KafkaJS user!',
     headers: {},
     topic: 'test-js-topic',
     partition: 0,
     offset: '0'
   }
   ...