Add projects_with_sectional_code_owner_rules to usage_data

We want to be able to answer how many projects are using sectional
codeowners feature.

db/post_migrate/20200817100710_add_section_and_created_at_codeowner_approval_merge_request_index.rb

+# frozen_string_literal: true
+
+class AddSectionAndCreatedAtCodeownerApprovalMergeRequestIndex < ActiveRecord::Migration[6.0]
+  include Gitlab::Database::MigrationHelpers
+
+  DOWNTIME = false
+  SECTION_CREATED_AT_ON_CODEOWNER_APPROVAL_MERGE_REQUEST_RULES = "index_created_at_on_codeowner_approval_merge_request_rules"
+  RULE_TYPE_CODEOWNERS = 2
+  CODEOWNER_SECTION_DEFAULT = 'codeowners'
+
+  disable_ddl_transaction!
+
+  def up
+    add_concurrent_index :approval_merge_request_rules, :created_at,
+      where: "rule_type = #{RULE_TYPE_CODEOWNERS} AND section != '#{CODEOWNER_SECTION_DEFAULT}'::text",
+      name: SECTION_CREATED_AT_ON_CODEOWNER_APPROVAL_MERGE_REQUEST_RULES
+  end
+
+  def down
+    remove_concurrent_index_by_name :approval_merge_request_rules, SECTION_CREATED_AT_ON_CODEOWNER_APPROVAL_MERGE_REQUEST_RULES
+  end
+end

db/schema_migrations/20200817100710

+87d3529596f5b5adff7280be7c60e4ff290dd05c500bbeb00cda0ac5da6239e0
\ No newline at end of file

db/structure.sql

@@ -19455,6 +19455,8 @@ CREATE UNIQUE INDEX index_container_repositories_on_project_id_and_name ON publi
 
 CREATE INDEX index_container_repository_on_name_trigram ON public.container_repositories USING gin (name public.gin_trgm_ops);
 
+CREATE INDEX index_created_at_on_codeowner_approval_merge_request_rules ON public.approval_merge_request_rules USING btree (created_at) WHERE ((rule_type = 2) AND (section <> 'codeowners'::text));
+
 CREATE UNIQUE INDEX index_custom_emoji_on_namespace_id_and_name ON public.custom_emoji USING btree (namespace_id, name);
 
 CREATE UNIQUE INDEX index_daily_build_group_report_results_unique_columns ON public.ci_daily_build_group_report_results USING btree (project_id, ref_path, date, group_name);

ee/changelogs/unreleased/227429-add-codeowners-to-usage-data.yml

+---
+title: Add usage data for counting projects with sectional codeowner rules
+merge_request: 37786
+author:
+type: added

ee/lib/ee/gitlab/usage_data.rb

@@ -219,6 +219,7 @@ module EE
         def usage_activity_by_stage_create(time_period)
           super.merge({
             projects_enforcing_code_owner_approval: distinct_count(::Project.requiring_code_owner_approval.where(time_period), :creator_id),
+            projects_with_sectional_code_owner_rules: projects_with_sectional_code_owner_rules(time_period),
             merge_requests_with_added_rules: distinct_count(::ApprovalMergeRequestRule.where(time_period).with_added_approval_rules,
                                                             :merge_request_id,
                                                             start: approval_merge_request_rule_minimum_id,
@@ -390,6 +391,23 @@ module EE
           count(::JiraService.active.includes(:jira_tracker_data).where(jira_tracker_data: { issues_enabled: true }), start: min_id, finish: max_id)
         end
         # rubocop:enable CodeReuse/ActiveRecord
+
+        # rubocop:disable CodeReuse/ActiveRecord
+        # rubocop: disable UsageData/DistinctCountByLargeForeignKey
+        def projects_with_sectional_code_owner_rules(time_period)
+          distinct_count(
+            ::ApprovalMergeRequestRule
+              .code_owner
+              .joins(:merge_request)
+              .where("section != ?", ::Gitlab::CodeOwners::Entry::DEFAULT_SECTION)
+              .where(time_period),
+            'merge_requests.target_project_id',
+            start: project_minimum_id,
+            finish: project_maximum_id
+          )
+        end
+        # rubocop: enable UsageData/DistinctCountByLargeForeignKey
+        # rubocop:enable CodeReuse/ActiveRecord
       end
     end
   end

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

@@ -315,7 +315,7 @@ RSpec.describe Gitlab::UsageData do
         create(:approval_project_rule, protected_branches: [protected_branch], project: project)
         create(:suggestion, note: create(:note, project: project))
         create(:code_owner_rule, merge_request: merge_request, approvals_required: 3)
-        create(:code_owner_rule, merge_request: merge_request, approvals_required: 7)
+        create(:code_owner_rule, merge_request: merge_request, approvals_required: 7, section: 'new_section')
         create(:approval_merge_request_rule, merge_request: merge_request)
         create_list(:code_owner_rule, 3, approvals_required: 2)
         create_list(:code_owner_rule, 2)
@@ -325,6 +325,7 @@ RSpec.describe Gitlab::UsageData do
         approval_project_rules: 6,
         approval_project_rules_with_target_branch: 2,
         projects_enforcing_code_owner_approval: 0,
+        projects_with_sectional_code_owner_rules: 2,
         merge_requests_with_added_rules: 12,
         merge_requests_with_optional_codeowners: 4,
         merge_requests_with_required_codeowners: 8,
@@ -337,6 +338,7 @@ RSpec.describe Gitlab::UsageData do
         approval_project_rules: 6,
         approval_project_rules_with_target_branch: 2,
         projects_enforcing_code_owner_approval: 0,
+        projects_with_sectional_code_owner_rules: 1,
         merge_requests_with_added_rules: 6,
         merge_requests_with_optional_codeowners: 2,
         merge_requests_with_required_codeowners: 4,

lib/gitlab/usage_data.rb

@@ -716,6 +716,18 @@ module Gitlab
         end
       end
 
+      def project_minimum_id
+        strong_memoize(:project_minimum_id) do
+          ::Project.minimum(:id)
+        end
+      end
+
+      def project_maximum_id
+        strong_memoize(:project_maximum_id) do
+          ::Project.maximum(:id)
+        end
+      end
+
       def clear_memoized
         clear_memoization(:issue_minimum_id)
         clear_memoization(:issue_maximum_id)
@@ -726,6 +738,8 @@ module Gitlab
         clear_memoization(:deployment_maximum_id)
         clear_memoization(:approval_merge_request_rule_minimum_id)
         clear_memoization(:approval_merge_request_rule_maximum_id)
+        clear_memoization(:project_minimum_id)
+        clear_memoization(:project_maximum_id)
       end
 
       # rubocop: disable CodeReuse/ActiveRecord

spec/lib/gitlab/usage_data_spec.rb

@@ -25,6 +25,7 @@ RSpec.describe Gitlab::UsageData, :aggregate_failures do
 
       it 'clears memoized values' do
         values = %i(issue_minimum_id issue_maximum_id
+                    project_minimum_id project_maximum_id
                     user_minimum_id user_maximum_id unique_visit_service
                     deployment_minimum_id deployment_maximum_id
                     approval_merge_request_rule_minimum_id