I'm migrating existing service metrics to Prometheus, I'm trying to find the cleanest way to export existing executor metrics:
For example if I want to expose:
executorService.getQueue().size()
I could have a gauge that increments on submitting a new task to the executor and decrements when it finishes. However that changes the current metric behavior (and requires quite a bit of refactoring).
If instead I convert it to a collector, then I run into the fact that Prometheus complains about there are duplicate #HELP blocks for the same metric. (This happens because I have multiple executors and am using labels to break them apart).