Confluent's JavaScript Client for Schema RegistryTM

Confluent's JavaScript client for Schema Registry supports Avro, Protobuf and JSON Schema, and is designed to work with Confluent's JavaScript Client for Apache Kafka. The goal is to provide a highly performant, reliable and easy to use JavaScript client in line with other Schema Registry clients such as our Go, .NET, and Java clients.

Installation

npm install @confluentinc/schemaregistry

Getting Started

Below is a simple example of using Avro serialization with the Schema Registry client and the KafkaJS client.

const { Kafka } = require('@confluentinc/kafka-javascript').KafkaJS;
const { SchemaRegistryClient, SerdeType, AvroSerializer, AvroDeserializer} = require('@confluentinc/schemaregistry');

const registry = new SchemaRegistryClient({ baseURLs: ['http://localhost:8081'] })
const kafka = new Kafka({
  kafkaJS: {
    brokers: ['localhost:9092']
  }
});

let consumer = kafka.consumer({
  kafkaJS: {
    groupId: "test-group",
    fromBeginning: true,
  },
});
let producer = kafka.producer();

const schema = {
  type: 'record',
  namespace: 'examples',
  name: 'RandomTest',
  fields: [
    { name: 'fullName', type: 'string' }
  ],
};

const topicName = 'test-topic';
const subjectName = topicName + '-value';

const run = async () => {
  // Register schema
  const id = await registry.register(
    subjectName,
    {
      schemaType: 'AVRO',
      schema: JSON.stringify(schema)
    }
  )

  // Create an Avro serializer
  const ser = new AvroSerializer(registry, SerdeType.VALUE, { useLatestVersion: true });

  // Produce a message with the schema
  await producer.connect()
  const outgoingMessage = {
    key: 'key',
    value: await ser.serialize(topicName, { fullName: 'John Doe' }),
  }
  await producer.send({
    topic: topicName,
    messages: [outgoingMessage]
  });
  console.log("Producer sent its message.")
  await producer.disconnect();
  producer = null;

  // Create an Avro deserializer
  const deser = new AvroDeserializer(registry, SerdeType.VALUE, {});

  await consumer.connect()
  await consumer.subscribe({ topic: topicName })

  let messageRcvd = false;
  await consumer.run({
    eachMessage: async ({ message }) => {
      const decodedMessage = {
        ...message,
        value: await deser.deserialize(topicName, message.value)
      };
      console.log("Consumer received message.\nBefore decoding: " + JSON.stringify(message) + "\nAfter decoding: " + JSON.stringify(decodedMessage));
      messageRcvd = true;
    },
  });

  // Wait around until we get a message, and then disconnect.
  while (!messageRcvd) {
    await new Promise((resolve) => setTimeout(resolve, 100));
  }

  await consumer.disconnect();
  consumer = null;
}

run().catch (async e => {
  console.error(e);
  consumer && await consumer.disconnect();
  producer && await producer.disconnect();
  process.exit(1);
})

Features and Limitations

• Avro, Protobuf, and JSON Schema support
• Support for CSFLE (Client-Side Field Level Encryption)
• Support for data quality rules
• Support for schema migration rules for Avro and JSON Schema
• Support for OAuth

Contributing

Bug reports and feedback is appreciated in the form of Github Issues. For guidelines on contributing please see CONTRIBUTING.md