Add jobCount and projectCount to GraphQL CiRunner

https://gitlab.com/gitlab-org/gitlab/-/issues/332345
https://gitlab.com/gitlab-org/gitlab/-/merge_requests/64117

Changelog: added

app/graphql/types/ci/runner_type.rb

@@ -6,6 +6,10 @@ module Types
       graphql_name 'CiRunner'
       authorize :read_runner
 
+      JOB_COUNT_LIMIT = 1000
+
+      alias_method :runner, :object
+
       field :id, ::Types::GlobalIDType[::Ci::Runner], null: false,
             description: 'ID of the runner.'
       field :description, GraphQL::STRING_TYPE, null: true,
@@ -37,6 +41,30 @@ module Types
             description: 'Type of the runner.'
       field :tag_list, [GraphQL::STRING_TYPE], null: true,
             description: 'Tags associated with the runner.'
+      field :project_count, GraphQL::INT_TYPE, null: true,
+            description: 'Number of projects that the runner is associated with.'
+      field :job_count, GraphQL::INT_TYPE, null: true,
+            description: "Number of jobs processed by the runner (limited to #{JOB_COUNT_LIMIT}, plus one to indicate that more items exist)."
+
+      def job_count
+        # We limit to 1 above the JOB_COUNT_LIMIT to indicate that more items exist after JOB_COUNT_LIMIT
+        runner.builds.limit(JOB_COUNT_LIMIT + 1).count
+      end
+
+      # rubocop: disable CodeReuse/ActiveRecord
+      def project_count
+        BatchLoader::GraphQL.for(runner.id).batch(key: :runner_project_count) do |ids, loader, args|
+          counts = ::Ci::RunnerProject.select(:runner_id, 'COUNT(*) as count')
+            .where(runner_id: ids)
+            .group(:runner_id)
+            .index_by(&:runner_id)
+
+          ids.each do |id|
+            loader.call(id, counts[id]&.count)
+          end
+        end
+      end
+      # rubocop: enable CodeReuse/ActiveRecord
     end
   end
 end

doc/api/graphql/reference/index.md

@@ -7710,9 +7710,11 @@ Represents the total number of issues and their weights for a particular day.
 | <a id="cirunnerdescription"></a>`description` | [`String`](#string) | Description of the runner. |
 | <a id="cirunnerid"></a>`id` | [`CiRunnerID!`](#cirunnerid) | ID of the runner. |
 | <a id="cirunneripaddress"></a>`ipAddress` | [`String!`](#string) | IP address of the runner. |
+| <a id="cirunnerjobcount"></a>`jobCount` | [`Int`](#int) | Number of jobs processed by the runner (limited to 1000, plus one to indicate that more items exist). |
 | <a id="cirunnerlocked"></a>`locked` | [`Boolean`](#boolean) | Indicates the runner is locked. |
 | <a id="cirunnermaximumtimeout"></a>`maximumTimeout` | [`Int`](#int) | Maximum timeout (in seconds) for jobs processed by the runner. |
 | <a id="cirunnerprivateprojectsminutescostfactor"></a>`privateProjectsMinutesCostFactor` | [`Float`](#float) | Private projects' "minutes cost factor" associated with the runner (GitLab.com only). |
+| <a id="cirunnerprojectcount"></a>`projectCount` | [`Int`](#int) | Number of projects that the runner is associated with. |
 | <a id="cirunnerpublicprojectsminutescostfactor"></a>`publicProjectsMinutesCostFactor` | [`Float`](#float) | Public projects' "minutes cost factor" associated with the runner (GitLab.com only). |
 | <a id="cirunnerrevision"></a>`revision` | [`String!`](#string) | Revision of the runner. |
 | <a id="cirunnerrununtagged"></a>`runUntagged` | [`Boolean!`](#boolean) | Indicates the runner is able to run untagged jobs. |

spec/graphql/types/ci/runner_type_spec.rb

@@ -11,6 +11,7 @@ RSpec.describe GitlabSchema.types['CiRunner'] do
     expected_fields = %w[
       id description contacted_at maximum_timeout access_level active status
       version short_sha revision locked run_untagged ip_address runner_type tag_list
+      project_count job_count
     ]
 
     expect(described_class).to include_graphql_fields(*expected_fields)

spec/requests/api/graphql/ci/runner_spec.rb

@@ -59,7 +59,9 @@ RSpec.describe 'Query.runner(id)' do
         'accessLevel' => runner.access_level.to_s.upcase,
         'runUntagged' => runner.run_untagged,
         'ipAddress' => runner.ip_address,
-        'runnerType' => 'INSTANCE_TYPE'
+        'runnerType' => 'INSTANCE_TYPE',
+        'jobCount' => 0,
+        'projectCount' => nil
       )
       expect(runner_data['tagList']).to match_array runner.tag_list
     end
@@ -111,6 +113,51 @@ RSpec.describe 'Query.runner(id)' do
     it_behaves_like 'runner details fetch', :inactive_runner
   end
 
+  describe 'for multiple runners' do
+    let_it_be(:project1) { create(:project, :test_repo) }
+    let_it_be(:project2) { create(:project, :test_repo) }
+    let_it_be(:project_runner) do
+      create(:ci_runner, :project, projects: [project1, project2], description: 'Runner 1', contacted_at: 2.hours.ago,
+             active: true, version: 'adfe156', revision: 'a', locked: true, ip_address: '127.0.0.1', maximum_timeout: 600,
+             access_level: 0, run_untagged: true)
+    end
+
+    let!(:job) { create(:ci_build, runner: project_runner) }
+
+    context 'requesting project and job counts' do
+      let(:query) do
+        %(
+          query {
+            projectRunner: runner(id: "#{project_runner.to_global_id}") {
+              projectCount
+              jobCount
+            }
+            activeRunner: runner(id: "#{active_runner.to_global_id}") {
+              projectCount
+              jobCount
+            }
+          }
+        )
+      end
+
+      before do
+        post_graphql(query, current_user: user)
+      end
+
+      it 'retrieves expected fields' do
+        runner1_data = graphql_data_at(:project_runner)
+        runner2_data = graphql_data_at(:active_runner)
+
+        expect(runner1_data).to match a_hash_including(
+          'jobCount' => 1,
+          'projectCount' => 2)
+        expect(runner2_data).to match a_hash_including(
+          'jobCount' => 0,
+          'projectCount' => nil)
+      end
+    end
+  end
+
   describe 'by regular user' do
     let(:user) { create_default(:user) }
 
@@ -127,11 +174,14 @@ RSpec.describe 'Query.runner(id)' do
     def runner_query(runner)
       <<~SINGLE
         runner(id: "#{runner.to_global_id}") {
-          #{all_graphql_fields_for('CiRunner')}
+          #{all_graphql_fields_for('CiRunner', excluded: excluded_fields)}
         }
       SINGLE
     end
 
+    # Currently excluding a known N+1 issue, see https://gitlab.com/gitlab-org/gitlab/-/issues/334759
+    let(:excluded_fields) { %w[jobCount] }
+
     let(:single_query) do
       <<~QUERY
         {