CodeIgniter 3 - Delegate exceptions and errors to Logentries

hooks.php

<?php
// application/config/hooks.php

defined('BASEPATH') OR exit('No direct script access allowed');

/*
| -------------------------------------------------------------------------
| Hooks
| -------------------------------------------------------------------------
| This file lets you define "hooks" to extend CI without hacking the core
| files.  Please see the user guide for info:
|
|	https://codeigniter.com/user_guide/general/hooks.html
|
*/

$hook['pre_system'] = function() {
    require_once __DIR__ . '/../../vendor/autoload.php';

    $logentriesToken = '{{your-logentries-token}}';
    $monolog = new \Monolog\Logger("MyApp");
    $monolog->pushHandler(new \Logentries\Handler\LogentriesHandler($logentriesToken));

    set_error_handler(function($no, $str, $file, $line, $context) use ($monolog) {

        // delegate to logentries
        try {
            switch ($no) {
                case E_USER_NOTICE:
                    $monolog->info("$str [file: $file, line: $line]");
                    break;
                default:
                    $monolog->error("$str [file: $file, line: $line]");
                    break;
            }
        } catch (\Exception $e) {
            error_log("FAILED to delegate error to logentries: {$e->getMessage()}");
        }

        // call the original error handler
        _error_handler($no, $str, $file, $line, $context);
    });

    set_exception_handler(function($exception) use ($monolog) {

        // delegate to logentries
        try {
            $monolog->error(get_class($exception). ": ". $exception->getMessage());
        } catch (\Exception $e) {
            error_log("FAILED to delegate exception to logentries: {$e->getMessage()}");
        }

        // call original exception handler
        _exception_handler($exception);
    });
};