src/Server.php
static function app(string $app) : self {
        if (!isset(self::$_apps[$app]))
            Console::fatal("Failed to fetch app. App \"$app\" not exist!");
        return self::$_apps[$app];
    }
static function app(string $app) : self {
        if (!isset(self::$_apps[$app]))
            Console::fatal("Failed to fetch app. App \"$app\" not exist!");
        return self::$_apps[$app];
    }
选择服务

@param string $app
@return Server