1 files changed, 45 insertions, 0 deletions
diff --git a/app/controllers/concerns/controller_with_feature_category.rb b/app/controllers/concerns/controller_with_feature_category.rb
new file mode 100644
index 00000000000..f8985cf0950
--- /dev/null
+++ b/app/controllers/concerns/controller_with_feature_category.rb
@@ -0,0 +1,45 @@
+# frozen_string_literal: true
+
+module ControllerWithFeatureCategory
+  extend ActiveSupport::Concern
+  include Gitlab::ClassAttributes
+
+  class_methods do
+    def feature_category(category, config = {})
+      validate_config!(config)
+
+      category_config = Config.new(category, config[:only], config[:except], config[:if], config[:unless])
+      # Add the config to the beginning. That way, the last defined one takes precedence.
+      feature_category_configuration.unshift(category_config)
+    end
+
+    def feature_category_for_action(action)
+      category_config = feature_category_configuration.find { |config| config.matches?(action) }
+
+      category_config&.category || superclass_feature_category_for_action(action)
+    end
+
+    private
+
+    def validate_config!(config)
+      invalid_keys = config.keys - [:only, :except, :if, :unless]
+      if invalid_keys.any?
+        raise ArgumentError, "unknown arguments: #{invalid_keys} "
+      end
+
+      if config.key?(:only) && config.key?(:except)
+        raise ArgumentError, "cannot configure both `only` and `except`"
+      end
+    end
+
+    def feature_category_configuration
+      class_attributes[:feature_category_config] ||= []
+    end
+
+    def superclass_feature_category_for_action(action)
+      return unless superclass.respond_to?(:feature_category_for_action)
+
+      superclass.feature_category_for_action(action)
+    end
+  end
+end