Rack::Environmental¶ ↑

Never again will you accidentally delete production data! Rack::Environmental adds an indicator badge to your web application so that you can tell whether you’re working with the staging, test, development or production version of your web app.

For bundler-managed applications just include Rack::Environmental in your Gemfile:

gem 'rack-environmental'

Alternatively, you can install Rack::Environmental manually:

$ gem install rack-environmental

This Rack middleware can be used with any Rack application, but here’s how you would use it in Rails. Put the following in config/application.rb:

config.middleware.use Rack::Environmental,
                        :staging =>     { :url => /^staging.+$/   },
                        :test =>        { :url => /^test.+$/      },
                        :development => { :url => /^localhost.+$/ }

When a request comes to your web app, Rack::Environmental compares the URL to the supplied regular expressions. If the URL matches, the name of the environment is displayed at the top of the web page.

Each environment can be further configured:

config.middleware.use Rack::Environmental,
                        :staging =>     { :url => /^staging.+$/,
                                          :color => "yellow",
                                          :size => :large          },
                        :test =>        { :url => /^test.+$/,
                                          :color => "purple",
                                          :style => :badge         },
                        :development => { :url => /^localhost.+$/,
                                          :color => "orange"       }

Here’s the full list of configuration options:

:url        => a regular expression
:style      => either :badge (a transparent, floating badge), :banner (default), or :none (ignore this environment)
:color      => a string that represents a CSS color, such as "red", "rgb(6,70,14)", or "#8e6630"
:size       => :small, :medium, or :large; defaults to :medium
:opacity    => a number from 0 (completely transparent) to 1; only works with the badge style
:top        => distance in pixels from the top; only works with the badge style
:left       => distance in pixels from the left; only works with the badge style
:background => true or false; when true, the body's background color is changed

If there’s a context where you want Rack::Environmental to specifically ignore your requests, such as a Jasmine test runner which returns essentially empty files to be built on by the test runner, you can “shut off” Rack::Environmental for that context by adding ‘:style => :none` to its options.