a simple http-proxy program use goproxy, with basic auth

rainy-proxy.go

package main

import (
	"log"
	"net/http"

	"github.com/elazarl/goproxy"
	"github.com/elazarl/goproxy/ext/auth"
)

func main() {
	proxy := goproxy.NewProxyHttpServer()
	proxy.Verbose = true
	proxy.OnRequest().HandleConnect(auth.BasicConnect("rainy-proxy v0.0.1", func(user, passwd string) bool {
		return user == "rainy" && passwd == "proxy"
	}))
	log.Fatal(http.ListenAndServe(":8000", proxy))
}

You should be using the ProxyBasic function instead of BasicConnect.