Feature

Feature is a battle-tested feature toggle library for ruby.

The feature toggle functionality has to be configured by feature repositories. A feature repository simply provides lists of active features (symbols!). Unknown features are assumed inactive. With this approach Feature is higly configurable and not bound to a specific kind of configuration.

NOTE: Ruby 1.8 is only supported until version 0.7.0. Later Versions require at least Ruby 1.9.

CI status

Installation

    gem install feature

How to use

• Setup Feature

  • Create a repository (see examples below)

  • set repository to Feature

    Feature.set_repository(your_repository)
    

• Use Feature in your production code

  Feature.active?(:feature_name) # => true/false
  
  Feature.inactive?(:feature_name) # => true/false
  
  Feature.with(:feature_name) do
    # code
  end
  
  Feature.without(:feature_name) do
    # code
  end
  
  Feature.switch(:feature_name, value_true, value_false) # => returns value_true if :feature_name is active, otherwise value_false
  
  # May also take Procs (here in Ruby 1.9 lambda syntax), returns code evaluation result.
  Feature.switch(:feature_name, -> { code... }, -> { code... })
  

• Use Feature in your test code (for reliable testing of feature depending code)

  require 'feature/testing'
  
  Feature.run_with_activated(:feature_name) do
    # your test code
  end
  
  Feature.run_with_deactivated(:feature_name) do
    # your test code
  end
  

Examples

Vanilla Ruby using SimpleRepository

    # setup code
    require 'feature'

    repo = Feature::Repository::SimpleRepository.new
    repo.add_active_feature :be_nice

    Feature.set_repository repo

    # production code
    Feature.active?(:be_nice)
    # => true

    Feature.with(:be_nice) do
      puts "you can read this"
    end

Rails using YamlRepository

    # File: Gemfile
    gem 'feature'

    # File: config/feature.yml
    features:
        an_active_feature: true
        an_inactive_feature: false

    # File: config/initializers/feature.rb
    repo = Feature::Repository::YamlRepository.new("#{Rails.root}/config/feature.yml")
    Feature.set_repository repo

    # File: app/views/example/index.html.erb
    <% if Feature.active?(:an_active_feature) %>
      <%# Feature implementation goes here %>
    <% end %>

You may also specify a Rails environment to use a new feature in development and test, but not production:

    # File: config/feature.yml
    development:
        features:
            a_new_feature: true
    test:
        features:
            a_new_feature: true
    production:
        features:
            a_new_feature: false

    # File: config/initializers/feature.rb
    repo = Feature::Repository::YamlRepository.new("#{Rails.root}/config/feature.yml", Rails.env)
    Feature.set_repository repo

Rails using ActiveRecordRepository

    # File: Gemfile
    gem 'feature'

    # Run generator and migrations
    $ rails g feature:install
    $ rake db:migrate

    # Add Features to table FeaturesToggle for example in
    # File: db/schema.rb
    FeatureToggle.create!(name: "ActiveFeature", active: true)
    FeatureToggle.create!(name: "InActiveFeature", active: false)

    # or in initializer
    # File: config/initializers/feature.rb
    repo.add_active_feature(:active_feature)

    # File: app/views/example/index.html.erb
    <% if Feature.active?(:an_active_feature) %>
      <%# Feature implementation goes here %>
    <% end %>