How to use Monolog in any PHP file

If you have to debug code inside an old PHP project which doesn't use some Composer-like goodness, or a spaghetti code single PHP file (urgh!), you could find Monolog (https://github.com/Seldaek/monolog) useful.

Here's how to plug it inside any PHP file:

<?php

spl_autoload_register(function ($class) {
  $file = $__DIR__.'/relative/path/to/Monolog/src/'.strtr($class, '\\', '/').'.php';
  if (file_exists($file)) {
    require $file;
    return true;
  }
});

use Monolog\Logger;
use Monolog\Handler\StreamHandler;

$log = new Logger('name');
$log->pushHandler(new StreamHandler(__DIR__.'/path/to/your.log', Logger::DEBUG));

$log->addInfo('Do your magic here.');