Handle PrometheusService update in UpdateService

To be able to fully move Prometheus from Settings > Integrations to
Settings > Operations we need to extend Operations::UpdateService to
be able to update PrometheusSerive model's records

app/controllers/projects/settings/operations_controller.rb

@@ -60,7 +60,7 @@ module Projects
 
       # overridden in EE
       def permitted_project_params
-        {
+        project_params = {
           metrics_setting_attributes: [:external_dashboard_url],
 
           error_tracking_setting_attributes: [
@@ -72,6 +72,12 @@ module Projects
 
           grafana_integration_attributes: [:token, :grafana_url, :enabled]
         }
+
+        if Feature.enabled?(:settings_operations_prometheus_service, project)
+          project_params[:prometheus_integration_attributes] = [:manual_configuration, :api_url]
+        end
+
+        project_params
       end
     end
   end

app/models/project.rb

@@ -319,6 +319,7 @@ class Project < ApplicationRecord
   accepts_nested_attributes_for :error_tracking_setting, update_only: true
   accepts_nested_attributes_for :metrics_setting, update_only: true, allow_destroy: true
   accepts_nested_attributes_for :grafana_integration, update_only: true, allow_destroy: true
+  accepts_nested_attributes_for :prometheus_service, update_only: true
 
   delegate :feature_available?, :builds_enabled?, :wiki_enabled?,
     :merge_requests_enabled?, :forking_enabled?, :issues_enabled?,

app/services/projects/operations/update_service.rb

@@ -15,6 +15,7 @@ module Projects
         error_tracking_params
           .merge(metrics_setting_params)
           .merge(grafana_integration_params)
+          .merge(prometheus_integration_params)
       end
 
       def metrics_setting_params
@@ -77,6 +78,15 @@ module Projects
 
         { grafana_integration_attributes: attrs.merge(_destroy: destroy) }
       end
+
+      def prometheus_integration_params
+        return {} unless attrs = params[:prometheus_integration_attributes]
+
+        service = project.find_or_initialize_service(::PrometheusService.to_param)
+        service.assign_attributes(attrs)
+
+        { prometheus_service_attributes: service.attributes.except(*%w(id project_id created_at updated_at)) }
+      end
     end
   end
 end

spec/controllers/projects/settings/operations_controller_spec.rb

@@ -196,6 +196,39 @@ describe Projects::Settings::OperationsController do
     end
   end
 
+  context 'prometheus integration' do
+    describe 'PATCH #update' do
+      let(:params) do
+        {
+          prometheus_integration_attributes: {
+            manual_configuration: '0',
+            api_url: 'https://gitlab.prometheus.rocks'
+          }
+        }
+      end
+
+      context 'feature flag :settings_operations_prometheus_service is enabled' do
+        before do
+          stub_feature_flags(settings_operations_prometheus_service: true)
+        end
+
+        it_behaves_like 'PATCHable'
+      end
+
+      context 'feature flag :settings_operations_prometheus_service is disabled' do
+        before do
+          stub_feature_flags(settings_operations_prometheus_service: false)
+        end
+
+        it_behaves_like 'PATCHable' do
+          let(:permitted_params) do
+            ActionController::Parameters.new(params.except(:prometheus_integration_attributes)).permit!
+          end
+        end
+      end
+    end
+  end
+
   private
 
   def project_params(project, params = {})

