class Config
{
    static $dbHost = 'localhost';
    static $dbName = 'name';
    static $dbUser = 'user';
    static $dbPass = 'pass';
}

$this->configService('db', function (ServiceLocator $context) {
    return new PDO(
        'mysql:host=' . Config::$dbHost . ';dbname=' . Config::$dbName . ';charset=utf8',
        Config::$dbUser,
        Config::$dbPass
    );
});

$this->configService('db', function (ServiceLocator $context) {
    $password = Config::$dbPass;
    Config::$dbPass = '';

    return new PDO(
        'mysql:host=' . Config::$dbHost . ';dbname=' . Config::$dbName . ';charset=utf8',
        Config::$dbUser,
        $password
    );
});