Allow to enable the performance bar per user or Flipper group

A `performance_team` Flipper group has been created. By default this
group is nil but this can be customized in `gitlab.yml` via the
performance_bar.allowed_group setting.

Signed-off-by: Rémy Coutable <remy@rymai.me>

2 files changed, 27 insertions, 3 deletions

diff --git a/lib/feature.rb b/lib/feature.rb
index 363f66ba60e..853a00c75a4 100644
--- a/lib/feature.rb
+++ b/lib/feature.rb
@@ -54,7 +54,15 @@ class Feature
         adapter = Flipper::Adapters::ActiveRecord.new(
           feature_class: FlipperFeature, gate_class: FlipperGate)
 
-        Flipper.new(adapter)
+        Flipper.new(adapter).tap do
+          register_feature_groups
+        end
+      end
+    end
+
+    def register_feature_groups
+      Flipper.register(:performance_team) do |actor|
+        Gitlab::PerformanceBar.allowed_actor?(actor)
       end
     end
   end
diff --git a/lib/gitlab/performance_bar.rb b/lib/gitlab/performance_bar.rb
index 163a40ad306..2ca2cbeac08 100644
--- a/lib/gitlab/performance_bar.rb
+++ b/lib/gitlab/performance_bar.rb
@@ -1,7 +1,23 @@
 module Gitlab
   module PerformanceBar
-    def self.enabled?
-      Feature.enabled?('gitlab_performance_bar')
+    def self.enabled?(current_user = nil)
+      Feature.enabled?(:gitlab_performance_bar, current_user)
+    end
+
+    def self.allowed_actor?(actor)
+      group = allowed_group
+      return false unless actor&.is_a?(User) && group
+
+      GroupMembersFinder.new(group)
+        .execute
+        .where(user_id: actor.id)
+        .any?
+    end
+
+    def self.allowed_group
+      return nil unless Gitlab.config.performance_bar.allowed_group
+
+      Group.by_path(Gitlab.config.performance_bar.allowed_group)
     end
   end
 end