Implement POC for job parallelization

lib/gitlab/ci/pipeline/seed/build.rb

@@ -24,6 +24,24 @@ module Gitlab
             end
           end
 
+          def parallelized?
+            @attributes[:options].include?(:parallel)
+          end
+
+          def parallelize_build
+            builds = []
+
+            total = @attributes[:options][:parallel]
+
+            total.times do |i|
+              build = ::Ci::Build.new(attributes.merge(options: { variables: { CI_NODE_INDEX: i + 1, CI_NODE_TOTAL: total } }))
+              build.name = build.name + "_#{i + 1}/#{total}"
+              builds << build
+            end
+
+            builds
+          end
+
           def attributes
             @attributes.merge(
               pipeline: @pipeline,
@@ -38,7 +56,11 @@ module Gitlab
 
           def to_resource
             strong_memoize(:resource) do
-              ::Ci::Build.new(attributes)
+              if parallelized?
+                parallelize_build
+              else
+                ::Ci::Build.new(attributes)
+              end
             end
           end
         end

lib/gitlab/ci/yaml_processor.rb

@@ -50,6 +50,7 @@ module Gitlab
             after_script: job[:after_script],
             environment: job[:environment],
             retry: job[:retry],
+            parallel: job[:parallel],
             start_in: job[:start_in]
           }.compact }
       end