Options to catch NotFoundHttpException

[kAlvaro]

We're using Symfony/4.4 (to be upgraded later this year). Invalid URL requests end up in our logs as uncaught exceptions (and also submitted to Sentry):

request.ERROR Uncaught PHP Exception Symfony\Component\HttpKernel\Exception\NotFoundHttpException: "No route found for "GET /this-page-does-not-exist/"" at /var/www/symfony/vendor/symfony/http-kernel/EventListener/RouterListener.php line 136

It's fine to have them logged so we can investigate, but they're almost never an error on our side and we're afraid they can mask actual errors. I've found two ways to have a custom log entry (event subscriber and listener both work for that) but I still get the default uncaught exception entry. The only way to avoid that is to craft a response in the subscriber/listener, but that means losing the default Twig template.

What are my options handle this? Namely:

• Get NotFoundHttpException logged as e.g. notice with a custom text.
• Make Symfony use the default templates.

[lyrixx]

You can configure monolog to ignore all 404. https://symfony.com/doc/current/logging/monolog_exclude_http_codes.html

[kAlvaro]

This looks exactly what I want, but:

You can only use excluded_http_codes/excluded_404s with a FingersCrossedHandler definition

I currently have type: stream. Do I need type: fingers_crossed?

Edit 1: oh, it seems easy to set up: https://symfony.com/doc/current/logging.html

Edit 2: It isn't. I could use some example. My current settings are:

monolog:
  handlers:
    file_log:
      type: stream
      path: '%kernel.logs_dir%/%kernel.environment%.log'
      level: debug
      channels: ['!event']
      formatter: Reacted\Namespace\LoggerFormatterHelper
    console:
      type: console
      channels: ['!event', '!doctrine']

`

[lyrixx]

Another option is to configure the log level for each exception
See this PR #42244

[kAlvaro]

I've given up on the template (after all, it's the default Symfony one so I'm sure nobody in Business asked for it) and just generated a response in the subscriber to let Symfony know I handled it myself:

            $response = new Response('404 Not Found', headers: ['Content-Type' => 'text/plain']);
            $event->setResponse($response);

Per exception log level requires 5.4 so I'll have a look once we're able to upgrade.