Untitled

package main

import (
    "html/template"
    "io/ioutil"
    "net/http"
)

var tpl *template.Template

func init() {
    tpl = template.Must(template.ParseGlob("templates/*.gohtml"))
}

func main() {
    http.HandleFunc("/", index)
    http.Handle("/favicon.ico", http.NotFoundHandler())
    http.ListenAndServe(":8080", nil)
}

func index(res http.ResponseWriter, req *http.Request) {
    var s string
    if req.Method == http.MethodPost {
        f, _, err := req.FormFile("fails")
        if err != nil {
            http.Error(res, err.Error(), http.StatusInternalServerError)
            return
        }
        defer f.Close()
        bs, err := ioutil.ReadAll(f)
        if err != nil {
            http.Error(res, err.Error(), http.StatusInternalServerError)
            return
        }
        s = string(bs)
    }
    tpl.ExecuteTemplate(res, "index.gohtml", s)
}

=============================================

<!DOCTYPE html>
<html>
<head>
<title>GoLang :P</title>
</head>
<body>
    <form method="Post" enctype="multipart/form-data">
        <input type="file" name="fails">
        <input type="submit">
        <br><br>
        <h3>{{.}}</h3>
    </form>
</body>
</html>