Implement duration_chart endpoint in CA

- Expose `duration_chart` endpoint
- Implement query to get the duration and finish time
- Allow `project_ids` url parameter to be passed
(already handled in the query)

app/controllers/concerns/cycle_analytics_params.rb

@@ -38,7 +38,8 @@ module CycleAnalyticsParams
   end
 
   def to_utc_time(field)
-    Date.parse(field).to_time.utc
+    date = field.is_a?(Date) ? field : Date.parse(field)
+    date.to_time.utc
   end
 end
 

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

@@ -6,7 +6,7 @@ module Analytics
       check_feature_flag Gitlab::Analytics::CYCLE_ANALYTICS_FEATURE_FLAG
 
       before_action :load_group
-      before_action :validate_params, only: %i[median records]
+      before_action :validate_params, only: %i[median records duration_chart]
 
       def index
         return render_403 unless can?(current_user, :read_group_cycle_analytics, @group)
@@ -50,6 +50,12 @@ module Analytics
         render json: data_collector.serialized_records
       end
 
+      def duration_chart
+        return render_403 unless can?(current_user, :read_group_stage, @group)
+
+        render json: Analytics::CycleAnalytics::DurationChartItemEntity.represent(data_collector.duration_chart_data)
+      end
+
       private
 
       def validate_params
@@ -62,14 +68,15 @@ module Analytics
       end
 
       def request_params
-        @request_params ||= Gitlab::Analytics::CycleAnalytics::RequestParams.new(params.permit(:created_before, :created_after))
+        @request_params ||= Gitlab::Analytics::CycleAnalytics::RequestParams.new(data_collector_params)
       end
 
       def data_collector
         @data_collector ||= Gitlab::Analytics::CycleAnalytics::DataCollector.new(stage: stage, params: {
           current_user: current_user,
           from: request_params.created_after,
-          to: request_params.created_before
+          to: request_params.created_before,
+          project_ids: request_params.project_ids
         })
       end
 
@@ -108,6 +115,10 @@ module Analytics
         end
       end
 
+      def data_collector_params
+        params.permit(:created_before, :created_after, project_ids: [])
+      end
+
       def update_params
         params.permit(:name, :start_event_identifier, :end_event_identifier, :id, :move_after_id, :move_before_id, :hidden)
       end

ee/app/controllers/analytics/cycle_analytics/summary_controller.rb

@@ -13,15 +13,19 @@ module Analytics
       def show
         return render_403 unless can?(current_user, :read_group_cycle_analytics, @group)
 
-        group_level = ::CycleAnalytics::GroupLevel.new(group: @group, options: options(allowed_group_params))
+        group_level = ::CycleAnalytics::GroupLevel.new(group: @group, options: options(group_params))
 
         render json: group_level.summary
       end
 
       private
 
-      def allowed_group_params
-        params.permit(:created_after, :created_before, project_ids: [])
+      def group_params
+        {
+          created_after: request_params.created_after,
+          created_before: request_params.created_before,
+          project_ids: request_params.project_ids
+        }
       end
 
       def validate_params
@@ -34,7 +38,11 @@ module Analytics
       end
 
       def request_params
-        @request_params ||= Gitlab::Analytics::CycleAnalytics::RequestParams.new(params.permit(:created_before, :created_after))
+        @request_params ||= Gitlab::Analytics::CycleAnalytics::RequestParams.new(allowed_params)
+      end
+
+      def allowed_params
+        params.permit(:created_after, :created_before, project_ids: [])
       end
     end
   end

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

+# frozen_string_literal: true
+
+module Analytics
+  module CycleAnalytics
+    class DurationChartItemEntity < Grape::Entity
+      expose :finished_at
+      expose :duration_in_seconds
+    end
+  end
+end

ee/config/routes/analytics.rb

@@ -10,6 +10,7 @@ namespace :analytics do
     namespace :cycle_analytics do
       resources :stages, only: [:index, :create, :update, :destroy] do
         member do
+          get :duration_chart
           get :median
           get :records
         end

