Feature

A group based feature switching framework.

Installation

$ gem install feature

Usage

Feature groups and members are stored in a backend. Right now the only included backend is for Redis.

A Feature can be enabled globally or through groups. Group settings only apply when the feature is turned off globally. In other words, if the feature is enabled globally then the group settings are ignored.

Defining Groups and Features

In Rails, modify config/initializers/feature.rb, and add a call to feature, passing in the name of the feature as a symbol, and what you want the default to be. The default will be used when the feature hasn't been explicitly enabled or disabled.

Feature.configure do
  backend Feature::RedisBackend.new(...)

  feature :v2_design, default: false, groups: %w(beta_users employees)
end

Checking if a Feature is Enabled

Calling Feature(:feature_name) will return a Feature instance. This can be interrogated for its current state.

Feature(:v2_design).enabled?   # => false

Check if a feature is enabled for a given group member (gets checked against the defined groups for the feature):

Feature(:v2_design).enabled_for?(current_user.id)

Check if a feature is enabled for ALL given group members:

# True if enabled for id-1 AND id-2
Feature(:v2_design).enabled_for_all?(["id-1", "id-2"])

Check if a feature is enabled for ANY in a given array

# True if enabled for id-1 or id-2
Feature(:v2_design).enabled_for_any?(["id-1", "id-2"])

Enabling and Disabling Features Globally

Just call enable or disable on a Feature.

Feature(:v2_design).enable
Feature(:v2_design).enabled?   # => true
Feature(:v2_design).disable
Feature(:v2_design).enabled?   # => false

Changing Groups membership at runtime

It is possible to change a group membership at during runtime.

Examples from a Ruby irb session:

# Add user to the 'employees' group
Feature.add_to_group(:employees, user.id)

# Remove user from the 'employees' group
Feature.remove_from_group(:employees, user.id)

Dashboard

The dashboard allows features to be globally enabled / disabled and for members to be added and removed from groups.

To mount it in your Rails 3 app, add the following to your routes.rb

mount Feature::Dashboard, at: '/path/to/dashboard'