Only update pages config if pages are deployed

The pages config is a file inside the path on the shared NFS. The
directory into which this file is written is created when pages are
deployed and the artifacts are extracted.

If this path has been removed, or hasn't been created yet, we don't
need to update configuration.

Updating the configuration is also a step in the deployment of
pages. So the first deploy, the configuration would be written.

app/services/projects/update_pages_configuration_service.rb

@@ -11,6 +11,11 @@ module Projects
     end
 
     def execute
+      # If the pages were never deployed, we can't write out the config, as the
+      # directory would not exist.
+      # https://gitlab.com/gitlab-org/gitlab/-/issues/235139
+      return success unless project.pages_deployed?
+
       unless file_equals?(pages_config_file, pages_config_json)
         update_file(pages_config_file, pages_config_json)
         reload_daemon

app/services/projects/update_service.rb

@@ -142,6 +142,8 @@ module Projects
     end
 
     def update_pages_config
+      return unless project.pages_deployed?
+
       if Feature.enabled?(:async_update_pages_config, project)
         PagesUpdateConfigurationWorker.perform_async(project.id)
       else

spec/services/projects/update_pages_configuration_service_spec.rb

@@ -3,25 +3,33 @@
 require 'spec_helper'
 
 RSpec.describe Projects::UpdatePagesConfigurationService do
-  let(:project) { create(:project) }
   let(:service) { described_class.new(project) }
 
   describe "#execute" do
-    let(:file) { Tempfile.new('pages-test') }
-
     subject { service.execute }
 
-    after do
-      file.close
-      file.unlink
+    context 'when pages are deployed' do
+      let_it_be(:project) do
+        create(:project).tap(&:mark_pages_as_deployed)
       end
 
+      let(:file) { Tempfile.new('pages-test') }
+
       before do
         allow(service).to receive(:pages_config_file).and_return(file.path)
       end
 
+      after do
+        file.close
+        file.unlink
+      end
+
       context 'when configuration changes' do
-      it 'updates the .update file' do
+        it 'updates the config and reloads the daemon' do
+          allow(service).to receive(:update_file).and_call_original
+
+          expect(service).to receive(:update_file).with(file.path, an_instance_of(String))
+            .and_call_original
           expect(service).to receive(:reload_daemon).and_call_original
 
           expect(subject).to include(status: :success)
@@ -50,4 +58,21 @@ RSpec.describe Projects::UpdatePagesConfigurationService do
         end
       end
     end
+
+    context 'when pages are not deployed' do
+      let_it_be(:project) do
+        create(:project).tap(&:mark_pages_as_not_deployed)
+      end
+
+      it 'returns successfully' do
+        expect(subject).to eq(status: :success)
+      end
+
+      it 'does not update the config' do
+        expect(service).not_to receive(:update_file)
+
+        subject
+      end
+    end
+  end
 end

spec/services/projects/update_service_spec.rb

@@ -397,18 +397,30 @@ RSpec.describe Projects::UpdateService do
     end
 
     shared_examples 'updating pages configuration' do
-      it 'schedules the `PagesUpdateConfigurationWorker`' do
+      it 'schedules the `PagesUpdateConfigurationWorker` when pages are deployed' do
+        project.mark_pages_as_deployed
+
         expect(PagesUpdateConfigurationWorker).to receive(:perform_async).with(project.id)
 
         subject
       end
 
+      it "does not schedule a job when pages aren't deployed" do
+        project.mark_pages_as_not_deployed
+
+        expect(PagesUpdateConfigurationWorker).not_to receive(:perform_async).with(project.id)
+
+        subject
+      end
+
       context 'when `async_update_pages_config` is disabled' do
         before do
           stub_feature_flags(async_update_pages_config: false)
         end
 
-        it 'calls Projects::UpdatePagesConfigurationService' do
+        it 'calls Projects::UpdatePagesConfigurationService when pages are deployed' do
+          project.mark_pages_as_deployed
+
           expect(Projects::UpdatePagesConfigurationService)
             .to receive(:new)
                   .with(project)
@@ -416,6 +428,15 @@ RSpec.describe Projects::UpdateService do
 
           subject
         end
+
+        it "does not update pages config when pages aren't deployed" do
+          project.mark_pages_as_not_deployed
+
+          expect(Projects::UpdatePagesConfigurationService)
+            .not_to receive(:new)
+
+          subject
+        end
       end
     end