Rails: Redirect the Logger output temporary aka show Rails logs in the console

Most of the time, when you are interested in any log output,

you see the logs directly on your console
or you tail / grep some logfile in a separater terminal window

In rare cases it's helpful, to redirect the Logger output temporary to e.g. STDOUT.

Rails.logger = Logger.new(STDOUT)
ActiveRecord::Base.logger = Logger.new(STDOUT)

User.save!
#=> D, [2025-09-08T11:12:26.683106 #1094157] DEBUG -- :   User Load (1.1ms)  SELECT "users".* FROM "users" ORDER BY "users"."id" DESC LIMIT $1  [["LIMIT", 1]]

Many frameworks in Rails have there own logger configuration and are set on boot. We set ActiveRecord::Base.logger in the example, but logger exists also for e.g. ActiveStorage.logger and so on.

Consider to reset the logger settings afterwards in a non temporary context:

rails_logger_was = Rails.logger
active_record_logger_was = ActiveRecord::Base.logger

begin
  Rails.logger = Logger.new(STDOUT)
  ActiveRecord::Base.logger = Logger.new(STDOUT)
  User.save!
ensure
  Rails.logger = rails_logger_was
  ActiveRecord::Base.logger = active_record_logger_was
end

Emanuel

makandra.com

Say thanks

Last edit

2025-09-08

Emanuel

License

Source code in this card is licensed under the MIT License.

Posted by Emanuel to makandra dev (2025-09-08 08:25)