Use an interface for logger

go.mod

@@ -0,0 +1,5 @@
+module github.com/go-martini/martini
+
+go 1.15
+
+require github.com/codegangsta/inject v0.0.0-20150114235600-33e0aa1cb7c0

go.sum

@@ -0,0 +1,2 @@
+github.com/codegangsta/inject v0.0.0-20150114235600-33e0aa1cb7c0 h1:sDMmm+q/3+BukdIpxwO365v/Rbspp2Nt5XntgQRXq8Q=
+github.com/codegangsta/inject v0.0.0-20150114235600-33e0aa1cb7c0/go.mod h1:4Zcjuz89kmFXt9morQgcfYZAYZ5n8WHjt81YYWIwtTM=

logger.go

@@ -1,14 +1,18 @@
 package martini
 
 import (
-	"log"
 	"net/http"
 	"time"
 )
 
+type logger interface {
+	Printf(s string, a ...interface{})
+	Fatalln(args ...interface{})
+}
+
 // Logger returns a middleware handler that logs the request as it goes in and the response as it goes out.
 func Logger() Handler {
-	return func(res http.ResponseWriter, req *http.Request, c Context, log *log.Logger) {
+	return func(res http.ResponseWriter, req *http.Request, c Context, log logger) {
 		start := time.Now()
 
 		addr := req.Header.Get("X-Real-IP")

martini.go

@@ -31,7 +31,7 @@ type Martini struct {
 	inject.Injector
 	handlers []Handler
 	action   Handler
-	logger   *log.Logger
+	logger   logger
 }
 
 // New creates a bare bones Martini instance. Use this method if you want to have full control over the middleware that is used.
@@ -58,7 +58,7 @@ func (m *Martini) Action(handler Handler) {
 }
 
 // Logger sets the logger
-func (m *Martini) Logger(logger *log.Logger) {
+func (m *Martini) Logger(logger logger) {
 	m.logger = logger
 	m.Map(m.logger)
 }
@@ -118,7 +118,6 @@ type ClassicMartini struct {
 func Classic() *ClassicMartini {
 	r := NewRouter()
 	m := New()
-	m.Use(Logger())
 	m.Use(Recovery())
 	m.Use(Static("public"))
 	m.MapTo(r, (*Routes)(nil))

recovery.go

@@ -4,7 +4,6 @@ import (
 	"bytes"
 	"fmt"
 	"io/ioutil"
-	"log"
 	"net/http"
 	"runtime"
 
@@ -113,7 +112,7 @@ func function(pc uintptr) []byte {
 // Recovery returns a middleware that recovers from any panics and writes a 500 if there was one.
 // While Martini is in development mode, Recovery will also output the panic as HTML.
 func Recovery() Handler {
-	return func(c Context, log *log.Logger) {
+	return func(c Context, log logger) {
 		defer func() {
 			if err := recover(); err != nil {
 				stack := stack(3)