I got the Prometheus exporter running but it finally stopped working with OH3.
Fiddling with the really outdated dependencies I ended up doing a complete rewrite. Since there was already an initiative to add metrics to the openHAB core this resulted in two PRs (one to the OH core, one to introduce a new addon to provide the metric endpoint):
- https://github.com/openhab/openhab-core/pull/2133
- https://github.com/openhab/openhab-addons/pull/9890
I got the whole chain running in a development build, see some resulting screenshots here:
https://github.com/pravussum/openhab-addons/blob/io.metrics/bundles/org.openhab.io.metrics/README.md
If anyone is interested in testing this, I can provide you with dev builds of the OH distribution and the addon.