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

+# frozen_string_literal: true
+
+module EE
+  module Gitlab
+    module Analytics
+      module CycleAnalytics
+        module DataCollector
+          def duration_chart_data
+            strong_memoize(:duration_chart) do
+              ::Gitlab::Analytics::CycleAnalytics::DataForDurationChart.new(stage: stage, query: query).load
+            end
+          end
+        end
+      end
+    end
+  end
+end

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

+# frozen_string_literal: true
+
+module Gitlab
+  module Analytics
+    module CycleAnalytics
+      class DataForDurationChart
+        include StageQueryHelpers
+
+        MAX_RESULTS = 500
+
+        def initialize(stage:, query:)
+          @stage = stage
+          @query = query
+        end
+
+        # rubocop: disable CodeReuse/ActiveRecord
+        def load
+          query
+            .select(round_duration_to_seconds.as('duration_in_seconds'), stage.end_event.timestamp_projection.as('finished_at'))
+            .reorder(stage.end_event.timestamp_projection.desc)
+            .limit(MAX_RESULTS)
+        end
+        # rubocop: enable CodeReuse/ActiveRecord
+
+        private
+
+        attr_reader :stage, :query
+      end
+    end
+  end
+end

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

@@ -8,6 +8,8 @@ module Gitlab
         include ActiveModel::Validations
         include ActiveModel::Attributes
 
+        attr_writer :project_ids
+
         attribute :created_after, :date
         attribute :created_before, :date
 
@@ -16,6 +18,10 @@ module Gitlab
 
         validate :validate_created_before
 
+        def project_ids
+          Array(@project_ids)
+        end
+
         private
 
         def validate_created_before

ee/spec/controllers/analytics/cycle_analytics/stages_controller_spec.rb

@@ -185,43 +185,48 @@ describe Analytics::CycleAnalytics::StagesController do
         expect(response).to have_gitlab_http_status(:forbidden)
       end
     end
+  end
+
+  describe 'data endpoints' do
+    let(:stage) { create(:cycle_analytics_group_stage, parent: group) }
+
+    before do
+      params[:id] = stage.id
+    end
 
     describe 'GET `median`' do
       subject { get :median, params: params }
 
-      before do
-        params[:created_after] = '2019-01-01'
-        params[:created_before] = '2020-01-01'
-      end
-
-      it 'succeeds' do
+      it 'matches the response schema' do
         subject
 
-        expect(response).to be_successful
         expect(response).to match_response_schema('analytics/cycle_analytics/median', dir: 'ee')
       end
 
-      include_examples 'date parameter examples'
-
+      include_examples 'cycle analytics data endpoint examples'
       include_examples 'group permission check on the controller level'
     end
 
     describe 'GET `records`' do
       subject { get :records, params: params }
 
-      before do
-        params[:created_after] = '2019-01-01'
-        params[:created_before] = '2020-01-01'
-      end
+      include_examples 'cycle analytics data endpoint examples'
+      include_examples 'group permission check on the controller level'
+    end
+
+    describe 'GET `duration_chart`' do
+      subject { get :duration_chart, params: params }
+
+      it 'matches the response schema' do
+        fake_result = [double(MergeRequest, duration_in_seconds: 10, finished_at: Time.now)]
+        expect_any_instance_of(Gitlab::Analytics::CycleAnalytics::DataForDurationChart).to receive(:load).and_return(fake_result)
 
-      it 'succeeds' do
         subject
 
-        expect(response).to be_successful
+        expect(response).to match_response_schema('analytics/cycle_analytics/duration_chart', dir: 'ee')
       end
 
