Introduce service for merge request pipeline creationcreate-merge-request-create-pipeline-service

We don't have a way to create MR pipeline today, this is one
of the headaches for users.
This change is a preliminary work for the capability.

2 files changed, 38 insertions, 25 deletions

diff --git a/app/services/merge_requests/base_service.rb b/app/services/merge_requests/base_service.rb
index bb9062e9b40..2cfed62ce49 100644
--- a/app/services/merge_requests/base_service.rb
+++ b/app/services/merge_requests/base_service.rb
@@ -60,31 +60,7 @@ module MergeRequests
     end
 
     def create_pipeline_for(merge_request, user)
-      return unless can_create_pipeline_for?(merge_request)
-
-      create_detached_merge_request_pipeline(merge_request, user)
-    end
-
-    def create_detached_merge_request_pipeline(merge_request, user)
-      if can_use_merge_request_ref?(merge_request)
-        Ci::CreatePipelineService.new(merge_request.source_project, user,
-                                      ref: merge_request.ref_path)
-          .execute(:merge_request_event, merge_request: merge_request)
-      else
-        Ci::CreatePipelineService.new(merge_request.source_project, user,
-                                      ref: merge_request.source_branch)
-          .execute(:merge_request_event, merge_request: merge_request)
-      end
-    end
-
-    def can_create_pipeline_for?(merge_request)
-      ##
-      # UpdateMergeRequestsWorker could be retried by an exception.
-      # pipelines for merge request should not be recreated in such case.
-      return false if merge_request.find_actual_head_pipeline&.triggered_by_merge_request?
-      return false if merge_request.has_no_commits?
-
-      true
+      MergeRequests::CreatePipelineService.new(project, user).execute(merge_request)
     end
 
     def can_use_merge_request_ref?(merge_request)
diff --git a/app/services/merge_requests/create_pipeline_service.rb b/app/services/merge_requests/create_pipeline_service.rb
new file mode 100644
index 00000000000..03246cc1920
--- /dev/null
+++ b/app/services/merge_requests/create_pipeline_service.rb
@@ -0,0 +1,37 @@
+# frozen_string_literal: true
+
+module MergeRequests
+  class CreatePipelineService < MergeRequests::BaseService
+    def execute(merge_request)
+      return unless can_create_pipeline_for?(merge_request)
+
+      create_detached_merge_request_pipeline(merge_request)
+    end
+
+    def create_detached_merge_request_pipeline(merge_request)
+      if can_use_merge_request_ref?(merge_request)
+        Ci::CreatePipelineService.new(merge_request.source_project, current_user,
+                                      ref: merge_request.ref_path)
+          .execute(:merge_request_event, merge_request: merge_request)
+      else
+        Ci::CreatePipelineService.new(merge_request.source_project, current_user,
+                                      ref: merge_request.source_branch)
+          .execute(:merge_request_event, merge_request: merge_request)
+      end
+    end
+
+    def can_create_pipeline_for?(merge_request)
+      ##
+      # UpdateMergeRequestsWorker could be retried by an exception.
+      # pipelines for merge request should not be recreated in such case.
+      return false if !allow_duplicate && merge_request.find_actual_head_pipeline&.triggered_by_merge_request?
+      return false if merge_request.has_no_commits?
+
+      true
+    end
+
+    def allow_duplicate
+      params[:allow_duplicate]
+    end
+  end
+end