Handling GraphQL errors

[ollietb]

Q	A
Bug fix?	no
New feature?	yes
BC breaks?	no
Deprecations?	no
Tickets	N/A
License	MIT
Doc PR	api-platform/docs#1142

Porting the functionality from the 2.5.x branch over to master - replaces existing PR #3630

Errors thrown from the platform are caught by GraphQL and can't be logged or tracked in production environments, making it impossible to track down the cause of errors or use error analysers. This PR allows the errors from GraphQL to be handled by the developers by decorating the ErrorHandler. The errors can either logged (though a service like monolog) or sent to a 3rd party error analyser, like Sentry or NewRelic.

[ollietb]

This allows for a decorator to be created to handle the errors, eg

<?php

namespace App\GraphQL\Error;

use ApiPlatform\Core\GraphQl\Error\ErrorHandlerInterface;
use Psr\Log\LoggerInterface;

class ErrorHandler implements ErrorHandlerInterface
{
    /**
     * @var ErrorHandlerInterface
     */
    private ErrorHandlerInterface $errorHandler;

    /**
     * @var LoggerInterface
     */
    private LoggerInterface $logger;

    public function __construct(ErrorHandlerInterface $errorHandler, LoggerInterface $logger)
    {
        $this->errorHandler = $errorHandler;
        $this->logger = $logger;
    }

    public function __invoke(array $errors, callable $formatter)
    {
        foreach ($errors as $error) {
            $this->logger->error('GraphQL Exception', array('exception' => $error));
        }
        $errorHandler = $this->errorHandler;
        return $errorHandler($errors, $formatter);
    }
}

[alanpoulain]

Please add it before $this->debug.

[alanpoulain]

I think the return type could be added as well.

[alanpoulain]

Thanks for this PR!

I think the interface could be registered for autoconfiguration (in ApiPlatformExtension).

I've added some (minor) comments.
Could you fix the CS too?
You can also add a CHANGELOG entry and a PR for the documentation (it's not mandatory, I will do it myself otherwise).

[alanpoulain]

Thanks a lot @ollietb!

[ollietb]

@alanpoulain sorry I've just got back from vacation and in my testing I'm not sure the autowiring is working correctly. tbh I'm not really sure how to set it up. I've been using the decorator which works ok.