At this point Prometheus is pretty close to becoming the boring technology. The latest versions have finally brought in the plumbing and tuning knobs to protect against [most] overly expensive queries. So you can't easily take it down anymore.

The single-binary approach is still a problem, though. In my mind any serious telemetry collection stack should separate the query engine and ingestion path from each other - Prometheus has both the query interface and the ingestion/writing subsystem in the same process.[ß]

As for the parent poster: you certainly want to push telemetry out on every event, but the mechanism has to be VERY lightweight. With prometheus the solution is to have a telemetry collection/aggregation agent on the host, feed it with the event data and have prometheus scrape the agent. Statsd with the KV extension is a great protocol for shoveling the telemetry out from the process and into the agent.

ß: you can get around this with Thanos + Trickster to take care of the read path only, but it's quite a bit more complex than plain Prometheus.