Add login/logout menu to WordPress main menu

wp login logout main menu

/* =====================================================
	Login/logout menu button
===================================================== */
add_filter('wp_nav_menu_items', 'add_login_logout_link', 10, 2);
function add_login_logout_link($items, $args) {
	if( $args->theme_location == 'primary-menu' ) {
		ob_start();
        wp_loginout(get_permalink());
        $loginoutlink = ob_get_contents();
        ob_end_clean();
        $items .= '<li class="fr">'. $loginoutlink .'</li>';
	}
    return $items;
}