Simple Load Balancer

This Go package implements a simple load balancer with round-robin server selection and basic health checks.

Features

• Round-robin load balancing
• Health checks for backend servers
• Reverse proxy to forward requests to backend servers

Installation

• Ensure you have Go installed on your system. You can download it from golang.org.
• Clone the repository or download the source code.

git clone https://github.com/arnab-afk/loadbalancer.git
cd loadbalancer

Run

go run .

Configuration

To customize the server list or the port, modify the main function in main.go:

func main() {
    serverList := []Server{
        newSimpleServer("https://www.facebook.com/"),
        newSimpleServer("https://www.bing.com/"),
        newSimpleServer("https://www.duckduckgo.com/"),
    }

    lb := newLoadBalancer("8009", serverList)
    handleRedirect := func(rw http.ResponseWriter, req *http.Request) {
        lb.serveProxy(rw, req)
    }
    http.HandleFunc("/", handleRedirect)
    fmt.Printf("Load Balancer started at :%s\n", lb.port)
    err := http.ListenAndServe(":"+lb.port, nil)
    handleError(err)
}

Code Overview

simpleServer This type represents a backend server.

• Address() string: Returns the server address.
• IsAlive() bool: Checks if the server is alive by sending an HTTP GET request and checking the response status.
• Serve(rw http.ResponseWriter, req *http.Request): Forwards the request to the backend server using a reverse proxy.

---

LoadBalancer This type represents the load balancer.

• getNextAvailableServer() Server: Implements the round-robin algorithm to select the next available server.
• serveProxy(rw http.ResponseWriter, req *http.Request): Forwards the request to the selected backend server.

---

Example

Here is an example of how the load balancer works:

func main() {
    serverList := []Server{
        newSimpleServer("https://www.facebook.com/"),
        newSimpleServer("https://www.bing.com/"),
        newSimpleServer("https://www.duckduckgo.com/"),
    }

    lb := newLoadBalancer("8009", serverList)
    handleRedirect := func(rw http.ResponseWriter, req *http.Request) {
        lb.serveProxy(rw, req)
    }
    http.HandleFunc("/", handleRedirect)
    fmt.Printf("Load Balancer started at :%s\n", lb.port)
    err := http.ListenAndServe(":"+lb.port, nil)
    handleError(err)
}

In this example, the load balancer will start on port 8009 and forward incoming requests to one of the servers in the list (https://www.facebook.com/, https://www.bing.com/, https://www.duckduckgo.com/) using a round-robin algorithm. If a server is not alive, it will be skipped, and the next available server will be selected.

Contributing

Contributions are welcome! Please feel free to submit a Pull Request.