Metadata enrichment

It is possible to add additional metadata to persisted events. This is useful for recording extra contextual (auditing) data such as the currently logged in user, an IP address, a user agent or some request token.

The metadata enricher is automatically registered when adding the following tag to the service definition:

tags: [broadway.metadata_enricher]

IP address example

use Broadway\Domain\Metadata;
use Broadway\EventSourcing\MetadataEnrichment\MetadataEnricher;
use Symfony\Component\HttpFoundation\Request;
use Symfony\Component\HttpFoundation\RequestStack;

class IpAddressMetadataEnricher implements MetadataEnricher
{
    private $requestStack;

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

    public function enrich(Metadata $metadata): Metadata
    {
        return $metadata->merge(
            Metadata::kv(
                'ip_address',
                $this->getClientIp()
            )
        );
    }

    private function getClientIp(): string
    {
        $currentRequest = $this->requestStack->getCurrentRequest();

        return $currentRequest instanceof Request ? $currentRequest->getClientIp() : '';
    }
}

# services.yaml
my_ip_address_metadata_enricher:
    class: IpAddressMetadataEnricher
    arguments:
      - "[@request_stack](https://github.com/request_stack)"
    tags:
      - { name: broadway.metadata_enricher }