Using "gorilla/sessions"

main.go

package main

import (
	"net/http"

	"github.com/gorilla/mux"
	"github.com/gorilla/sessions"
)

func main() {
	store := sessions.NewCookieStore([]byte("something-very-secret"))

	r := mux.NewRouter()
	r.HandleFunc("/set", func(w http.ResponseWriter, r *http.Request) {
		session, _ := store.Get(r, "session-name")
		session.Values["myvalue"] = r.FormValue("myvalue")
		store.Save(r, w, session)
	})
	r.HandleFunc("/get", func(w http.ResponseWriter, r *http.Request) {
		session, _ := store.Get(r, "session-name")
		w.Write([]byte(session.Values["myvalue"].(string)))
	})

	http.ListenAndServe(":8080", r)
}

func catch(err error) {
	if err != nil {
		panic(err)
	}
}