Simple Reverse Proxy Program in Go

Go offers a lot of functionality with networking out of the box. A reverse proxy in Go can be implemented using the net/http package, which provides a solid foundation for creating HTTP servers and clients. Here is a simple program to help proxy requests to a hard coded upstream server.

package main

import (
    "fmt"
    "net/http"
    "net/http/httputil"
    "net/url"
)

// Define a struct to hold the reverse proxy configuration
type ProxyConfig struct {
    Target *url.URL
}

// ReverseProxyHandler creates a new reverse proxy handler
func ReverseProxyHandler(target *url.URL) http.Handler {
    return httputil.NewSingleHostReverseProxy(target)
}

func main() {
    // Define the target URL of the upstream server
    targetURL := "http://localhost:8081"
    target, err := url.Parse(targetURL)
    if err != nil {
        fmt.Println("Error parsing target URL:", err)
        return
    }

    // Create a new reverse proxy instance
    proxy := ReverseProxyHandler(target)

    // Create a new HTTP server
    server := &http.Server{
        Addr:    ":80", // Port to listen on
        Handler: proxy,
    }

    fmt.Println("Reverse proxy server is listening on port 8080...")
    
    // Start the HTTP server
    err = server.ListenAndServe()
    if err != nil {
        fmt.Println("Error starting server:", err)
    }
}