Expose average durations for the VSA chart

ee/app/controllers/groups/analytics/cycle_analytics/stages_controller.rb

@@ -9,7 +9,7 @@ module Groups
 
         before_action :load_group
         before_action :load_value_stream
-        before_action :validate_params, only: %i[median average records duration_chart]
+        before_action :validate_params, only: %i[median average records duration_chart average_duration_chart]
 
         def index
           return render_403 unless can?(current_user, :read_group_cycle_analytics, @group)
@@ -69,6 +69,12 @@ module Groups
           render json: ::Analytics::CycleAnalytics::DurationChartItemEntity.represent(data_collector.duration_chart_data)
         end
 
+        def average_duration_chart
+          return render_403 unless can?(current_user, :read_group_stage, @group)
+
+          render json: ::Analytics::CycleAnalytics::DurationChartAverageItemEntity.represent(data_collector.duration_chart_average_data)
+        end
+
         private
 
         def data_collector

ee/app/serializers/analytics/cycle_analytics/duration_chart_average_item_entity.rb

+# frozen_string_literal: true
+
+module Analytics
+  module CycleAnalytics
+    class DurationChartAverageItemEntity < Grape::Entity
+      expose :date
+      expose :average_duration_in_seconds
+    end
+  end
+end

ee/config/routes/group.rb

@@ -27,6 +27,7 @@ constraints(::Constraints::GroupUrlConstrainer.new) do
       scope module: :cycle_analytics, as: 'cycle_analytics', path: 'value_stream_analytics' do
         resources :stages, only: [:index, :create, :update, :destroy] do
           member do
+            get :average_duration_chart
             get :duration_chart
             get :median
             get :average
@@ -36,6 +37,7 @@ constraints(::Constraints::GroupUrlConstrainer.new) do
         resources :value_streams, only: [:index, :create, :update, :destroy] do
           resources :stages, only: [:index, :create, :update, :destroy] do
             member do
+              get :average_duration_chart
               get :duration_chart
               get :median
               get :average

ee/lib/ee/gitlab/analytics/cycle_analytics/data_collector.rb

@@ -5,11 +5,24 @@ module EE
     module Analytics
       module CycleAnalytics
         module DataCollector
+          # Deprecated, will be removed in the next milestone: https://gitlab.com/gitlab-org/gitlab/-/issues/328219
           def duration_chart_data
             strong_memoize(:duration_chart) do
-              ::Gitlab::Analytics::CycleAnalytics::DataForDurationChart.new(stage: stage, params: params, query: query).load
+              duration_chart.load
             end
           end
+
+          def duration_chart_average_data
+            strong_memoize(:duration_chart_average_data) do
+              duration_chart.average_by_day
+            end
+          end
+
+          private
+
+          def duration_chart
+            @duration_chart ||= ::Gitlab::Analytics::CycleAnalytics::DataForDurationChart.new(stage: stage, params: params, query: query)
+          end
         end
       end
     end

ee/lib/gitlab/analytics/cycle_analytics/data_for_duration_chart.rb

@@ -22,6 +22,18 @@ module Gitlab
         end
         # rubocop: enable CodeReuse/ActiveRecord
 
+        # rubocop: disable CodeReuse/ActiveRecord
+        def average_by_day
+          date = Arel::Nodes::NamedFunction.new('DATE', [stage.end_event.timestamp_projection])
+          average = round_duration_to_seconds.average
+
+          @query
+            .reorder(nil)
+            .group(date)
+            .select(date.dup.as('date'), average.as('average_duration_in_seconds'))
+        end
+        # rubocop: enable CodeReuse/ActiveRecord
+
         private
 
         attr_reader :stage, :query, :params

ee/spec/fixtures/api/schemas/analytics/cycle_analytics/average_duration_chart.json

+{
+  "type": "array",
+  "items": {
+    "type": "object",
+    "required": ["average_duration_in_seconds", "date"],
+    "properties": {
+      "average_duration_in_seconds": {
+        "type": "integer"
+      },
+      "date": {
+        "type": "string"
+      }
+    },
+    "additionalProperties": false
+  }
+}
+

ee/spec/lib/gitlab/analytics/cycle_analytics/data_collector_spec.rb

@@ -21,6 +21,9 @@ RSpec.describe Gitlab::Analytics::CycleAnalytics::DataCollector do
   shared_examples 'custom Value Stream Analytics Stage' do
     let(:params) { { from: Time.new(2019), to: Time.new(2020), current_user: user } }
     let(:data_collector) { described_class.new(stage: stage, params: params) }
+    let(:resource_1_end_time) { Time.new(2019, 3, 15) }
+    let(:resource_2_end_time) { Time.new(2019, 3, 10) }
+    let(:resource_3_end_time) { Time.new(2019, 3, 20) }
 
     let!(:resource1) do
       # takes 10 days
@@ -28,7 +31,7 @@ RSpec.describe Gitlab::Analytics::CycleAnalytics::DataCollector do
         create_data_for_start_event(self)
       end
 
