Firehose & structured metadata

Hi all,

We’re trying to implement AWS CloudWatch logs into Grafana with the Firehose approach.
Although in the basis, this works quite well, but we want to add some structured metadata to those logs based on metadata we get from the CloudWatch log stream.

We added a transform function in the Firehose service, so we can add the logic, however, it doesn’t seem possible to add some structured metadata to the logs. It seems like Grafana adds some structured metadata itself, but it would be great & very beneficial if we could also add that structured metadata to the logs as well via the transform functionality. Like adding an extra field to every record for example.

Just to be clear, I’m not talking about the indexed metadata that can be added via a prefix lbl_ as a component in Firehose, but really structured metadata on a per-log rule.

Is this possible and am I missing something here perhaps?

Thanks!