Hello misc@, I have started working on a new filter yesterday which implements a prometheus exporter.
This allows OpenSMTPD to expose metrics which can be scraped by prometheus to generate dashboards: https://twitter.com/PoolpOrg/status/1263089397387464704 It is a work in progress but I don't have much experience with prometheus, so if some of you are prometheus users and want to contribute let me know :-) Gilles