gitlab-org--gitlab-foss/lib/gitlab/experimentation.rb

# frozen_string_literal: true

# == Experimentation
#
# Utility module for A/B testing experimental features. Define your experiments in the `EXPERIMENTS` constant.
# Experiment options:
# - tracking_category (optional, used to set the category when tracking an experiment event)
# - use_backwards_compatible_subject_index (optional, set this to true if you need backwards compatibility)
#
# The experiment is controlled by a Feature Flag (https://docs.gitlab.com/ee/development/feature_flags/controls.html),
# which is named "#{experiment_key}_experiment_percentage" and *must* be set with a percentage and not be used for other purposes.
#
# To enable the experiment for 10% of the users:
#
# chatops: `/chatops run feature set experiment_key_experiment_percentage 10`
# console: `Feature.enable_percentage_of_time(:experiment_key_experiment_percentage, 10)`
#
# To disable the experiment:
#
# chatops: `/chatops run feature delete experiment_key_experiment_percentage`
# console: `Feature.remove(:experiment_key_experiment_percentage)`
#
# To check the current rollout percentage:
#
# chatops: `/chatops run feature get experiment_key_experiment_percentage`
# console: `Feature.get(:experiment_key_experiment_percentage).percentage_of_time_value`
#

# TODO: see https://gitlab.com/gitlab-org/gitlab/-/issues/217490
module Gitlab
  module Experimentation
    EXPERIMENTS = {
      onboarding_issues: {
        tracking_category: 'Growth::Conversion::Experiment::OnboardingIssues',
        use_backwards_compatible_subject_index: true
      },
      ci_notification_dot: {
        tracking_category: 'Growth::Expansion::Experiment::CiNotificationDot',
        use_backwards_compatible_subject_index: true
      },
      upgrade_link_in_user_menu_a: {
        tracking_category: 'Growth::Expansion::Experiment::UpgradeLinkInUserMenuA',
        use_backwards_compatible_subject_index: true
      },
      invite_members_version_a: {
        tracking_category: 'Growth::Expansion::Experiment::InviteMembersVersionA',
        use_backwards_compatible_subject_index: true
      },
      invite_members_version_b: {
        tracking_category: 'Growth::Expansion::Experiment::InviteMembersVersionB',
        use_backwards_compatible_subject_index: true
      },
      invite_members_empty_group_version_a: {
        tracking_category: 'Growth::Expansion::Experiment::InviteMembersEmptyGroupVersionA',
        use_backwards_compatible_subject_index: true
      },
      contact_sales_btn_in_app: {
        tracking_category: 'Growth::Conversion::Experiment::ContactSalesInApp',
        use_backwards_compatible_subject_index: true
      },
      customize_homepage: {
        tracking_category: 'Growth::Expansion::Experiment::CustomizeHomepage',
        use_backwards_compatible_subject_index: true
      },
      invite_email: {
        tracking_category: 'Growth::Acquisition::Experiment::InviteEmail',
        use_backwards_compatible_subject_index: true
      },
      group_only_trials: {
        tracking_category: 'Growth::Conversion::Experiment::GroupOnlyTrials',
        use_backwards_compatible_subject_index: true
      },
      default_to_issues_board: {
        tracking_category: 'Growth::Conversion::Experiment::DefaultToIssuesBoard',
        use_backwards_compatible_subject_index: true
      },
      jobs_empty_state: {
        tracking_category: 'Growth::Activation::Experiment::JobsEmptyState'
      },
      remove_known_trial_form_fields: {
        tracking_category: 'Growth::Conversion::Experiment::RemoveKnownTrialFormFields'
      },
      trimmed_skip_trial_copy: {
        tracking_category: 'Growth::Conversion::Experiment::TrimmedSkipTrialCopy'
      }
    }.freeze

    class << self
      def get_experiment(experiment_key)
        return unless EXPERIMENTS.key?(experiment_key)

        ::Gitlab::Experimentation::Experiment.new(experiment_key, **EXPERIMENTS[experiment_key])
      end

      def active?(experiment_key)
        experiment = get_experiment(experiment_key)
        return false unless experiment

        experiment.active?
      end

      def in_experiment_group?(experiment_key, subject:)
        return false if subject.blank?
        return false unless active?(experiment_key)

        experiment = get_experiment(experiment_key)
        return false unless experiment

        experiment.enabled_for_index?(index_for_subject(experiment, subject))
      end

      private

      def index_for_subject(experiment, subject)
        index = if experiment.use_backwards_compatible_subject_index
                  Digest::SHA1.hexdigest(subject_id(subject)).hex
                else
                  Zlib.crc32("#{experiment.key}#{subject_id(subject)}")
                end

        index % 100
      end

      def subject_id(subject)
        if subject.respond_to?(:to_global_id)
          subject.to_global_id.to_s
        elsif subject.respond_to?(:to_s)
          subject.to_s
        else
          raise ArgumentError.new('Subject must respond to `to_global_id` or `to_s`')
        end
      end
    end
  end
end