Include project and build ID in Pages tmp directory

This will help diagnose why some temporary paths are not being cleaned
up: https://gitlab.com/gitlab-com/gl-infra/production/-/issues/4197.

app/services/projects/update_pages_service.rb

@@ -250,13 +250,17 @@ module Projects
 
     def make_secure_tmp_dir(tmp_path)
       FileUtils.mkdir_p(tmp_path)
-      path = Dir.mktmpdir(nil, tmp_path)
+      path = Dir.mktmpdir(tmp_dir_prefix, tmp_path)
       begin
         yield(path)
       ensure
         FileUtils.remove_entry_secure(path)
       end
     end
+
+    def tmp_dir_prefix
+      "project-#{project.id}-build-#{build.id}-"
+    end
   end
 end
 

changelogs/unreleased/sh-pages-tmp-dir-use-build-id.yml

+---
+title: Include project and build ID in Pages tmp directory
+merge_request: 59106
+author:
+type: changed

spec/services/projects/update_pages_service_spec.rb

@@ -55,6 +55,12 @@ RSpec.describe Projects::UpdatePagesService do
         end
       end
 
+      it 'creates a temporary directory with the project and build ID' do
+        expect(Dir).to receive(:mktmpdir).with("project-#{project.id}-build-#{build.id}-", anything).and_call_original
+
+        subject.execute
+      end
+
       it "doesn't deploy to legacy storage if it's disabled" do
         allow(Settings.pages.local_store).to receive(:enabled).and_return(false)