Apache Kafka is a popular distributed event streaming platform used for high-performance data pipelines, real-time analytics, and event-driven applications.

Step 1: First things first, you need to get Apache Kafka installed on your machine. Head over to its official page and download it. The installation steps will differ depending on your operating system.

Step 2: Once you've got Kafka installed, you'll need to start a Zookeeper service. Kafka relies on Zookeeper to manage and coordinate Kafka brokers. Run this command to get Zookeeper up and running:

bin/zookeeper-server-start.sh config/zookeeper.properties

Step 3: Now, it's time to start the Kafka server. Use this command to fire up a Kafka broker:

bin/kafka-server-start.sh config/server.properties

Supabase is an open-source alternative to Firebase that lets you develop faster with less effort.

Step 1: First, you need to install the Supabase CLI. You can do this globally with npm:

npm install -g @supabase/cli

Step 2: Next, initialize a new Supabase project:

supabase init

This will create a Supabase project structure with a docker-compose file.

Step 3: Finally, you need to start the Supabase service:

supabase start

This will kick off all the underlying services required for Supabase in Docker, and spin up a localhost environment.

Step 1: First, you need to create a Kafka topic where the real-time changes from Supabase can be sent. Use this command to create a Kafka topic, replacing test with your topic name:

bin/kafka-topics.sh --create --topic test --bootstrap-server localhost:9092

Step 2: Next, you need to listen for changes in the Supabase database. Supabase provides a real-time client that you can use to subscribe to changes. The changes can then be sent to the Kafka topic. Here's an example of how to do it in Node.js:

// Initialize Supabase Realtime client
const { RealtimeClient } = require('@supabase/realtime-js')

// Initialize KafkaJS client
const { Kafka } = require('kafkajs')

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

const producer = kafka.producer()

const client = new RealtimeClient('ws://localhost:8000/socket', { params: { apikey: 'supabasekey' } })
client.connect()

client.on('INSERT', 'public.posts', async (payload) => {
  await producer.send({
    topic: 'test',
    messages: [{ value: JSON.stringify(payload) }],
  })
})

This code will listen for INSERT operations on the public.posts table in Supabase and send the changes to the Kafka topic test.

Step 3: To process the streamed data in Kafka, you need to write a Kafka consumer. Here's how you do it with KafkaJS:

const consumer = kafka.consumer({ groupId: 'test-group' })

await consumer.connect()
await consumer.subscribe({ topic: 'test', fromBeginning: true })

await consumer.run({
  eachMessage: async ({ topic, partition, message }) => {
    console.log({
      value: message.value.toString(),
    })
  },
})

The consumer will log all messages it receives from the Kafka topic test.

Please note that to get this to work, you must replace 'ws://localhost:8000/socket' and 'supabasekey' in the example with the actual WebSocket URL and the corresponding API key of your Supabase instance. Similarly, replace 'kafka:9092' with the actual address to your Kafka broker.