spec/services/projects/operations/update_service_spec.rb

@@ -289,5 +289,86 @@ describe Projects::Operations::UpdateService do
         end
       end
     end
+
+    context 'prometheus integration' do
+      context 'prometheus params were passed into service' do
+        let(:prometheus_service) do
+          build_stubbed(:prometheus_service, project: project, properties: {
+            api_url: "http://example.prometheus.com",
+            manual_configuration: "0"
+          })
+        end
+        let(:prometheus_params) do
+          {
+            "type" => "PrometheusService",
+            "title" => nil,
+            "active" => true,
+            "properties" => { "api_url" => "http://example.prometheus.com", "manual_configuration" => "0" },
+            "instance" => false,
+            "push_events" => true,
+            "issues_events" => true,
+            "merge_requests_events" => true,
+            "tag_push_events" => true,
+            "note_events" => true,
+            "category" => "monitoring",
+            "default" => false,
+            "wiki_page_events" => true,
+            "pipeline_events" => true,
+            "confidential_issues_events" => true,
+            "commit_events" => true,
+            "job_events" => true,
+            "confidential_note_events" => true,
+            "deployment_events" => false,
+            "description" => nil,
+            "comment_on_event_enabled" => true
+          }
+        end
+        let(:params) do
+          {
+            prometheus_integration_attributes: {
+              api_url: 'http://new.prometheus.com',
+              manual_configuration: '1'
+            }
+          }
+        end
+
+        it 'uses Project#find_or_initialize_service to include instance defined defaults and pass them to Projects::UpdateService', :aggregate_failures do
+          project_update_service = double(Projects::UpdateService)
+          prometheus_update_params = prometheus_params.merge('properties' => {
+            'api_url' => 'http://new.prometheus.com',
+            'manual_configuration' => '1'
+          })
+
+          expect(project)
+            .to receive(:find_or_initialize_service)
+            .with('prometheus')
+            .and_return(prometheus_service)
+          expect(Projects::UpdateService)
+            .to receive(:new)
+            .with(project, user, { prometheus_service_attributes: prometheus_update_params })
+            .and_return(project_update_service)
+          expect(project_update_service).to receive(:execute)
+
+          subject.execute
+        end
+      end
+
+      context 'prometheus params were not passed into service' do
+        let(:params) { { something: :else } }
+
+        it 'does not pass any prometheus params into Projects::UpdateService', :aggregate_failures do
+          project_update_service = double(Projects::UpdateService)
+
+          expect(project).not_to receive(:find_or_initialize_service)
+          expect(Projects::UpdateService)
+            .to receive(:new)
+            .with(project, user, {})
+            .and_return(project_update_service)
+          expect(project_update_service).to receive(:execute)
+
+          subject.execute
+        end
+      end
+    end
   end
 end

spec/services/projects/update_service_spec.rb

@@ -497,6 +497,63 @@ describe Projects::UpdateService do
         update_project(project, user, { name: 'New name' })
       end
     end
+
+    context 'when updating nested attributes for prometheus service' do
+      context 'prometheus service exists' do
+        let(:prometheus_service_attributes) do
+          attributes_for(:prometheus_service,
+                         project: project,
+                         properties: { api_url: "http://new.prometheus.com", manual_configuration: "0" }
+          )
+        end
+
+        let!(:prometheus_service) do
+          create(:prometheus_service,
+                 project: project,
+                 properties: { api_url: "http://old.prometheus.com", manual_configuration: "0" }
+          )
+        end
+
+        it 'updates existing record' do
+          expect { update_project(project, user, prometheus_service_attributes: prometheus_service_attributes) }
+            .to change { prometheus_service.reload.api_url }
+            .from("http://old.prometheus.com")
+            .to("http://new.prometheus.com")
+        end
+      end
+
+      context 'prometheus service does not exist' do
+        context 'valid parameters' do
+          let(:prometheus_service_attributes) do
+            attributes_for(:prometheus_service,
+                           project: project,
+                           properties: { api_url: "http://example.prometheus.com", manual_configuration: "0" }
+            )
+          end
+
+          it 'creates new record' do
+            expect { update_project(project, user, prometheus_service_attributes: prometheus_service_attributes) }
+              .to change { ::PrometheusService.where(project: project).count }
+              .from(0)
+              .to(1)
+          end
+        end
+
+        context 'invalid parameters' do
+          let(:prometheus_service_attributes) do
+            attributes_for(:prometheus_service,
+                           project: project,
+                           properties: { api_url: nil, manual_configuration: "1" }
+            )
+          end
+
+          it 'does not create new record' do
+            expect { update_project(project, user, prometheus_service_attributes: prometheus_service_attributes) }
+              .not_to change { ::PrometheusService.where(project: project).count }
+          end
+        end
+      end
+    end
   end
 
   describe '#run_auto_devops_pipeline?' do