Distributed Application Architecture

• Decentralization: No single point of failure.
• Scalability: Ability to scale horizontally by adding more nodes.
• Interoperability: Different components can work together, often using APIs.
• Fault Tolerance: System's ability to continue operating despite failures.

3.1 Microservices

Microservices architecture breaks down applications into smaller, independent services that communicate over APIs.

3.2 Service-Oriented Architecture (SOA)

SOA is similar to microservices but typically encompasses more extensive business functionalities.

3.3 Event-Driven Architecture

This architecture relies on events to trigger actions and is often implemented using message brokers.

4.1 Step-by-Step Process

            1. Identify the services required by the application.
            2. Define APIs for communication between services.
            3. Choose a communication protocol (e.g., HTTP, gRPC).
            4. Implement each service independently.
            5. Deploy services in a cloud environment or across multiple servers.
            6. Monitor and maintain services for performance and reliability.
        

4.2 Sample Code

Here’s an example of a simple microservice in Node.js:

                const express = require('express');
                const app = express();

                app.get('/api/greet', (req, res) => {
                    res.send('Hello, World!');
                });

                app.listen(3000, () => {
                    console.log('Service running on port 3000');
                });
            

• Use API gateways to manage and secure service communication.
• Implement robust logging and monitoring across all services.
• Utilize containerization (e.g., Docker) for easy deployment and scaling.
• Ensure continuous integration and continuous delivery (CI/CD) practices are in place.