Extract pipeline persistence to a separate chain class

app/services/ci/create_pipeline_service.rb

@@ -3,9 +3,10 @@ module Ci
     attr_reader :pipeline
 
     SEQUENCE = [Gitlab::Ci::Pipeline::Chain::Validate,
-                Gitlab::Ci::Pipeline::Chain::Skip].freeze
+                Gitlab::Ci::Pipeline::Chain::Skip,
+                Gitlab::Ci::Pipeline::Chain::Create].freeze
 
-    def execute(source, ignore_skip_ci: false, save_on_errors: true, trigger_request: nil, schedule: nil)
+    def execute(source, ignore_skip_ci: false, save_on_errors: true, trigger_request: nil, schedule: nil, &block)
       @pipeline = Ci::Pipeline.new(
         source: source,
         project: project,
@@ -19,43 +20,31 @@ module Ci
         protected: project.protected_for?(ref)
       )
 
+      @pipeline.tap do |pipeline|
         command = OpenStruct.new(ignore_skip_ci: ignore_skip_ci,
                                  save_incompleted: save_on_errors,
                                  trigger_request: trigger_request,
                                  schedule: schedule,
+                                 seeds_block: block,
                                  project: project,
                                  current_user: current_user)
 
         sequence = SEQUENCE.map { |chain| chain.new(pipeline, command) }
 
-      done = sequence.any? do |chain|
+        sequence_complete = sequence.none? do |chain|
           chain.perform!
           chain.break?
         end
 
         update_merge_requests_head_pipeline if pipeline.persisted?
 
-      return pipeline if done
-
-      begin
-        Ci::Pipeline.transaction do
-          pipeline.save!
-
-          yield(pipeline) if block_given?
-
-          Ci::CreatePipelineStagesService
-            .new(project, current_user)
-            .execute(pipeline)
-        end
-      rescue ActiveRecord::RecordInvalid => e
-        return error("Failed to persist the pipeline: #{e}")
-      end
-
-      update_merge_requests_head_pipeline if pipeline.persisted?
+        if sequence_complete
           cancel_pending_pipelines if project.auto_cancel_pending_pipelines?
           pipeline_created_counter.increment(source: source)
 
-      pipeline.tap(&:process!)
+          pipeline.process!
+        end
+      end
     end
 
     private

lib/gitlab/ci/pipeline/chain/create.rb

+module Gitlab
+  module Ci
+    module Pipeline
+      module Chain
+        class Create < Chain::Base
+          def perform!
+            ::Ci::Pipeline.transaction do
+              pipeline.save!
+
+              if @command.seeds_block
+                @command.seeds_block.call(pipeline)
+              end
+
+              ::Ci::CreatePipelineStagesService
+                .new(project, current_user)
+                .execute(pipeline)
+            end
+          rescue ActiveRecord::RecordInvalid => e
+            pipeline.erros.add(:base, "Failed to persist the pipeline: #{e}")
+          end
+
+          def break?
+            !pipeline.persisted?
+          end
+        end
+      end
+    end
+  end
+end