Go Load Balancer

Overview

This project implements a simple round-robin load balancer in Go. It distributes incoming HTTP requests across multiple backend servers, handles server health checks, and simulates server downtime for testing purposes.

Features

• Round-robin load balancing
• Dynamic health checking of backend servers
• Graceful handling of server downtime
• Simulation of random server outages for testing
• Concurrent operation using goroutines

Prerequisites

• Go 1.15 or higher

Installation

1. Clone the repository:

   git clone https://github.com/yourusername/go-load-balancer.git
   cd go-load-balancer
   

2. Build the project:

   go build -o load-balancer
   

Usage

1. Start the load balancer:

   ./load-balancer
   

2. The load balancer will start on port 8080, and four backend servers will be started on ports 8081, 8082, 8083, and 8084.

3. Send requests to the load balancer:

   curl http://localhost:8080
   

4. Observe the console output to see how requests are distributed and how the system handles simulated server downtime.

Configuration

The main configuration is done in the main() function:

• Backend servers are defined in the servers slice.
• Health check interval is set to 5 seconds.
• Server downtime simulation occurs every 60 seconds and lasts for 60 seconds.

You can modify these values to suit your testing needs.

Project Structure

• main.go: Contains the entire implementation of the load balancer.
  • Server struct: Represents a backend server.
  • RoundRobinServerPool struct: Manages the pool of servers and implements the load balancing logic.
  • LoadBalancer function: Handles incoming requests and forwards them to the next available server.
  • simulateServerDowntime function: Simulates random server outages.

How It Works

1. The load balancer initializes a pool of backend servers.
2. It starts each backend server and begins health checks.
3. When a request comes in, the load balancer selects the next healthy server in a round-robin fashion.
4. If a server is down, it's skipped, and the next healthy server is selected.
5. Periodically, the simulateServerDowntime function will randomly stop a server and restart it after a delay.

Testing

To test the load balancer:

1. Start the load balancer.
2. Send multiple requests to http://localhost:8080.
3. Observe the console output to see how requests are distributed.
4. Wait for the downtime simulation to occur and observe how the system handles server outages.

Limitations and Future Improvements

• The current implementation uses a simple round-robin algorithm. More sophisticated algorithms could be implemented.
• The project could benefit from more comprehensive logging and metrics.
• Configuration is currently hardcoded. Adding a configuration file or command-line flags would improve flexibility.