add middleware stack

src/cmd/frontend/main.go

@@ -19,10 +19,15 @@ func main() {
 	// define app
 	webapp := app.NewApp(db)
 
+	// create middle
+	stack := middleware.CreateStack(
+		middleware.Logging,
+	)
+
 	// start web server
 	server := http.Server{
 		Addr:    ":8080",
-		Handler: middleware.Logging(webapp.Routes()),
+		Handler: stack(webapp.Routes()),
 	}
 
 	log.Println("server started, listening on :8080")

src/internal/middleware/logging.go

@@ -6,14 +6,30 @@ import (
 	"time"
 )
 
+type wrappedWriter struct {
+	http.ResponseWriter
+	statusCode int
+}
+
+func (w *wrappedWriter) WriteHeader(statusCode int) {
+	w.ResponseWriter.WriteHeader(statusCode)
+	w.statusCode = statusCode
+}
+
 // LoggingMiddleware logs details about each incoming HTTP request.
 func Logging(next http.Handler) http.Handler {
 	return http.HandlerFunc(func(w http.ResponseWriter, r *http.Request) {
 		start := time.Now()
 
-		// Call the next handler
-		next.ServeHTTP(w, r)
+		wrapped := &wrappedWriter{
+			ResponseWriter: w,
+			statusCode:     http.StatusOK,
+		}
 
-		log.Printf("[request] %s %s from %s (%v)", r.URL.Path, r.Method, r.RemoteAddr, time.Since(start))
+		// Call the next handler
+		next.ServeHTTP(wrapped, r)
+
+		log.Printf("[request] %d %s %s from %s (%v)",
+			wrapped.statusCode, r.Method, r.URL.Path, r.RemoteAddr, time.Since(start))
 	})
 }

src/internal/middleware/middleware.go

@@ -0,0 +1,15 @@
+package middleware
+
+import "net/http"
+
+type Middleware func(http.Handler) http.Handler
+
+func CreateStack(xs ...Middleware) Middleware {
+	return func(next http.Handler) http.Handler {
+		for i := len(xs) - 1; i >= 0; i-- {
+			x := xs[i]
+			next = x(next)
+		}
+		return next
+	}
+}