code: public static function init($app = 'text', $version = '', $logPath = '/data/log', $timeZone = 'Asia/Shanghai')
      {
          if (!self::$_instance) {
              date_default_timezone_set($timeZone);
              self::$_app = $app;
              self::$_logPath = realpath($logPath);
              self::$_instance = new self();
          }
          return self::$_instance;
      }
docs: 初始化全局配置变量
  @param string $app
  @param string $logPath
  @param string $timeZone
  @param bool $debug