Add simple requests logger (in style of Apache Common log format).

Fix Gopkg.lock integrity error.

Gopkg.lock

@@ -318,6 +318,7 @@
     "github.com/mediocregopher/radix.v2/redis",
     "github.com/mediocregopher/radix.v2/util",
     "github.com/mono83/slf",
+    "github.com/mono83/slf/params",
     "github.com/mono83/slf/rays",
     "github.com/mono83/slf/recievers/sentry",
     "github.com/mono83/slf/recievers/statsd",

eventsubscribers/logger.go

@@ -2,6 +2,7 @@ package eventsubscribers
 
 import (
 	"net"
+	"net/http"
 	"net/url"
 	"syscall"
 
@@ -17,10 +18,29 @@ type Logger struct {
 }
 
 func (l *Logger) ConfigureWithDispatcher(d dispatcher.EventDispatcher) {
+	d.Subscribe("skinsystem:after_request", l.handleAfterSkinsystemRequest)
+
 	d.Subscribe("mojang_textures:usernames:after_call", l.createMojangTexturesErrorHandler("usernames"))
 	d.Subscribe("mojang_textures:textures:after_call", l.createMojangTexturesErrorHandler("textures"))
 }
 
+func (l *Logger) handleAfterSkinsystemRequest(req *http.Request, statusCode int) {
+	forwardedIp := req.Header.Get("X-Forwarded-For")
+	if forwardedIp == "" {
+		forwardedIp = req.Header.Get("X-Real-Ip")
+	}
+
+	l.Info(
+		":ip - - \":method :path\" :statusCode \":userAgent\" \":forwardedIp\"",
+		wd.StringParam("ip", req.RemoteAddr),
+		wd.StringParam("method", req.Method),
+		wd.StringParam("path", req.URL.Path),
+		wd.IntParam("statusCode", statusCode),
+		wd.StringParam("userAgent", req.UserAgent()),
+		wd.StringParam("forwardedIp", forwardedIp),
+	)
+}
+
 func (l *Logger) createMojangTexturesErrorHandler(provider string) func(identity string, result interface{}, err error) {
 	providerParam := wd.NameParam(provider)
 	return func(identity string, result interface{}, err error) {

http/skinsystem.go

@@ -89,8 +89,10 @@ type Skinsystem struct {
 }
 
 func (ctx *Skinsystem) CreateHandler() *mux.Router {
+	requestEventsMiddleware := CreateRequestEventsMiddleware(ctx.Emitter, "skinsystem")
+
 	router := mux.NewRouter().StrictSlash(true)
-	router.Use(CreateRequestEventsMiddleware(ctx.Emitter, "skinsystem"))
+	router.Use(requestEventsMiddleware)
 
 	router.HandleFunc("/skins/{username}", ctx.Skin).Methods(http.MethodGet)
 	router.HandleFunc("/cloaks/{username}", ctx.Cape).Methods(http.MethodGet).Name("cloaks")
@@ -106,7 +108,9 @@ func (ctx *Skinsystem) CreateHandler() *mux.Router {
 	apiRouter.HandleFunc("/skins/id:{id:[0-9]+}", ctx.DeleteSkinByUserId).Methods(http.MethodDelete)
 	apiRouter.HandleFunc("/skins/{username}", ctx.DeleteSkinByUsername).Methods(http.MethodDelete)
 	// 404
-	router.NotFoundHandler = http.HandlerFunc(NotFound)
+	// NotFoundHandler doesn't call for registered middlewares, so we must wrap it manually.
+	// See https://github.com/gorilla/mux/issues/416#issuecomment-600079279
+	router.NotFoundHandler = requestEventsMiddleware(http.HandlerFunc(NotFound))
 
 	return router
 }