Add latest changes from gitlab-org/gitlab@master

1 files changed, 29 insertions, 4 deletions

diff --git a/app/experiments/application_experiment.rb b/app/experiments/application_experiment.rb
index 1c9a3c5f37f..663c58ceda6 100644
--- a/app/experiments/application_experiment.rb
+++ b/app/experiments/application_experiment.rb
@@ -23,16 +23,41 @@ class ApplicationExperiment < Gitlab::Experiment # rubocop:disable Gitlab/Namesp
     ))
   end
 
+  def rollout_strategy
+    # no-op override in inherited class as desired
+  end
+
+  def variants
+    # override as desired in inherited class with all variants + control
+    # %i[variant1 variant2 control]
+    #
+    # this will make sure we supply variants as these go together - rollout_strategy of :round_robin must have variants
+    raise NotImplementedError, "Inheriting class must supply variants as an array if :round_robin strategy is used" if rollout_strategy == :round_robin
+  end
+
   private
 
+  def feature_flag_name
+    name.tr('/', '_')
+  end
+
   def resolve_variant_name
-    return variant_names.first if Feature.enabled?(feature_flag_name, self, type: :experiment, default_enabled: :yaml)
+    case rollout_strategy
+    when :round_robin
+      round_robin_rollout
+    else
+      percentage_rollout
+    end
+  end
 
-    nil # Returning nil vs. :control is important for not caching and rollouts.
+  def round_robin_rollout
+    Strategy::RoundRobin.new(feature_flag_name, variants).execute
   end
 
-  def feature_flag_name
-    name.tr('/', '_')
+  def percentage_rollout
+    return variant_names.first if Feature.enabled?(feature_flag_name, self, type: :experiment, default_enabled: :yaml)
+
+    nil # Returning nil vs. :control is important for not caching and rollouts.
   end
 
   # Cache is an implementation on top of Gitlab::Redis::SharedState that also