rails 4: Rails.env is different from ENV[“RAILS_ENV”]

Question

I set in my config/environment.rb file ENV["RAILS_ENV"] = "production" in order to run my server on my machine (using rails server ) and get the production behavior. I have a lot of lines in my code that check if Rails.env.production? to assign a different functionality for some of the app components. My problem is that when I check the environment in one of my controller I get different results for Rails.env and ENV["RAILS_ENV"] . The first will show "development" while the second will be "production".

Shouldn't both of the methods return the same value?

Answer 1

By the time config/environment.rb is evaluated you're just modifying the ENV hash. If you want to run your app in production set the RAILS_ENV environment variable in the shell you use to run rails.

RAILS_ENV=production bundle exec rails c

Answer 2

To run your rails server in production mode run :

rails s -e production

And to answer your actual question :

Rails.env uses ENV["RAILS_ENV"] internally, see : https://github.com/rails/rails/blob/d25fe31c40928712b5e08fe0afb567c3bc88eddf/railties/lib/rails.rb#L59-L61

def env
  @_env ||= ActiveSupport::StringInquirer.new(ENV["RAILS_ENV"] || ENV["RACK_ENV"] || "development")
end

but ENV["RAILS_ENV"] which is actually not set till now, so the option that is passed with -e if passed while the rails server command is triggered comes into picture, see:

https://github.com/rails/rails/blob/3e36db4406beea32772b1db1e9a16cc1e8aea14c/railties/lib/rails/commands/server.rb#L62-64

def set_environment
  ENV["RAILS_ENV"] ||= options[:environment]
end

for environment option see: https://github.com/rails/rails/blob/3e36db4406beea32772b1db1e9a16cc1e8aea14c/railties/lib/rails/commands/server.rb#L31

      opts.on("-e", "--environment=name", String,
              "Specifies the environment to run this server under (test/development/production).",
              "Default: development") { |v| options[:environment] = v }

and all this is happening before your applications environment.rb is executed.

Hope this helps.