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 ?

my gemfile

source 'https://rubygems.org' ruby '2.1.0'  gem 'rails', '4.0.1' gem 'haml-rails' gem 'pg', '~> 0.17.1' gem 'redis' gem 'redis-namespace' gem 'thin', '~> 1.6.1' gem 'rabl' gem 'underscore-rails'  #assets gem 'sass-rails', '~> 4.0.0' gem 'uglifier', '>= 1.3.0' gem 'foundation-rails' gem 'font-awesome-rails'  #javascript gem 'coffee-rails', '~> 4.0.0' gem 'jquery-rails' gem 'jbuilder', '~> 1.2' gem 'angularjs-rails', '~> 1.2.7' gem 'ngmin-rails', '~> 0.4.0'  #user auth gem 'devise', '3.0.0' gem 'omniauth' gem 'omniauth-twitter' gem 'uuidtools'   #misc tools gem 'twitter'  #heroku gem 'rails_12factor'  group :development, :test do   gem 'capybara-webkit', github: 'thoughtbot/capybara-webkit', branch: 'master'   gem 'rspec-rails', '~> 2.14.1'   gem 'factory_girl_rails', '4.2.1'   gem 'mocha', '~> 1.0.0'   gem 'pry'   gem 'pry-debugger'   gem 'quiet_assets'   gem 'parallel_tests'   gem 'zeus-parallel_tests'   gem 'guard-rspec'   gem 'rb-fsevent' end  group :development do    gem 'guard-livereload'   gem 'rack-livereload'   gem 'better_errors'   gem 'terminal-notifier-guard' end  group :test do   gem 'launchy', '>= 2.1.2'   gem 'capybara', '>= 1.1.3'   gem 'database_cleaner', '~> 1.2.0'   gem 'zeus', :require => false   gem 'shoulda-matchers'   gem 'pdf-inspector'   gem 'selenium-webdriver'   gem "mock_redis", "~> 0.11.0" end 

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 

Answer 2

Have a look at this issue

Try adding the following code to you config/application.rb

   if Rails.env.development?         # Don't log to STDOUT, by default rails s will handle it         config.logger = Logger.new('/dev/null')     else         # Don't log to file, sending everything to unicorn file.         config.logger = Logger.new(STDOUT)     end