I want a very simple logging solution (since platforms like fly.io do not retain logs). Think, logging K/V pairs from NodeJS that get streamed to some server.

Ideally, the logging solution would be something simple I can spin up in a Dockerfile on fly.io--but I'm also open to using hosted alternatives.

It just seems like things like prometheus/loki are much too heavyweight--for my extremely basic usecase.

The core requirement is simplicity / ease of use. Single-node, very easily dockerized, nothing to think about.