Capture HTTP metrics of custom http handler

[palaiya]

How do i capture the http metric for this handler:

type appHandler struct {
    *appContext
    H func(*appContext, http.ResponseWriter, *http.Request) (int, error)
}


func (ah appHandler) ServeHTTP(w http.ResponseWriter, r *http.Request) {
    // Updated to pass ah.appContext as a parameter to our handler type.
    status, err := ah.H(ah.appContext, w, r)
    if err != nil {
        log.Printf("HTTP %d: %q", status, err)
        switch status {
        case http.StatusNotFound:
            http.NotFound(w, r)
            // And if we wanted a friendlier error page, we can
            // now leverage our context instance - e.g.
            // err := ah.renderTemplate(w, "http_404.tmpl", nil)
        case http.StatusInternalServerError:
            http.Error(w, http.StatusText(status), status)
        default:
            http.Error(w, http.StatusText(status), status)
        }
    }
}

func main() {
    r := web.New()
    // We pass an instance to our context pointer, and our handler.
    r.Get("/", appHandler{context, IndexHandler})     
    graceful.ListenAndServe(":8086", r)    

}