How to Implement a Template Cache in Go

Use html/template or text/template with template.Must to parse templates once at startup and store the result in a variable for reuse. This avoids the expensive parsing step on every request.

import (
	"html/template"
	"log"
)

var templates = template.Must(template.ParseFiles("templates/home.html"))

func handler(w http.ResponseWriter, r *http.Request) {
	if err := templates.Execute(w, data); err != nil {
		log.Println(err)
	}
}

For multiple files, use template.ParseGlob or template.ParseFiles with multiple arguments. Store the *template.Template in a package-level variable initialized at startup.

Parsing template files is slow, so you should do it once when your app starts up instead of every time a user visits a page. Think of it like pre-cooking a meal: you do the hard work once, then just serve the ready food quickly whenever someone orders. This keeps your server fast and responsive.