internal/server/http.go

@@ -10,23 +10,39 @@ import (
 // HTTP server configuration constants.
 const (
 	HTTPReadTimeout = 30 * time.Second
+	// HTTPReadHeaderTimeout bounds the request-header read on its own,
+	// short, so a slowloris client dribbling headers is dropped well
+	// before it ties up a connection for the whole ReadTimeout window.
+	HTTPReadHeaderTimeout = 10 * time.Second
 	HTTPWriteTimeout      = 60 * time.Second
+	// HTTPIdleTimeout bounds how long an idle keep-alive connection is
+	// held open, so idle connections cannot accumulate without limit on a
+	// service targeting high concurrency.
+	HTTPIdleTimeout    = 120 * time.Second
 	HTTPMaxHeaderBytes = 8 << 10 // 8KB
 )
 
-func (s *Server) serveUntilShutdown() {
-	listenAddr := fmt.Sprintf(":%d", s.config.Port)
-	s.httpServer = &http.Server{
-		Addr:           listenAddr,
+// newHTTPServer builds the http.Server with the hardening timeouts and
+// limits applied. It is separate from serveUntilShutdown so the
+// configuration can be asserted in a test without binding a listener.
+func (s *Server) newHTTPServer() *http.Server {
+	return &http.Server{
+		Addr:              fmt.Sprintf(":%d", s.config.Port),
 		ReadTimeout:       HTTPReadTimeout,
+		ReadHeaderTimeout: HTTPReadHeaderTimeout,
 		WriteTimeout:      HTTPWriteTimeout,
+		IdleTimeout:       HTTPIdleTimeout,
 		MaxHeaderBytes:    HTTPMaxHeaderBytes,
 		Handler:           s,
 	}
+}
+
+func (s *Server) serveUntilShutdown() {
+	s.httpServer = s.newHTTPServer()
 
 	s.SetupRoutes()
 
-	s.log.Info("http begin listen", "listenaddr", listenAddr)
+	s.log.Info("http begin listen", "listenaddr", s.httpServer.Addr)
 
 	err := s.httpServer.ListenAndServe()
 	if err != nil && !errors.Is(err, http.ErrServerClosed) {