Add usage ping recording finish times

We want the usage ping to be performant, we'd like to see how long it
takes to calculate the ce and the ee usage data

changelogs/unreleased/216157-add-usage-ping-recording_finished_at-field.yml

+---
+title: Record usage ping finish time
+merge_request: 31222
+author:
+type: performance

ee/lib/ee/gitlab/usage_data.rb

@@ -38,7 +38,16 @@ module EE
         def uncached_data
           time_period = { created_at: 28.days.ago..Time.current }
           usage_activity_by_stage_monthly = usage_activity_by_stage(:usage_activity_by_stage_monthly, time_period)
-          super.merge(usage_activity_by_stage).merge(usage_activity_by_stage_monthly)
+          super
+            .merge(usage_activity_by_stage)
+            .merge(usage_activity_by_stage_monthly)
+            .merge(recording_ee_finish_data)
+        end
+
+        def recording_ee_finish_data
+          {
+            recording_ee_finished_at: Time.now
+          }
         end
 
         override :features_usage_data

ee/spec/lib/ee/gitlab/usage_data_spec.rb

@@ -673,6 +673,14 @@ describe Gitlab::UsageData do
     end
   end
 
+  describe '.recording_ee_finished_at' do
+    subject { described_class.recording_ee_finish_data }
+
+    it 'gathers time ee recording finishes at' do
+      expect(subject[:recording_ee_finished_at]).to be_a(Time)
+    end
+  end
+
   def for_defined_days_back(days: [29, 2])
     days.each do |n|
       Timecop.travel(n.days.ago) do

lib/gitlab/usage_data.rb

@@ -35,6 +35,7 @@ module Gitlab
           .merge(components_usage_data)
           .merge(cycle_analytics_usage_data)
           .merge(object_store_usage_data)
+          .merge(recording_ce_finish_data)
       end
 
       def to_json(force_refresh: false)
@@ -43,16 +44,22 @@ module Gitlab
 
       def license_usage_data
         {
+          recorded_at: Time.now, # should be calculated very first
           uuid: alt_usage_data { Gitlab::CurrentSettings.uuid },
           hostname: alt_usage_data { Gitlab.config.gitlab.host },
           version: alt_usage_data { Gitlab::VERSION },
           installation_type: alt_usage_data { installation_type },
           active_user_count: count(User.active),
-          recorded_at: Time.now,
           edition: 'CE'
         }
       end
 
+      def recording_ce_finish_data
+        {
+          recording_ce_finished_at: Time.now
+        }
+      end
+
       # rubocop: disable Metrics/AbcSize
       # rubocop: disable CodeReuse/ActiveRecord
       def system_usage_data

spec/lib/gitlab/usage_data_spec.rb

@@ -151,6 +151,14 @@ describe Gitlab::UsageData, :aggregate_failures do
       end
     end
 
+    describe '.recording_ce_finished_at' do
+      subject { described_class.recording_ce_finish_data }
+
+      it 'gathers time ce recording finishes at' do
+        expect(subject[:recording_ce_finished_at]).to be_a(Time)
+      end
+    end
+
     context 'when not relying on database records' do
       describe '#features_usage_data_ce' do
         subject { described_class.features_usage_data_ce }