why is my rails server logging everything twice?

Question

my rails server seems like it is logging everything twice, not sure what is going on here, what should I do to investigate this ?

Answer 1

In my case this was caused by the rails_12factor gem. This gem adds the rails_stdout_logging gem which sends the logs to standard output. This can be useful in a production environment but not in development when Rails already does it by default.

https://github.com/heroku/rails_12factor#rails-4-logging

The solution is to only add this gem in production:

gem 'rails_12factor', group: :production