Reduce SQL requests on building artifacts

When we serialize downloadable artifacts for a
pipeline, we fetch project via artifacts' association.
It produces a lot of CACHE requests. Let's eliminate
them by passing project to the serializer explicitly

app/serializers/build_artifact_entity.rb

@@ -15,18 +15,18 @@ class BuildArtifactEntity < Grape::Entity
 
   expose :path do |artifact|
     fast_download_project_job_artifacts_path(
-      artifact.project,
+      project,
       artifact.job,
       file_type: artifact.file_type
     )
   end
 
-  expose :keep_path, if: -> (*) { artifact.expiring? && show_duplicated_paths?(artifact.project) } do |artifact|
-    fast_keep_project_job_artifacts_path(artifact.project, artifact.job)
+  expose :keep_path, if: -> (*) { artifact.expiring? && show_duplicated_paths?(project) } do |artifact|
+    fast_keep_project_job_artifacts_path(project, artifact.job)
   end
 
-  expose :browse_path, if: -> (*) { show_duplicated_paths?(artifact.project) } do |artifact|
-    fast_browse_project_job_artifacts_path(artifact.project, artifact.job)
+  expose :browse_path, if: -> (*) { show_duplicated_paths?(project) } do |artifact|
+    fast_browse_project_job_artifacts_path(project, artifact.job)
   end
 
   private
@@ -34,4 +34,8 @@ class BuildArtifactEntity < Grape::Entity
   def show_duplicated_paths?(project)
     !Gitlab::Ci::Features.remove_duplicate_artifact_exposure_paths?(project)
   end
+
+  def project
+    options[:project] || artifact.project
+  end
 end

app/serializers/merge_requests/pipeline_entity.rb

@@ -28,7 +28,7 @@ class MergeRequests::PipelineEntity < Grape::Entity
         rel = rel.select { |artifact| can?(request.current_user, :read_job_artifacts, artifact.job) }
       end
 
-      BuildArtifactEntity.represent(rel, options)
+      BuildArtifactEntity.represent(rel, options.merge(project: pipeline.project))
     end
 
     expose :detailed_status, as: :status, with: DetailedStatusEntity do |pipeline|

app/serializers/pipeline_details_entity.rb

@@ -15,7 +15,7 @@ class PipelineDetailsEntity < Ci::PipelineEntity
         rel = rel.select { |artifact| can?(request.current_user, :read_job_artifacts, artifact.job) }
       end
 
-      BuildArtifactEntity.represent(rel, options)
+      BuildArtifactEntity.represent(rel, options.merge(project: pipeline.project))
     end
     expose :manual_actions, using: BuildActionEntity
     expose :scheduled_actions, using: BuildActionEntity

changelogs/unreleased/id-reduce-cached-requests.yml

+---
+title: Reduce SQL requests on building artifacts
+merge_request: 58339
+author:
+type: performance

spec/serializers/build_artifact_entity_spec.rb

@@ -3,11 +3,13 @@
 require 'spec_helper'
 
 RSpec.describe BuildArtifactEntity do
-  let(:job) { create(:ci_build) }
-  let(:artifact) { create(:ci_job_artifact, :codequality, expire_at: 1.hour.from_now, job: job) }
+  let_it_be(:job) { create(:ci_build) }
+  let_it_be(:artifact) { create(:ci_job_artifact, :codequality, expire_at: 1.hour.from_now, job: job) }
+
+  let(:options) { { request: double } }
 
   let(:entity) do
-    described_class.new(artifact, request: double)
+    described_class.represent(artifact, options)
   end
 
   describe '#as_json' do
@@ -46,5 +48,15 @@ RSpec.describe BuildArtifactEntity do
         expect(subject[:browse_path]).to be_present
       end
     end
+
+    context 'when project is specified in options' do
+      let(:options) { super().merge(project: job.project) }
+
+      it 'doesnt get a project from the artifact' do
+        expect(artifact).not_to receive(:project)
+
+        subject
+      end
+    end
   end
 end