package main

import (
	"log"
	"net/http"
	"net/http/httputil"
	"net/url"
	"os"
	"strconv"
)

func main() {

	proxy := os.Getenv("PE_PROXY")
	if proxy == "" {
		log.Fatal("PE_PROXY not specified")
		return
	}
	proxyUrl, err := url.Parse(proxy)
	if err != nil {
		log.Fatal(err.Error())
		return
	}

	upstream := os.Getenv("PE_UPSTREAM")
	if upstream == "" {
		log.Fatal("PE_UPSTREAM not specified")
		return
	}
	upstreamUrl, err := url.Parse(upstream)
	if err != nil {
		log.Fatal(err.Error())
		return
	}

	portString := os.Getenv("PE_PORT")
	if portString == "" {
		log.Fatal("PE_PORT not specified")
		return
	}

	port, err := strconv.Atoi(portString)
	if err != nil {
		log.Fatal(err.Error())
		return
	}

	rp := httputil.NewSingleHostReverseProxy(upstreamUrl)
	rp.Transport = &http.Transport{
		Proxy:             http.ProxyURL(proxyUrl),
		DisableKeepAlives: true,
	}

	err = http.ListenAndServe("0.0.0.0:"+strconv.Itoa(port), http.HandlerFunc(func(rw http.ResponseWriter, r *http.Request) {
		log.Printf("%s %s %s\n", r.RemoteAddr, r.Method, r.URL.String())
		rp.ServeHTTP(rw, r)
	}))
	if err != nil {
		log.Fatal(err.Error())
		return
	}

}