Log simplesamlphp error info to syslog, for cross-reference to trackID

gistfile1.php

<?php
/**
 * Class error_show
 *
 * A custom error show method to log some useful additional information.
 */
class error_show {
    public static function show($config, $data) {
        $additional = $data['error'] + ['cookie-headers' => $_COOKIE];
        unset($additional['exceptionMsg']);
        unset($additional['exceptionTrace']);
        $debug = new SimpleSAML_Logger_LoggingHandlerSyslog;
        $debug->setArray($additional);
        $debug->setLogFormat('json');
        $debug->log(SimpleSAML_Logger::NOTICE, '');
        $t = new SimpleSAML_XHTML_Template($config, 'error.php', 'errors');
        $t->data = array_merge($t->data, $data);
        $t->show();
        exit;
    }
}

Depends on PR simplesamlphp/simplesamlphp#311