Move rebase to async worker

Signed-off-by: Dmitriy Zaporozhets <dmitriy.zaporozhets@gmail.com>

app/controllers/projects/merge_requests_controller.rb

@@ -235,8 +235,9 @@ class Projects::MergeRequestsController < Projects::ApplicationController
     return access_denied! unless @merge_request.can_be_merged_by?(current_user)
     return render_404 unless @merge_request.approved?
 
-    MergeRequests::RebaseService.new(merge_request.target_project, current_user).
-      execute(merge_request)
+    RebaseWorker.perform_async(@merge_request.id, current_user.id)
+
+    redirect_to merge_request_path(@merge_request), notice: 'Rebase started. It will take some time'
   end
 
   protected

app/services/merge_requests/rebase_service.rb

@@ -25,14 +25,30 @@ module MergeRequests
 
       # Clone
       output, status = popen(%W(git clone -b #{merge_request.source_branch} -- #{source_project.repository.path_to_repo} #{tree_path}))
-      raise 'Failed to clone repo' unless status.zero?
+
+      unless status.zero?
+        log('Failed to clone repository for rebase:')
+        log(output)
+        return false
+      end
 
       # Rebase
       output, status = popen(%W(git pull --rebase #{target_project.repository.path_to_repo} #{merge_request.target_branch}), tree_path)
-      raise 'Failed to rebase' unless status.zero?
 
+      unless status.zero?
+        log('Failed to rebase branch:')
+        log(output)
+        return false
+      end
+
+      # Push
       output, status = popen(%W(git push -f origin #{merge_request.source_branch}), tree_path)
-      raise 'Failed to push' unless status.zero?
+
+      unless status.zero?
+        log('Failed to push rebased branch:')
+        log(output)
+        return false
+      end
 
       true
     ensure
@@ -50,5 +66,9 @@ module MergeRequests
     def tree_path
       @tree_path ||= Rails.root.join('tmp', 'rebase', source_project.id.to_s, SecureRandom.hex).to_s
     end
+
+    def log(message)
+      Gitlab::GitLogger.error(message)
+    end
   end
 end

app/workers/rebase_worker.rb

+class RebaseWorker
+  include Sidekiq::Worker
+
+  sidekiq_options queue: :default
+
+  def perform(merge_request_id, current_user_id)
+    current_user = User.find(current_user_id)
+    merge_request = MergeRequest.find(merge_request_id)
+
+    MergeRequests::RebaseService.new(merge_request.target_project, current_user).
+      execute(merge_request)
+  end
+end