Golang-logging middleware

In restful services, it is usually necessary to record request information into logs. The following example shows how go implements a simple logging middleware.

Its basic principle is to foo/barpass the business function (in this example) as a parameter to the log function (in this example logging), and then pass the log function as a parameter http.HandleFunc.

package main

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

func logging(f http.HandlerFunc) http.HandlerFunc {
    
    
    return func(w http.ResponseWriter, r *http.Request) {
    
    
        log.Println(r.URL.Path)
        f(w, r)
    }
}

func foo(w http.ResponseWriter, r *http.Request) {
    
    
    fmt.Fprintln(w, "foo")
}

func bar(w http.ResponseWriter, r *http.Request) {
    
    
    fmt.Fprintln(w, "bar")
}

func main() {
    
    
    http.HandleFunc("/foo", logging(foo))
    http.HandleFunc("/bar", logging(bar))

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

Every time you visit http://localhost:8080/fooor http://localhost:8080/bar, the background will record the requested address

2021/02/28 23:56:41 /bar
2021/02/28 23:56:48 /foo