FPM handler is hiding exception details, blank screen

[shadowhand]

Description:

Our system had a check that was throwing an exception early on in application bootstrapping. This exception caused the FPM handler (v3) to display the "white screen of death" with an HTTP 500 error.

I tried to set display_errors=On, display_startup_errors=On in php/conf.d/php.ini but this had no impact; the white screen remained.

How to reproduce:

Set the HANDLER=throws.php with content:

<?php

require __DIR__ . '/vendor/autoload.php';

throw new Exception('Bref hides this exception');

[mnapoli]

This is the usual behavior of PHP (blank 500 http response), and here you were not able to override the option because it is forced here: https://github.com/brefphp/bref/blob/v3/src/FpmRuntime/FpmHandler.php#L87-L90

Usually we don't want to enable this in production at all because the website is publicly hosted. Or as a workaround you could install Woops or another error handler of the sort?

[shadowhand]

@mnapoli we do enable the Slim error handler early on in our code, but this exception was thrown before Slim was initialized.

Could the Bref configuration be modified to at least log the error details? As of right now, the error is completely invisible.

[mnapoli]

The idea is to use logs, not the HTTP response, that could be dangerous to enable that. Do you mean you don't have anything in logs?

[shadowhand]

@mnapoli correct, there is zero information in the PHP logs about the bootstrap exception. Setting log_errors=On in conf/conf.d/php.ini also did not enable logging of errors, at least not in docker logs -tf php output.

[mnapoli]

Got it!

I'm going to test this approach instead for v3: brefphp/aws-lambda-layers#303

[mnapoli]

Latest v3 version should resolve that 👍