certserver.go

package main

import (
	"fmt"
	"net/http"
	"os"
	"strings"
)

func main() {
	challenge := os.Args[1]
	fileName := strings.Split(challenge, ".")[0]

	route := fmt.Sprintf("/.well-known/acme-challenge/%v", fileName)
	fmt.Println(route)

	http.HandleFunc(route, func(w http.ResponseWriter, r *http.Request) {
		w.Write([]byte(challenge))
	})

	if err := http.ListenAndServe(":80", nil); err != nil {
		panic(err)
	}
}