I found this. It seems kind of ugly to just throw this into environment.rb. The question is kind of old. I just wanted to ask if there was a better way to do this now.
The problem (if you don't want to click through), is including your custom log message formatter. (The problem I'm solving is that I want to assign a guid to every request, prepend all log messages from that request with the guid, and then return the guid in meta data to the client a.k.a. request id)