Streaming

In this section, we will show how to integrate your application with Kafka streaming.

Consuming topics

To consume Kafka topics, you first need to write an events/<topic>.ts file that is the topic event handler function.

For example, to consume events from a hello topic, create a events/hello.ts file with the following contents:

my-backend/events/hello.ts

import { ChiselEvent } from "@chiselstrike/api";

function toJSON(buffer: ArrayBuffer) {
    return JSON.parse(String.fromCharCode.apply(null, new Uint8Array(buffer)));
}

export default async function (event: ChiselEvent) {
    console.log(toJSON(event.value));
}

Then, pass the --kafka-connection <host> and --kafka-topics <topic> command line options to the ChiselStrike server.

For example, if your Kafka broker is running on localhost:9092 and you want to subscribe to the hello topic, run:

npm run dev -- -- --kafka-connection localhost:9092 --kafka-topics hello

That's it! Now whenever there is an event on the hello topic, your event handler function is called.