Soul King Streams

Description

Soul King Streams is a Node.js microservice skeleton designed to streamline inter-service communication through Kafka and provide monitoring capabilities via Express.js endpoints. This tool simplifies development, testing, and maintenance processes. The microservice includes two vital API endpoints: /metrics for monitoring metrics and /health for health status checks. It features well-structured classes for handling Kafka messages and an Express.js application setup for monitoring.

Installation

Ensure Node.js and npm are installed on your system. Install Soul King Streams with the following command:

npm i soul-king-streams

Usage

After installation, import the necessary components from Soul King Streams into your Node.js application. The package exports BaseEmitter, BaseListener, KafkaSingleton, and an Express.js application setup (app).

Importing Components

const { BaseEmitter, BaseListener, KafkaSingleton, app } = require('soul-king-streams');

Setting Up KafkaSingleton

Before using BaseEmitter and BaseListener, you must initialize KafkaSingleton with your client ID and Kafka broker addresses.

// Initialize the Kafka client
const clientId = 'my-app-client';
const brokers = ['broker1:9092', 'broker2:9092'];

KafkaSingleton.initialize(clientId, brokers);

// Later in your application, when you need to use Kafka
try {
  const kafka = KafkaSingleton.getInstance();
  // Use the kafka instance for producing or consuming messages
} catch (error) {
  console.error(error.message);
}

API Endpoints

• /metrics: Access monitoring metrics.
• /health: Check the health status of the service.

Kafka Emitter and Listener

Use BaseEmitter and BaseListener for handling Kafka messages, after setting up KafkaSingleton.

BaseEmitter Example:

// You need to initialize the KafkaSingleton first
const { BaseEmitter } = require('soul-king-streams');

// Assuming the Kafka brokers are defined somewhere
const kafkaBrokers = ['broker1:9092', 'broker2:9092'];
const topic = 'my-topic';

// Create an instance of BaseEmitter
const emitter = new BaseEmitter(topic, kafkaBrokers);

// Connect to Kafka
await emitter.connect();

// Emit a message
const message = { key: 'value' }; // Replace with your actual message
await emitter.emit(message);

// Disconnect after done
await emitter.disconnect();

BaseListener Example:

// You need to initialize the KafkaSingleton first
const { BaseListener } = require('soul-king-streams');

class MyKafkaListener extends BaseListener {
  async onMessage(data) {
    // Implement your message handling logic here
    console.log(`Received message on ${data.topic}:`, data.message.value.toString());
    // Add more processing logic as needed
  }
}

const myListener = new MyKafkaListener({
  groupId: 'my-group',
  topic: ['my-topic'. 'my-topic-2'],
  clientId: 'my-client-id',
  kafkaBrokers: ['broker1:9092', 'broker2:9092']
});

// Connect to the Kafka topic
myListener.connect()
  .then(() => console.log('Connected to Kafka topic.'))
  .catch(error => console.error('Failed to connect:', error));

// Remember to gracefully disconnect when your application is closing
process.on('SIGINT', async () => {
  await myListener.disconnect();
  console.log('Disconnected from Kafka.');
});

Express.js Application Setup

The app component configures Express.js for the monitoring endpoints.

const { app } = require('soul-king-streams');

const PORT = 3000

app.listen(PORT, () => {
	console.log(`Server running on ${ PORT }`);
})

Configuration

Configure Kafka brokers, topics, and Express.js settings according to your project's requirements.

Contributing

Contributions are welcome. Please open an issue for major changes and submit pull requests for contributions.

License

GNU Affero General Public License (AGPL)