Simplify pipelines preloader implementation

app/controllers/projects/pipelines_controller.rb

@@ -24,7 +24,7 @@ class Projects::PipelinesController < Projects::ApplicationController
     @finished_count = limited_pipelines_count(project, 'finished')
     @pipelines_count = limited_pipelines_count(project)
-    Gitlab::Ci::Pipeline::Preloader.new(@pipelines).preload!
+    Gitlab::Ci::Pipeline::Preloader.preload!(@pipelines)
     respond_to do |format|
       format.html

lib/gitlab/ci/pipeline/preloader.rb

@@ -6,46 +6,41 @@ module Gitlab
       # Class for preloading data associated with pipelines such as commit
       # authors.
       class Preloader
-        def initialize(pipelines)
-          @pipelines = pipelines
-        end
-
-        def preload!
-          @pipelines.each do |pipeline|
-            Pipeline::Preloader::Instance.new(pipeline)
-              .preload_commits
-              .preload_pipeline_warnings
-              .preload_stages_warnings
+        def self.preload!(pipelines)
+          pipelines.each do |pipeline|
+            self.new(pipeline).tap do |preloader|
+              preloader.preload_commits
+              preloader.preload_pipeline_warnings
+              preloader.preload_stages_warnings
+            end
           end
         end
-        class Instance
-          def initialize(pipeline)
-            @pipeline = pipeline
-          end
-          def preload_commits
-            # This ensures that all the pipeline commits are eager loaded before we
-            # start using them.
-            #
-            # This also preloads the author of every commit. We're using "lazy_author"
-            # here since "author" immediately loads the data on the first call.
-            tap { @pipeline.commit.try(:lazy_author) }
-          end
-          def preload_pipeline_warnings
-            # This preloads the number of warnings for every pipeline, ensuring
-            # that Ci::Pipeline#has_warnings? doesn't execute any additional
-            # queries.
-            tap { @pipeline.number_of_warnings }
-          end
-          def preload_stages_warnings
-            # This preloads the number of warnings for every stage, ensuring
-            # that Ci::Stage#has_warnings? doesn't execute any additional
-            # queries.
-            tap { @pipeline.stages.each { |stage| stage.number_of_warnings } }
-          end
+        def initialize(pipeline)
+          @pipeline = pipeline
+        end
+        def preload_commits
+          # This ensures that all the pipeline commits are eager loaded before we
+          # start using them.
+          #
+          # This also preloads the author of every commit. We're using "lazy_author"
+          # here since "author" immediately loads the data on the first call.
+          @pipeline.commit.try(:lazy_author)
+        end
+        def preload_pipeline_warnings
+          # This preloads the number of warnings for every pipeline, ensuring
+          # that Ci::Pipeline#has_warnings? doesn't execute any additional
+          # queries.
+          @pipeline.number_of_warnings
+        end
+        def preload_stages_warnings
+          # This preloads the number of warnings for every stage, ensuring
+          # that Ci::Stage#has_warnings? doesn't execute any additional
+          # queries.
+          @pipeline.stages.each { |stage| stage.number_of_warnings }
         end
       end
     end

spec/lib/gitlab/ci/pipeline/preloader_spec.rb

@@ -10,13 +10,13 @@ describe Gitlab::Ci::Pipeline::Preloader do
     double(:pipeline, commit: commit, stages: [stage])
   end
-  describe '#preload!' do
+  describe '.preload!' do
     it 'preloads commit authors and number of warnings' do
       expect(commit).to receive(:lazy_author)
       expect(pipeline).to receive(:number_of_warnings)
       expect(stage).to receive(:number_of_warnings)
-      described_class.new([pipeline]).preload!
+      described_class.preload!([pipeline])
     end
   end
 end