Custom service discovery endpoints with HTTP SD

For several years after Prometheus’ release, a moratorium existed on implementing custom service providers – that is, pull requests to Prometheus to add new service discovery providers would not be accepted. The logic behind this was that it was too much of a burden on Prometheus maintainers to be taking on responsibility for newly implemented service discovery providers and reviewing new submissions when other, more high-priority work could be focused on instead. However, at the end of 2019, that moratorium was lifted.

As expected, the number of service discovery providers increased significantly from 11 before the end of the moratorium to 25 at the time of writing. However, not everything should be a service discovery provider in the upstream Prometheus code base. One of the requirements for accepting a new service discovery provider is that wherever you’re discovering from needs to be well-established and in...