RequestIdProcessor.php

<?php

namespace App\Logger\Processor;

use Symfony\Component\HttpFoundation\RequestStack;

class RequestIdProcessor
{
    private $requestStack;

    public function __construct(RequestStack $requestStack)
    {
        $this->requestStack = $requestStack;
    }

    public function processRecord($record)
    {
        $request = $this->requestStack->getCurrentRequest();

        if($request !== null) {
            $requestId = $request->headers->get('X-Request-ID');

            if ($requestId !== null) {
                $record['extra']['x_request_id'] = $requestId;
            }
        }

        return $record;
    }
}

RequestIdProcessorSpec.php

<?php

namespace spec\App\Logger\Processor;

use App\Logger\Processor\RequestIdProcessor;
use PhpSpec\ObjectBehavior;
use Prophecy\Argument;
use Symfony\Component\HttpFoundation\RequestStack;
use Symfony\Component\HttpFoundation\Request;
use Symfony\Component\HttpFoundation\HeaderBag;


class RequestIdProcessorSpec extends ObjectBehavior
{
    public function let(RequestStack $requestStack, Request $request, HeaderBag $headers)
    {
        $request->headers = $headers;
        $requestStack->getCurrentRequest()->willReturn($request);

        $this->beConstructedWith($requestStack);
    }

    function it_is_initializable()
    {
        $this->shouldHaveType(RequestIdProcessor::class);
    }

    function it_adds_x_request_id_header_as_an_extra_field(RequestStack $requestStack, HeaderBag $headers, Request $request)
    {
        $headers->get('X-Request-ID')->shouldBeCalled()->willReturn('foo');
        $requestStack->getCurrentRequest()->shouldBeCalled()->willReturn($request);

        $this->processRecord(['extra' => []])->shouldBe(['extra' => ['x_request_id' => 'foo']]);
    }

    function it_does_not_add_the_extra_field_if_header_is_not_set(HeaderBag $headers)
    {
        $headers->get('X-Request-ID')->willReturn(null);

        $this->processRecord(['extra' => []])->shouldBe(['extra' => []]);
    }

    function it_does_not_add_the_extra_field_if_not_in_requestcontext(RequestStack $requestStack)
    {
        $requestStack->getCurrentRequest()->willReturn(null);

        $this->processRecord(['extra' => []])->shouldBe(['extra' => []]);
    }
}

RequestIdResponseListener.php

<?php

namespace App\EventListener;

use Symfony\Component\HttpKernel\Event\FilterResponseEvent;
use Psr\Log\LoggerInterface;

class RequestIdResponseListener
{
    private const LOG_NO_HEADER = 'No X-Request-ID header was found in the request. Response won\'t have it';

    private $logger;

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

    public function onKernelResponse(FilterResponseEvent $event)
    {
        $request = $event->getRequest();
        $response = $event->getResponse();

        $header = $request->headers->get('X-Request-ID');

        if($header === null) {
            $this->logger->warning(self::LOG_NO_HEADER);
            return;
        }

        $response->headers->set('X-Request-ID', $request->headers->get('X-Request-ID'));
    }
}

RequestIdResponseListenerSpec.php

<?php

namespace spec\App\EventListener;

use App\EventListener\RequestIdResponseListener;
use PhpSpec\ObjectBehavior;
use Prophecy\Argument;
use Symfony\Component\HttpKernel\Event\FilterResponseEvent;
use Symfony\Component\HttpFoundation\Request;
use Symfony\Component\HttpFoundation\Response;
use Symfony\Component\HttpFoundation\HeaderBag;
use Psr\Log\LoggerInterface;

class RequestIdResponseListenerSpec extends ObjectBehavior
{
    public function let(FilterResponseEvent $event, Request $request, Response $response, HeaderBag $requestHeaders, HeaderBag $responseHeaders, LoggerInterface $logger)
    {
        $request->headers = $requestHeaders;
        $response->headers = $responseHeaders;

        $event->getRequest()->willReturn($request);
        $event->getResponse()->willReturn($response);

        $this->beConstructedWith($logger);
    }

    function it_is_initializable()
    {
        $this->shouldHaveType(RequestIdResponseListener::class);
    }

    function it_adds_x_request_id_header_in_the_response(FilterResponseEvent $event, Request $request, Response $response, HeaderBag $requestHeaders, HeaderBag $responseHeaders)
    {
        $event->getRequest()->shouldBeCalled()->willReturn($request);
        $requestHeaders->get('X-Request-ID')->shouldBeCalled()->willReturn('foo');
        $event->getResponse()->shouldBeCalled()->willReturn($response);
        $responseHeaders->set('X-Request-ID', 'foo')->shouldBeCalled();

        $this->onKernelResponse($event);
    }

    function it_does_not_add_header_if_not_present_in_request(FilterResponseEvent $event, Request $request, Response $response, HeaderBag $requestHeaders, HeaderBag $responseHeaders, LoggerInterface $logger)
    {
        $requestHeaders->get('X-Request-ID')->willReturn(null);
        $responseHeaders->set('X-Request-ID', Argument::any())->shouldNotBeCalled();
        $logger->warning('No X-Request-ID header was found in the request. Response won\'t have it')->shouldBeCalled();

        $this->onKernelResponse($event);
    }
}