我想使用php在文本文件中保存完整的会话日志

Question

I would like to save full session logs in text per each day. here is my code to create file and save log.

session_start();

    if(!isset($_SESSION['SESS_MEMBER_ID']) || (trim($_SESSION['SESS_MEMBER_ID']) == '')) {
        header("location: index.php");

        //Write action to txt log
    $log  = "User: ".$_SERVER['REMOTE_ADDR'].' - '.date("F j, Y, g:i a").PHP_EOL.
            "Attempt: ".($result[0]['success']=='1'?'Success':'Failed').PHP_EOL.
            "User: ".($_SESSION['SESS_USER_ID']).PHP_EOL.
            "User Type: ".($_SESSION['SESS_USER_TYPE']).PHP_EOL.
            "-------------------------".PHP_EOL;
    //-
    file_put_contents('./log_'.date("j.n.Y").'.txt', $log, FILE_APPEND);
        //exit();
    }

    $expiry = 60;//session expiry required after 30 mins
    if (isset($_SESSION['LAST']) && (time() - $_SESSION['LAST'] > $expiry)) {
        session_unset();
        session_destroy();
        header("location: logout.php");
    }
    $_SESSION['LAST'] = time();

Its not creating any file so can anyone help me to save session login time, logout time & session activity in text file in root directory