Is it possible to change PHP error log output?

I have configured the error_log directive in my php.ini file, like this:

error_log = /path/to/logs/error_log

And then I configured the error_reporting directive like this:

error_reporting = E_ALL & ~E_DEPRECATED & ~E_STRICT

When I check the error_log file, I see normal PHP warning/error text lines:

[03-Jun-2015 08:39:00 America/Bogota] PHP Notice:  Undefined index: cerrar in /fake/path/to/file2.php on line 68
[03-Jun-2015 08:40:49 America/Bogota] PHP Notice:  Undefined index:  in /fake/path/to/file2.php on line 344

Is there is a way to change output format? I mean, if I can print, for example, the IP address and the subdomain that cause the warning.

I was looking for it on Stack Overflow, in Google Search, and I don’t find clear information or examples.

Answer

So agreeing to and finalizing all the comments given above, the best approach is to set_error_handler.

I wrote a class for you. I also like to set_exception_handler to have a unified experience and save all the errors in Error::$throwables to display them on shutdown instead of the View (handled by View class not provided here).

class Error
{
    public static $error_types = array(
        E_ERROR => 'E_ERROR',
        E_WARNING => 'E_WARNING',
        E_PARSE => 'E_PARSE',
        E_NOTICE => 'E_NOTICE',
        E_CORE_ERROR => 'E_CORE_ERROR',
        E_CORE_WARNING => 'E_CORE_WARNING',
        E_COMPILE_ERROR => 'E_COMPILE_ERROR',
        E_COMPILE_WARNING => 'E_COMPILE_WARNING',
        E_USER_ERROR => 'E_USER_ERROR',
        E_USER_WARNING => 'E_USER_WARNING',
        E_USER_NOTICE => 'E_USER_NOTICE',
        E_STRICT => 'E_STRICT',
        E_RECOVERABLE_ERROR => 'E_RECOVERABLE_ERROR',
        E_DEPRECATED => 'E_DEPRECATED',
        E_USER_DEPRECATED => 'E_USER_DEPRECATED'
    );

    public static $shutdown = FALSE;

    public static $throwables = array();

    public static function set_throwable_handlers()
    {
        ini_set('error_reporting', E_ALL & ~E_DEPRECATED & ~E_STRICT);
        ini_set('display_errors', FALSE);
        ini_set('log_errors', TRUE);
        ini_set('error_log', '/path/to/logs/error_log');

        set_error_handler(array('Error', 'error_handler'));
        set_exception_handler(array('Error', 'exception_handler'));

        register_shutdown_function(array('Error', 'shutdown_handler'));
    }

    public static function set_throwable($error_number, $error_text, $error_file, $error_line, $error_log = TRUE)
    {
        if ($error_log === TRUE)
        {
            //provide any data you want to log to error log
            error_log('PHP ' . self::$error_types[$error_number] . ' : ' . $error_text . ' in ' . $error_file . ' on line ' . $error_line);
        }

        //provide any data you want to class variable
        self::$throwables[$error_number][] = array('type' => self::$error_types[$error_number], 'text' => $error_text, 'file' => $error_file, 'line' => $error_line);
    }

    public static function exception_handler(Exception $exception)
    {
        self::set_throwable($exception->getCode(), $exception->getMessage(), $exception->getFile(), $exception->getLine());
    }

    public static function error_handler($error_number = '', $error_text = '', $error_file = '', $error_line = '')
    {
        self::set_throwable($error_number, $error_text, $error_file, $error_line);
    }

    public static function shutdown_handler()
    {
        $error = error_get_last();

        if ($error !== NULL)
        {
            self::set_throwable($error['type'], $error['message'], $error['file'], $error['line'], FALSE);
        }

        //enables error page on shutdown & displays the throwables
        //self::$shutdown = TRUE;
        //
        //View::display();
    }

    public static function throw_error($error_text, $error_number = E_USER_NOTICE)
    {
        trigger_error($error_text, $error_number);

        exit;
    }
}