How to secure access to expvar endpoints with authentication and authorization in Go?

To secure access to expvar endpoints with authentication and authorization in Go, you can follow these steps:

Import the required packages:

import (
    "expvar"
    "net/http"
    "github.com/gorilla/mux"
)

Create a mux.Router to handle the HTTP requests:

router := mux.NewRouter()

Create a http.Handler function to handle the expvar endpoints:

func expvarHandler(w http.ResponseWriter, r *http.Request) {
    // Your code to handle the expvar endpoints
}

Wrap the expvarHandler function with middleware to perform the authentication and authorization checks. Here's an example using basic authentication:

func authenticate(next http.Handler) http.Handler {
    return http.HandlerFunc(func(w http.ResponseWriter, r *http.Request) {
        username, password, _ := r.BasicAuth()
        
        // Your code for authentication, like checking the username and password against a valid user database
        
        // If the user is not authenticated, return a 401 Unauthorized response
        if !authenticated(username, password) {
            w.Header().Set("WWW-Authenticate", `Basic realm="Restricted"`)
            w.WriteHeader(http.StatusUnauthorized)
            return
        }
        
        // If the user is authenticated, call the next middleware or the final handler
        next.ServeHTTP(w, r)
    })
}

Create a http.Handler function that wraps the expvar handler with the authentication middleware:

func securedExpvarHandler(next http.Handler) http.Handler {
    return authenticate(next)
}

router.Handle("/debug/vars", securedExpvarHandler(http.HandlerFunc(expvarHandler)))

Start the HTTP server with the router:

http.ListenAndServe(":8080", router)

With these steps, the access to the expvar endpoints will be secured with authentication and authorization. You can customize the authenticate function to use any other authentication mechanism or authorization checks based on your requirements.