feature-flags.md

Feature flags

Feature flags in Publisher are managed using the Flipflop gem. The gem is currently configured so that only the "cookie" and "default" strategies are active.

Toggling feature flags

A features dashboard is available to make it easy to toggle features on and off during development. This dashboard can be accessed at /flipflop. Note that this can only be used to toggle feature flags for your user.

Testing with feature flags

For testing purposes, feature flags can be configured like so:

  setup do
    test_strategy = Flipflop::FeatureSet.current.test!
    test_strategy.switch!(:feature_name, true)
  end

Creating a feature flag

To create a new feature flag, create an entry in the features.rb file with this format:

feature :feature_name,
      default: false,
      description: "A description of the feature"

Features should default to false while being worked on, meaning users will not see any change without explicitly turning the feature on using the dashboard.

To route the user between different pages based on the status of a feature flag, use the FeatureConstraint class.

For example:

app/routes.rb

constraints FeatureConstraint.new("feature_name") do
  get "path/to/page" => "new_controller#action"
end
get "path/to/page" => "old_controller#action"

This will route GET requests for /path/to/page to new_controller when the feature flag is enabled, and to old_controller when it is disabled.