func main() {
    http.HandleFunc("/api", apiHandler)
    http.HandleFunc("/query/main", mainHandler)
    http.HandleFunc("/query/show", showHandler)
    http.HandleFunc("/", mainHandler)
    http.ListenAndServe(":8081", nil)
}

func callCurl(postData string) (result string, err error) {
    easy := curl.EasyInit()
    defer easy.Cleanup()
    easy.Setopt(curl.OPT_URL, "http://localhost:8540")
    easy.Setopt(curl.OPT_POST, true)
    easy.Setopt(curl.OPT_VERBOSE, true)
    easy.Setopt(curl.OPT_HTTPHEADER, []string{"Content-Type: application/json"})
    easy.Setopt(curl.OPT_POSTFIELDSIZE, len(postData))
    easy.Setopt(curl.OPT_READFUNCTION, func(ptr []byte, _ interface{}) int {
        return copy(ptr, postData)
    })
    easy.Setopt(curl.OPT_WRITEFUNCTION, func(buf []byte, _ interface{}) bool {
        result = string(buf)
        return true
    })
    if err := easy.Perform(); err != nil {
        return "", err
    }
    return result, nil
}

opt := &pretty.Options{Width: 80, Prefix: "<br>", Indent: "&nbsp;&nbsp;&nbsp;&nbsp;", SortKeys: false}
result = string(pretty.PrettyOptions([]byte(result), opt)

worker_processes  5;
worker_rlimit_nofile 8192;
events {
  worker_connections  4096;
}
http {
    upstream myapp1 {
        server server1:8081;
        server server2:8081;
    }
    server {
        listen 8080;
        location / {
            proxy_pass http://myapp1;
        }
    }
}