Mostly to be able to analyze them, I’m having all my logs written in JSON format.

This logger can format your logs for you: https://github.com/JordiPolo/lorekeeper

It is also very fast, writting down 8 different fields (message, timestamp, trace_id, request_id, parent_id, app_name, app_version, machine_name), it is only 15% slower than the Ruby’s library standand Logger. Very much worth the functionality!