Auto redirect to Log In page if user hasn't logged in yet

/**
 *
 * Auto redirect to Log In page if user hasn't logged in yet
 *
 */
add_action( 'init', function(){
    if( ! is_user_logged_in() && $GLOBALS['pagenow'] !== 'wp-login.php' ){
        wp_redirect( add_query_arg( array(
            'auto_login_required'   =>  '1'
        ), wp_login_url() ) );
        exit();
    }
}, 1 );