Introduce Pipeline abstract controller

app/controllers/projects/pipelines/application_controller.rb

+# frozen_string_literal: true
+
+# Abstract class encapsulating common logic for creating new controllers in a pipeline context
+
+module Projects
+  module Pipelines
+    class ApplicationController < Projects::ApplicationController
+      include Gitlab::Utils::StrongMemoize
+
+      before_action :pipeline
+      before_action :authorize_read_pipeline!
+
+      private
+
+      def pipeline
+        strong_memoize(:pipeline) do
+          project.all_pipelines.find(params[:pipeline_id]).tap do |pipeline|
+            render_404 unless can?(current_user, :read_pipeline, pipeline)
+          end
+        end
+      end
+    end
+  end
+end