-      include_examples 'date parameter examples'
-
+      include_examples 'cycle analytics data endpoint examples'
       include_examples 'group permission check on the controller level'
     end
   end

ee/spec/controllers/analytics/cycle_analytics/summary_controller_spec.rb

@@ -25,8 +25,7 @@ describe Analytics::CycleAnalytics::SummaryController do
       expect(response).to match_response_schema('analytics/cycle_analytics/summary', dir: 'ee')
     end
 
-    include_examples 'date parameter examples'
-
+    include_examples 'cycle analytics data endpoint examples'
     include_examples 'group permission check on the controller level'
   end
 end

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

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

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

@@ -58,6 +58,16 @@ describe Gitlab::Analytics::CycleAnalytics::DataCollector do
     it 'calculates median' do
       expect(round_to_days(data_collector.median.seconds)).to eq(10)
     end
+
+    describe '#duration_chart_data' do
+      subject { data_collector.duration_chart_data }
+
+      it 'loads data ordered by event time' do
+        days = subject.map { |item| round_to_days(item.duration_in_seconds) }
+
+        expect(days).to eq([15, 10, 5])
+      end
+    end
   end
 
   shared_examples 'test various start and end event combinations' do

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

@@ -40,4 +40,34 @@ describe Gitlab::Analytics::CycleAnalytics::RequestParams do
   it 'casts `created_before` to date' do
     expect(subject.created_before).to be_a_kind_of(Date)
   end
+
+  describe 'optional `project_ids`' do
+    it { expect(subject.project_ids).to eq([]) }
+
+    context 'when `project_ids` is not empty' do
+      let(:project_ids) { [1, 2, 3] }
+
+      before do
+        params[:project_ids] = project_ids
+      end
+
+      it { expect(subject.project_ids).to eq(project_ids) }
+    end
+
+    context 'when `project_ids` is not an array' do
+      before do
+        params[:project_ids] = 1
+      end
+
+      it { expect(subject.project_ids).to eq([1]) }
+    end
+
+    context 'when `project_ids` is nil' do
+      before do
+        params[:project_ids] = nil
+      end
+
+      it { expect(subject.project_ids).to eq([]) }
+    end
+  end
 end

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

@@ -78,7 +78,7 @@ shared_context 'when invalid stage parameters are given' do
   end
 end
 
-shared_examples 'date parameter examples' do
+shared_examples 'cycle analytics data endpoint examples' do
   before do
     params[:created_after] = '2019-01-01'
     params[:created_before] = '2020-01-01'
@@ -92,6 +92,20 @@ shared_examples 'date parameter examples' do
     end
   end
 
+  context 'accepts optional `project_ids` array' do
+    before do
+      params[:project_ids] = [1, 2, 3]
+    end
+
+    it 'succeeds' do
+      expect_any_instance_of(Gitlab::Analytics::CycleAnalytics::RequestParams).to receive(:project_ids=).with(%w[1 2 3]).and_call_original
+
+      subject
+
+      expect(response).to be_successful
+    end
+  end
+
   shared_examples 'example for invalid parameter' do
     it 'renders `unprocessable_entity`' do
       subject

lib/gitlab/analytics/cycle_analytics/data_collector.rb

@@ -42,3 +42,5 @@ module Gitlab
     end
   end
 end
+
+Gitlab::Analytics::CycleAnalytics::DataCollector.prepend_if_ee('EE::Gitlab::Analytics::CycleAnalytics::DataCollector')

lib/gitlab/analytics/cycle_analytics/stage_query_helpers.rb

@@ -9,11 +9,11 @@ module Gitlab
         end
 
         def zero_interval
-          Arel::Nodes::NamedFunction.new("CAST", [Arel.sql("'0' AS INTERVAL")])
+          Arel::Nodes::NamedFunction.new('CAST', [Arel.sql("'0' AS INTERVAL")])
         end
 
         def round_duration_to_seconds
-          Arel::Nodes::Extract.new(duration, :epoch)
+          Arel::Nodes::NamedFunction.new('ROUND', [Arel::Nodes::Extract.new(duration, :epoch)])
         end
 
         def duration