Feature toggler

In this article you will learn what is our new feature toggler and how to use it.

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What is Feature toggler?

Feature toggler is a RYS functionality. It works similarly to feature flagging and allows you to turn on/off parts or an entire RYS and thus adjusting the overall functionality. It is designed primarily to satisfy client requirements for expected behaviour, but can be used for testing features separately.

Each RYS specifies parts that can be toggled using feature toggler.

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How to work with it?

You can toggle some code based on the database state or by custom definition.

First register features. Put this code into config/initializers.

# Basic definition
# This feature will be active if record on the DB will have active == true
Rys::Feature.add('issue.show')

# For specific plugin
# Preferred way because you can control features directly on plugin settings
Rys::Feature.for_plugin(MyRys::Engine) do
  Rys::Feature.add('my_rys.show')
end

Features have tree structure so if parent is disabled all children are disabled too. For example if issue is disabled -> all issue.* are disabled too regardless to theirs state.

Rys::Feature.add('issue.show')
Rys::Feature.add('issue.show.sidebar')

# issue
# `-- issue.show
#     `-- issue.show.sidebar

You can set default feature state via:

# issue.show is default activated
Rys::Feature.add('issue.show', default_db_status: true)

# issue.show is default deactivated
Rys::Feature.add('issue.show', default_db_status: false)

You can check feature state via:

Rys::Feature.on('issue.show') do
  # issue.show is active
end

if Rys::Feature.active?('issue.show')
  # issue.show is active
end

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Callbacks

You can define action which will be triggered after a status change.

Rys::Feature.add('issue.show', status_changed: lambda { |active| ... })

In routes

You can easily turn on/off routes.

get 'path', rys_feature: 'issue.show'
rys_feature 'issue.show' do
  get 'path'
end

In patches

More details can be found at Patch management section.

instance_methods(feature: 'issue.show') do
  def show
    # Something todo
    # if feature is active
    super
  end
end

Custom condition

If you do not want to use DB records for state checking, you can define custom conditions.

# Ruby block state
# Will be active on 10% of the case
Rys::Feature.add('issue.show') do
  rand(0..10) == 1
end

or you can use both approaches by:

Rys::Feature.add('issue.show') do
  rand(0..10) == 1 && RysFeatureRecord.active?('issue.show')
end

Translations

All features have title and description. You can set them via language file or via options.

Rys::Feature.add('issue.show')
# => I18n.t 'rys_features.issue_show.title'
# => I18n.t 'rys_features.issue_show.description'

Rys::Feature.add('issue.show', title: :feature_title,
                               description: :feature_description)
# => I18n.t 'feature_title'
# => I18n.t 'feature_description'