Go: Get path parameters from http.Request

I'm developing a REST API with Go, but I don't know how can I do the path mappings and retrieve the path parameters from them.

I want something like this:

func main() {
    http.HandleFunc("/provisions/:id", Provisions) //<-- How can I map "id" parameter in the path?
    http.ListenAndServe(":8080", nil)
}

func Provisions(w http.ResponseWriter, r *http.Request) {
    //I want to retrieve here "id" parameter from request
}

I would like to use just http package instead of web frameworks, if it is possible.

Thanks.

If you are using Go 1.22, you can easily retrieve the path parameters with r.PathValue(). For example:

package main

import (
    "fmt"
    "net/http"
    "net/http/httptest"
)

func main() {
    mux := http.NewServeMux()
    mux.HandleFunc("/provisions/{id}", func(w http.ResponseWriter, r *http.Request) {
        fmt.Println("Provision ID: ", r.PathValue("id"))
    })

    mux.ServeHTTP(httptest.NewRecorder(), httptest.NewRequest("GET", "/provisions/123", nil))
    mux.ServeHTTP(httptest.NewRecorder(), httptest.NewRequest("GET", "/provisions/456", nil))
}

Demo in Go Playground. Source: https://pkg.go.dev/net/http#Request.PathValue