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How to use Kafka in NodeJs

December 24, 2019

  1. Create a folder KafkaNodeJs
  2. Run npm init command from inside the folder and answer the few question like author, license, etc… once done, package.json file will be created in our folder.
  3. create a new file index.js

we will use kafkajs library.

  1. open command prompt and run npm install kafkajs
  2. open index.js file and type below program
const { Kafka, PartitionAssigners: { roundRobin } } = require("kafkajs");

const kafka = new Kafka({
  clientId: 'my-app',
  brokers: ["localhost:9092"]
});

const consumer = kafka.consumer({ groupId: "test-consumer-group-1", partitionAssigners: [roundRobin] });

const run = async () => {
  // Consuming
  await consumer.connect();
  await consumer.subscribe({ topic: "testTopic", fromBeginning: false });

  await consumer.run({
    eachMessage: async ({ topic, partition, message }) => {
      console.log(message.value.toString() + " - from Partition " + partition);
    }
  });
};

run().catch(console.error);

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