Metadata enricher

[MattKetmo]

Hello,

Here is a small plugin I wrote for a project to easily add custom metadata to all events. The code is inspired from event-store-bus-bridge/src/TransactionManager.php#L54.

In my case I use it to add information about the user who caused the events.

The PR is missing the tests and some phpdoc but I prefer to ask before, to know if you want the feature in this package or prefer having it elsewhere (or maybe you don't want it).

I also consider to configure it in the Container via something like:

return [
    'prooph' => [
        'event_store' => [
            'metadata_enrichers' => [
                UserMetadataEnricher::class,
                OtherMetadataEnricher::class,
            ],
    // ...

(Btw this is also something Broadway brings natively ;))

[prolic]

i would suggest the name MetadataEnricherAggregate

[prolic]

I like it. Let's add some phpdoc and test-coverage back to 100% :-)
@codeliner additional thoughts?

[codeliner]

I like it, too. It reminds me on refactoring the TransactionManager so that causation_id and causation_name are no longer added by the TransactionManager. If the MetadataEnricherPlugin is available we can change the behavior of TransactionManager with the next major release.

[prolic]

@MattKetmo can you submit the pr to the develop branch, please?

[MattKetmo]

ok, I will do it tomorrow

[MattKetmo]

PR submitted in develop branch with tests and phpdoc #162.