private function init($yaml) {
        // read cache
        if (! $this->readCache()) {
            $cfg = Spyc::YAMLLoad($yaml);
            if (!isset($cfg[$this->env])) {
                $this->env = self::$DEFAULT_ENV;
            }
            $this->configArray = $cfg[$this->env];

            $this->replaceAllConsts($this->configArray);
        }
    }