Cookie based feature flags implementation for Rails.

Add this line to your application's Gemfile:

gem 'cookie_flag'

And then execute:

$ bundle
$ bundle exec rails generate cookie_flag:install

At first, edit your config/cookie_flag.yml and configure your feature flag name and feature flag secret.

default: &default
  new_feature: '1'

development:
  <<: *default

test:
  <<: *default

production:
  new_feature: <%= ENV['NEW_FEATURE_SECRET'] %>

then, you can use cookie based feature flag API at controllers and views.

If you want to enable or disable features from admin page, you can use console web.

Edit your config/routes.rb

Rails.application.routes.draw do
  mount CookieFlag::Console, at: "/cookie_flag" if Rails.env.development?
end

Use feature class method at controller, you can return 404 response at disabled feature endpoints.

class YourFeaturesController < ApplicationController
  feature :new_feature

  def index
  end
end

And some helper methods feature_available? and feature_flags are available.

class NewFeaturesController < ApplicationController
  def index
    unless feature_available?(:new_feature)
      redirect_to root_path
    end
  end
end

feature_available? helper method is available.

<% if feature_available?(:new_feature) %>
  <p>you can use new feature!</p>
<% else %>
  <p>you cannot use new feature!</p>
<% end %>

Bug reports and pull requests are welcome on GitHub at https://github.com/iguchi1124/cookie_flag.

The gem is available as open source under the terms of the MIT License.