One url for login and dashboard

I want make one url for login and dashboard page example "/admin". In all guides login page has different url with dashboard page example "/login" or "/admin/login". If our dashboard has url "admin" and I not auth, Middleware class Authenticate do

return redirect()->guest('login');

I try change it

return redirect()->action('AuthController@getLogin');

where getLogin

return view('auth.login');

but this call error Action getLogin not defined.

via Chebli Mohamed