Connect to Aiven for Apache Kafka® with NodeJS

These examples show how to connect to an Aiven for Apache Kafka® service using the node-rdkafka library.

Prerequisites

1. Install node-rdkafka. Make sure that you have OpenSSL set up on your machine.
2. Go to the Overview page of your Aiven for Apache Kafka service and choose how to authenticate.
   • To connect with SSL authentication, in the Connection information section:
     1. If Authentication Method is shown, choose Client Certificate
     2. Next to Access Key, click Download and save the service.key file.
     3. Next to Access Certificate, click Download and save the service.cert file.
     4. Next to CA Certificate, click Download and save the ca.pem file.
   • To connect using SASL authentication:
     1. See Use SASL Authentication with Apache Kafka® to enable SASL.
     2. In the Connection Information section
        1. Select SASL as the Authentication Method
        2. Next to CA Certificate, click Download and save the ca.pem file
        3. Note the Password required for the SASL, we'll need it for authentication

note

The CA Certificate ca.pem file has the same content regardless of the authentication method.

warning

In the below examples, we just pass the name of the certificate files, but in actual use, the full path should be used.

Variables

Variable	Description
HOST	Host name for the connection
USER_NAME	Name of the user for the connection
SSL_PORT	Port number to use for SSL
SASL_PORT	Port number to use for SASL
SASL_PASSWORD	Password required to connect using SASL
SASL_MECHANISM	Supported SASL mechanisms are PLAIN, SCRAM-SHA-256, SCRAM-SHA-512
CONSUMER_GROUP	Consumer group to read the data

Replace the variables above in the code examples below.

Connect a producer

Add the producer.produce() command with the details of the message to produce.

tip

The consumer example expects the messages to be in a topic named demo-topic,

With SSL authentication

const Kafka = require('node-rdkafka');
console.log(Kafka.features); // this should print 'ssl', among other things

const producer = new Kafka.Producer({
    'metadata.broker.list': HOST:SSL_PORT,
    'security.protocol': 'ssl',
    'ssl.key.location': 'service.key',
    'ssl.certificate.location': 'service.cert',
    'ssl.ca.location': 'ca.pem',
    'dr_cb': true
});

producer.connect();

producer.on('ready', () => {
    // produce the messages and disconnect
});

With SASL authentication

If you prefer to authenticate with SASL, the setup looks slightly different.

const Kafka = require('node-rdkafka');
console.log(Kafka.features); // this should print 'sasl_ssl', among other things

const producer = new Kafka.Producer({
    'metadata.broker.list': HOST:SASL_PORT,
    'security.protocol': 'sasl_ssl',
    'sasl.mechanism': SASL_MECHANISM,
    'sasl.username': USER_NAME,
    'sasl.password': SASL_PASSWORD,
    'ssl.ca.location': 'ca.pem',
    'dr_cb': true
});

producer.connect();

producer.on('ready', () => {
  // produce the messages and disconnect
});

Connect a consumer

The consumer will consume new messages sent to the topics listed. To see your consumer in action, run the producer as well, and try using console.log to inspect the message that is received.

With SSL authentication

const Kafka = require('node-rdkafka');

const stream = new Kafka.createReadStream({
    'metadata.broker.list': HOST:SSL_PORT,
    'group.id': CONSUMER_GROUP,
    'security.protocol': 'ssl',
    'ssl.key.location': 'service.key',
    'ssl.certificate.location': 'service.cert',
    'ssl.ca.location': 'ca.pem'
}, {}, {'topics': ['demo-topic']});

stream.on('data', (message) => {
    // process message
});

With SASL authentication

If you prefer to authenticate with SASL, the setup looks slightly different.

const Kafka = require('node-rdkafka');

const stream = new Kafka.createReadStream({
    'metadata.broker.list': HOST:SASL_PORT,
    'group.id': CONSUMER_GROUP,
    'security.protocol': 'sasl_ssl',
    'sasl.mechanism': SASL_MECHANISM,
    'sasl.username': USER_NAME,
    'sasl.password': SASL_PASSWORD,
    'ssl.ca.location': 'ca.pem'
}, {}, {'topics': ['demo-topic']});

stream.on('data', (message) => {
    // process message
});