Laravel 5.4 Route [login] not defined

Hi I have following route and constructor in my controller i want to check if user is authenticated or not if not then redirect to /warehouse/login page. but for some reasons i am getting Route [login] not defined error.

Constructor:

public function __construct()
    {
        $this->middleware('auth');
        $this->middleware(function ($request, $next) {
            if (!Auth::check()) {
                $url = URL::current();
                $routeName = Route::currentRouteName();

                if ($routeName != "AdminLogin" && $routeName != 'admin') {
                    Session::put('pre_admin_login_url', $url);
                }
                return redirect('/warehouse/login');
            }

            return $next($request);

        }, array('except' => array('WarehouseAdminLogin', 'WarehouseAdminVerify')));


    }

Routes:

Route::get('/warehouse', 'WarehouseController@index');
Route::get('/warehouse/login', array('as' => 'WarehouseAdminLogin', 'uses' => 'WarehouseController@login'));

via Chebli Mohamed