Expose VSA aggregation metadata

This change exposes the value stream analytics aggregation metadata:

- Last run at
- Next run at (estimated)

app/models/analytics/cycle_analytics/aggregation.rb

@@ -10,11 +10,41 @@ class Analytics::CycleAnalytics::Aggregation < ApplicationRecord
   scope :priority_order, -> { order('last_incremental_run_at ASC NULLS FIRST') }
   scope :enabled, -> { where('enabled IS TRUE') }
 
+  def estimated_next_run_at
+    return unless enabled
+    return if last_incremental_run_at.nil?
+
+    estimation = (last_incremental_run_at - earliest_last_run_at) + average_aggregation_duration
+    estimation < 1 ? nil : estimation.from_now
+  end
+
   def self.safe_create_for_group(group)
     top_level_group = group.root_ancestor
-    return if Analytics::CycleAnalytics::Aggregation.exists?(group_id: top_level_group.id)
+    aggregation = find_by(group_id: top_level_group.id)
+    return aggregation if aggregation.present?
 
     insert({ group_id: top_level_group.id }, unique_by: :group_id)
+    find_by(group_id: top_level_group.id)
+  end
+
+  private
+
+  def average_aggregation_duration
+    return 0.seconds if incremental_runtimes_in_seconds.empty?
+
+    average = incremental_runtimes_in_seconds.sum.fdiv(incremental_runtimes_in_seconds.size)
+    average.seconds
+  end
+
+  def earliest_last_run_at
+    max = self.class.select(:last_incremental_run_at)
+      .where(enabled: true)
+      .where.not(last_incremental_run_at: nil)
+      .priority_order
+      .limit(1)
+      .to_sql
+
+    connection.select_value("(#{max})")
   end
 
   def self.load_batch(last_run_at, batch_size = 100)

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

@@ -230,4 +230,16 @@ RSpec.describe Gitlab::Analytics::CycleAnalytics::RequestParams do
       expect(data_attributes[:direction]).to eq('asc')
     end
   end
+
+  describe 'aggregation params' do
+    it 'exposes the aggregation params' do
+      data_collector_params = subject.to_data_attributes
+
+      expect(data_collector_params[:aggregation]).to eq({
+        enabled: 'true',
+        last_run_at: nil,
+        next_run_at: nil
+      })
+    end
+  end
 end

lib/gitlab/analytics/cycle_analytics/request_params.rb

@@ -86,6 +86,7 @@ module Gitlab
 
         def to_data_attributes
           {}.tap do |attrs|
+            attrs[:aggregation] = aggregation_attributes if group
             attrs[:group] = group_data_attributes if group
             attrs[:value_stream] = value_stream_data_attributes.to_json if value_stream
             attrs[:created_after] = created_after.to_date.iso8601
@@ -103,6 +104,15 @@ module Gitlab
 
         private
 
+        def aggregation_attributes
+          aggregation = ::Analytics::CycleAnalytics::Aggregation.safe_create_for_group(group)
+          {
+            enabled: aggregation.enabled.to_s,
+            last_run_at: aggregation.last_incremental_run_at,
+            next_run_at: aggregation.estimated_next_run_at
+          }
+        end
+
         def group_data_attributes
           {
             id: group.id,

spec/models/analytics/cycle_analytics/aggregation_spec.rb

@@ -25,18 +25,16 @@ RSpec.describe Analytics::CycleAnalytics::Aggregation, type: :model do
     let_it_be(:subgroup) { create(:group, parent: group) }
 
     it 'creates the aggregation record' do
-      described_class.safe_create_for_group(group)
+      record = described_class.safe_create_for_group(group)
 
-      record = described_class.find_by(group_id: group)
-      expect(record).to be_present
+      expect(record).to be_persisted
     end
 
     context 'when non top-level group is given' do
       it 'creates the aggregation record for the top-level group' do
-        described_class.safe_create_for_group(subgroup)
+        record = described_class.safe_create_for_group(subgroup)
 
-        record = described_class.find_by(group_id: group)
-        expect(record).to be_present
+        expect(record).to be_persisted
       end
     end
 
@@ -75,4 +73,56 @@ RSpec.describe Analytics::CycleAnalytics::Aggregation, type: :model do
       expect(last_two).to eq([aggregation5, aggregation2])
     end
   end
+
+  describe '#estimated_next_run_at' do
+    around do |example|
+      freeze_time { example.run }
+    end
+
+    context 'when aggregation was not yet executed for the given group' do
+      let(:aggregation) { create(:cycle_analytics_aggregation, last_incremental_run_at: nil) }
+
+      it { expect(aggregation.estimated_next_run_at).to eq(nil) }
+    end
+
+    context 'when aggregation was already run' do
+      let!(:other_aggregation1) { create(:cycle_analytics_aggregation, last_incremental_run_at: 10.minutes.ago) }
+      let!(:other_aggregation2) { create(:cycle_analytics_aggregation, last_incremental_run_at: 15.minutes.ago) }
+      let!(:aggregation) { create(:cycle_analytics_aggregation, last_incremental_run_at: 5.minutes.ago) }
+
+      it 'returns the duration between the previous run timestamp and the earliest last_incremental_run_at' do
+        expect(aggregation.estimated_next_run_at).to eq(10.minutes.from_now)
+      end
+
+      context 'when the aggregation has persisted previous runtimes' do
+        before do
+          aggregation.update!(incremental_runtimes_in_seconds: [30, 60, 90])
+        end
+
+        it 'adds the runtime to the estimation' do
+          expect(aggregation.estimated_next_run_at).to eq((10.minutes.seconds + 60.seconds).from_now)
+        end
+      end
+    end
+
+    context 'when no records are present in the DB' do
+      it 'returns nil' do
+        expect(described_class.new.estimated_next_run_at).to eq(nil)
+      end
+    end
+
+    context 'when only one aggregation record present' do
+      let!(:aggregation) { create(:cycle_analytics_aggregation, last_incremental_run_at: 5.minutes.ago) }
+
+      it 'returns nil' do
+        expect(aggregation.estimated_next_run_at).to eq(nil)
+      end
+    end
+
+    context 'when the aggregation is disabled' do
+      it 'returns nil' do
+        expect(described_class.new(enabled: false).estimated_next_run_at).to eq(nil)
+      end
+    end
+  end
 end