I’ve published to hex Logbook, our Logger wrapper that’we use on a couple of rather big projects. Has been around since early 2019, but just now added to hex.pm

GitHub Repo: GitHub - VoiSmart/logbook: Another opinionated logger for Elixir, with the addition of tag/module based logging. · GitHub
Docs: Logbook — logbook v4.0.0
Hex.pm: logbook | Hex

Basically is a Logger wrapper that adds categories (or tags) to each logger entry, and each tag can have it’s own log level. As a bonus, module names are automatically tracked as tags and a specific log level can be set for them, too.

Intended usage: activate a specific log level for a specific module only, or a specific log level for a tag (or a group of tags) that may spread across different modules.

By design, the “global” Elixir Logger level still wins: you cannot activate a debug level for a tag and have it emitted if the global Logger level is higher (set on :error for example). But if all the codebase uses Logbook instead of Logger this is not really a problem.

We built it because on our large application, we have different subsystems running, and just enabling a more verbose logger level is a no-go, since too many logs are emitted and is difficult to follow what is going on (or puts too much pressure on the Logger reducing overall performances). With Logbook we can nail down what we want to see and investigate more freely.

The library is pretty solid, is running in production on several systems since the beginning.