-      travel_to(Time.new(2019, 3, 15)) do
+      travel_to(resource_1_end_time) do
         create_data_for_end_event(resource, self)
       end
 
@@ -41,7 +44,7 @@ RSpec.describe Gitlab::Analytics::CycleAnalytics::DataCollector do
         create_data_for_start_event(self)
       end
 
-      travel_to(Time.new(2019, 3, 10)) do
+      travel_to(resource_2_end_time) do
         create_data_for_end_event(resource, self)
       end
 
@@ -54,7 +57,7 @@ RSpec.describe Gitlab::Analytics::CycleAnalytics::DataCollector do
         create_data_for_start_event(self)
       end
 
-      travel_to(Time.new(2019, 3, 20)) do
+      travel_to(resource_3_end_time) do
         create_data_for_end_event(resource, self)
       end
 
@@ -93,6 +96,20 @@ RSpec.describe Gitlab::Analytics::CycleAnalytics::DataCollector do
         expect(days).to eq([15, 10, 5])
       end
     end
+
+    describe '#duration_chart_average_data' do
+      subject { data_collector.duration_chart_average_data }
+
+      it 'loads data ordered by event time' do
+        data = subject.map { |item| [item.date, round_to_days(item.average_duration_in_seconds)] }
+
+        expect(Hash[data]).to eq({
+          resource_1_end_time.utc.to_date => 10,
+          resource_2_end_time.utc.to_date => 5,
+          resource_3_end_time.utc.to_date => 15
+        })
+      end
+    end
   end
 
   shared_examples 'test various start and end event combinations' do

ee/spec/lib/gitlab/analytics/cycle_analytics/data_for_duration_chart_spec.rb

+# frozen_string_literal: true
+
+require 'spec_helper'
+
+RSpec.describe Gitlab::Analytics::CycleAnalytics::DataForDurationChart do
+  describe '#average_by_day' do
+    let_it_be(:project) { create(:project, :repository) }
+
+    let(:query) { MergeRequest.joins(:metrics) }
+    let(:merge_time) { 2.days.ago }
+
+    let(:stage) do
+      build(
+        :cycle_analytics_project_stage,
+        start_event_identifier: Gitlab::Analytics::CycleAnalytics::StageEvents::MergeRequestCreated.identifier,
+        end_event_identifier: Gitlab::Analytics::CycleAnalytics::StageEvents::MergeRequestMerged.identifier,
+        project: project
+      )
+    end
+
+    subject(:averages) { described_class.new(stage: stage, params: {}, query: query).average_by_day }
+
+    it 'returns average duration by day' do
+      merge_request1 = create(:merge_request, source_branch: '1', target_project: project, source_project: project, created_at: merge_time - 5.minutes)
+      merge_request2 = create(:merge_request, source_branch: '2', target_project: project, source_project: project, created_at: merge_time - 10.minutes)
+
+      merge_request1.metrics.update!(merged_at: merge_time)
+      merge_request2.metrics.update!(merged_at: merge_time)
+
+      average = averages.first
+      expect(average.date).to eq(merge_time.utc.to_date)
+      expect(average.average_duration_in_seconds.to_i).to eq(7.5.minutes)
+    end
+  end
+end

ee/spec/support/shared_examples/controllers/analytics/cycle_analytics/shared_stage_shared_examples.rb

@@ -264,6 +264,22 @@ RSpec.shared_examples 'Value Stream Analytics Stages controller' do
       include_examples 'Value Stream Analytics data endpoint examples'
       include_examples 'group permission check on the controller level'
     end
+
+    describe 'GET #duration_chart' do
+      subject { get :average_duration_chart, params: params }
+
+      it 'matches the response schema' do
+        fake_result = [double(MergeRequest, average_duration_in_seconds: 10, date: Time.current.to_date)]
+        expect_any_instance_of(Gitlab::Analytics::CycleAnalytics::DataForDurationChart).to receive(:average_by_day).and_return(fake_result)
+
+        subject
+
+        expect(response).to match_response_schema('analytics/cycle_analytics/average_duration_chart', dir: 'ee')
+      end
+
+      include_examples 'Value Stream Analytics data endpoint examples'
+      include_examples 'group permission check on the controller level'
+    end
   end
 end