Use configurable page size for jobs in stages

Changelog: fixed

app/graphql/types/ci/stage_type.rb

@@ -15,10 +15,8 @@ module Types
             description: 'Group of jobs for the stage.'
       field :detailed_status, Types::Ci::DetailedStatusType, null: true,
             description: 'Detailed status of the stage.'
-      field :jobs, Ci::JobType.connection_type, null: true,
-            description: 'Jobs for the stage.',
-            method: 'latest_statuses',
-            max_page_size: 200
+      field :jobs, Types::Ci::JobType.connection_type, null: true,
+            description: 'Jobs for the stage.'
       field :status, GraphQL::Types::String,
             null: true,
             description: 'Status of the pipeline stage.'
@@ -49,6 +47,13 @@ module Types
         end
       end
 
+      def jobs
+        GraphQL::Pagination::ActiveRecordRelationConnection.new(
+          object.latest_statuses,
+          max_page_size: Gitlab::CurrentSettings.current_application_settings.jobs_per_stage_page_size
+        )
+      end
+
       private
 
       # rubocop: disable CodeReuse/ActiveRecord

app/models/application_setting.rb

@@ -207,6 +207,10 @@ class ApplicationSetting < ApplicationRecord
             numericality: { only_integer: true, greater_than_or_equal_to: 0,
                             less_than: ::Gitlab::Pages::MAX_SIZE / 1.megabyte }
 
+  validates :jobs_per_stage_page_size,
+            presence: true,
+            numericality: { only_integer: true, greater_than_or_equal_to: 0 }
+
   validates :default_artifacts_expire_in, presence: true, duration: true
 
   validates :container_expiration_policies_enable_historic_entries,

db/migrate/20210908100810_add_jobs_per_stage_page_size_to_application_settings.rb

+# frozen_string_literal: true
+
+class AddJobsPerStagePageSizeToApplicationSettings < Gitlab::Database::Migration[1.0]
+  def change
+    add_column :application_settings, :jobs_per_stage_page_size, :integer, default: 200, null: false
+  end
+end

db/schema_migrations/20210908100810

+06e45cf159cf1182b34e83f893bcff65e4722dded2bf4cbcf61fafd652158823
\ No newline at end of file

db/structure.sql

@@ -10371,6 +10371,7 @@ CREATE TABLE application_settings (
     throttle_unauthenticated_api_enabled boolean DEFAULT false NOT NULL,
     throttle_unauthenticated_api_requests_per_period integer DEFAULT 3600 NOT NULL,
     throttle_unauthenticated_api_period_in_seconds integer DEFAULT 3600 NOT NULL,
+    jobs_per_stage_page_size integer DEFAULT 200 NOT NULL,
     sidekiq_job_limiter_mode smallint DEFAULT 1 NOT NULL,
     sidekiq_job_limiter_compression_threshold_bytes integer DEFAULT 100000 NOT NULL,
     sidekiq_job_limiter_limit_bytes integer DEFAULT 0 NOT NULL,

spec/models/application_setting_spec.rb

@@ -91,6 +91,9 @@ RSpec.describe ApplicationSetting do
                        .is_less_than(::Gitlab::Pages::MAX_SIZE / 1.megabyte)
     end
 
+    it { is_expected.to validate_presence_of(:jobs_per_stage_page_size) }
+    it { is_expected.to validate_numericality_of(:jobs_per_stage_page_size).only_integer.is_greater_than_or_equal_to(0) }
+
     it { is_expected.not_to allow_value(7).for(:minimum_password_length) }
     it { is_expected.not_to allow_value(129).for(:minimum_password_length) }
     it { is_expected.not_to allow_value(nil).for(:minimum_password_length) }

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

@@ -4,11 +4,13 @@ require 'spec_helper'
 RSpec.describe 'Query.project.pipeline.stages' do
   include GraphqlHelpers
 
-  let(:project) { create(:project, :repository, :public) }
-  let(:user) { create(:user) }
-  let(:pipeline) { create(:ci_pipeline, project: project, user: user) }
-  let(:stage_graphql_data) { graphql_data['project']['pipeline']['stages'] }
+  subject(:post_query) { post_graphql(query, current_user: user) }
 
+  let_it_be(:project) { create(:project, :repository, :public) }
+  let_it_be(:user) { create(:user) }
+  let_it_be(:pipeline) { create(:ci_pipeline, project: project, user: user) }
+
+  let(:stage_nodes) { graphql_data_at(:project, :pipeline, :stages, :nodes) }
   let(:params) { {} }
 
   let(:fields) do
@@ -33,14 +35,42 @@ RSpec.describe 'Query.project.pipeline.stages' do
     )
   end
 
-  before do
+  before_all do
     create(:ci_stage_entity, pipeline: pipeline, name: 'deploy')
-    post_graphql(query, current_user: user)
+    create_list(:ci_build, 2, pipeline: pipeline, stage: 'deploy')
   end
 
-  it_behaves_like 'a working graphql query'
+  it_behaves_like 'a working graphql query' do
+    before do
+      post_query
+    end
+  end
 
   it 'returns the stage of a pipeline' do
-    expect(stage_graphql_data['nodes'].first['name']).to eq('deploy')
+    post_query
+
+    expect(stage_nodes.first['name']).to eq('deploy')
+  end
+
+  describe 'job pagination' do
+    let(:job_nodes) { graphql_dig_at(stage_nodes, :jobs, :nodes) }
+
+    it 'returns up to default limit jobs per stage' do
+      post_query
+
+      expect(job_nodes.count).to eq(2)
+    end
+
+    context 'when the limit is manually set' do
+      before do
+        stub_application_setting(jobs_per_stage_page_size: 1)
+      end
+
+      it 'returns up to custom limit jobs per stage' do
+        post_query
+
+        expect(job_nodes.count).to eq(1)
+      end
+    end
   end
 end