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How to use Growthbook(GB) AB system

Differences between GB and existing powr ab system​

  • There is no ab_logs table. Ab assigns durring execution time on controllers.
  • NEW expose table - ab_impressions. This table will be filled out when users have seen particular ab.
  • Now we can manage abs settings on GB dashboard - https://app.growthbook.io/ (login [email protected] by google auth)
  • All abs running rules on GB now we just send attributes and fetch running conditions from their sdk:
app/controllers/concerns/ab/growthbook.rb
def init_ab_features_flags
    growthbook.attributes = {
        logged_in: current_user.present?,
        user_id: current_user&.id,
        unique_id: current_user&.unique_id || cookies[:unique_id],
        platform: current_user&.primary_platform || @host || params[:platform] || (session[:shopify_install_id].present? && "shopify"),
        url: url_for,
        # returns [] if user is free, ['forBuilder_pro_monthly'] if users has eg formbuilder subscription
        levels: current_user&.active_subscriptions_as_string
    }
end

Introduction​

A very quick overview of GrowthBook -

How to create ab feature.​

How to get feature(ab) on frontend side.​

Change feature depends of group and make expose​

How to add target conditions​

Caveats​

Danger zone. Please think twice when and where exposed should be called.​

it uses Ab::GrowthbookImpressionListener that will write record every tine when expose action controller was called.

app/controllers/concerns/ab/growthbook.rb
def growthbook_exposed(experiment_key)
    # Will write record to AbImpression table after calling feature_value]
    growthbook.listener = Ab::GrowthbookImpressionListener.new(current_user, cookies)
    growthbook.feature_value(experiment_key)
end

Purge GB cache.​

Need to pull up new/updated features and target conditions

Fallback::Cache.delete("growthbook_features")

Apply ab feature.​

Call init_ab_features_flags on your controller action that user should see. This method is available on all controllers, eg:

  before_action :init_ab_features_flags, only: :standalone

Get ab groups on frontend​

Call prepare_app_for_front_end on your controller action that user should see. This method is available on all controllers, eg:

app/controllers/users_controller.rb
before_action :prepare_growthbook_frontend_abs, only: :show

Dev/QA tools​

In order to force any abs for test purposes you can apply cookie key gb_forced_abs with groups and variations that you wanna test in your browser, in example bellow:

test_group_1:control|test_group_2:variation_2