Public API support for pipelines for merge requestscreate-pipelines-for-merge-request-service

Currently, we don't support pipeline creation for
Pipelines for Merge Requests. We add the support with
a dedicated pipeline creation service.

4 files changed, 31 insertions, 16 deletions

diff --git a/app/services/merge_requests/base_service.rb b/app/services/merge_requests/base_service.rb
index a9dd26c02ad..b6054180070 100644
--- a/app/services/merge_requests/base_service.rb
+++ b/app/services/merge_requests/base_service.rb
@@ -78,10 +78,6 @@ module MergeRequests
     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.merge_request_pipeline_exists?
       return false if merge_request.has_no_commits?
 
       true
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..ed12169ee8c
--- /dev/null
+++ b/app/services/merge_requests/create_pipeline_service.rb
@@ -0,0 +1,11 @@
+# frozen_string_literal: true
+
+module MergeRequests
+  class CreatePipelineService < MergeRequests::BaseService
+    def execute(merge_request)
+      create_pipeline_for(merge_request).tap do |pipeline|
+        merge_request.update_head_pipeline if pipeline&.persisted?
+      end
+    end
+  end
+end
diff --git a/lib/api/merge_requests.rb b/lib/api/merge_requests.rb
index ce85772e4ed..d842f9f9412 100644
--- a/lib/api/merge_requests.rb
+++ b/lib/api/merge_requests.rb
@@ -317,6 +317,26 @@ module API
         present paginate(pipelines), with: Entities::PipelineBasic
       end
 
+      desc 'Create a pipeline for merge request' do
+        success Entities::Pipeline
+      end
+      post ':id/merge_requests/:merge_request_iid/pipeline' do
+        authorize! :create_pipeline, user_project
+
+        mr = find_merge_request_with_access(params[:merge_request_iid])
+
+        pipeline = MergeRequest::CreatePipelineService
+          .new(user_project, current_user).execute(mr)
+
+        not_allowed! unless pipeline
+
+        if pipeline.persisted?
+          present pipeline, with: Entities::Pipeline
+        else
+          render_validation_error!(pipeline)
+        end
+      end
+
       desc 'Update a merge request' do
         success Entities::MergeRequest
       end
diff --git a/spec/services/merge_requests/refresh_service_spec.rb b/spec/services/merge_requests/refresh_service_spec.rb
index d20b2d81763..13cedf781bf 100644
--- a/spec/services/merge_requests/refresh_service_spec.rb
+++ b/spec/services/merge_requests/refresh_service_spec.rb
@@ -240,18 +240,6 @@ describe MergeRequests::RefreshService do
             expect(@merge_request.all_pipelines.second).to be_push
           end
         end
-
-        context "when MergeRequestUpdateWorker is retried by an exception" do
-          it 'does not re-create a duplicate detached merge request pipeline' do
-            expect do
-              service.new(@project, @user).execute(@oldrev, @newrev, 'refs/heads/master')
-            end.to change { @merge_request.merge_request_pipelines.count }.by(1)
-
-            expect do
-              service.new(@project, @user).execute(@oldrev, @newrev, 'refs/heads/master')
-            end.not_to change { @merge_request.merge_request_pipelines.count }
-          end
-        end
       end
 
       context "when .gitlab-ci.yml does not have merge_requests keywords" do