Move NotificationService calls to Sidekiq

The NotificationService has to do quite a lot of work to calculate the
recipients for an email. Where possible, we should try to avoid doing this in an
HTTP request, because the mail are sent by Sidekiq anyway, so there's no need to
schedule those emails immediately.

This commit creates a generic Sidekiq worker that uses Global ID to serialise
and deserialise its arguments, then forwards them to the NotificationService.
The NotificationService gains an `#async` method, so you can replace:

    notification_service.new_issue(issue, current_user)

With:

    notification_service.async.new_issue(issue, current_user)

And have everything else work as normal, except that calculating the recipients
will be done by Sidekiq, which will then schedule further Sidekiq jobs to send
each email.

4 files changed, 6 insertions, 6 deletions

diff --git a/app/services/issues/close_service.rb b/app/services/issues/close_service.rb
index fee5bc38f7b..4a99367c575 100644
--- a/app/services/issues/close_service.rb
+++ b/app/services/issues/close_service.rb
@@ -26,7 +26,7 @@ module Issues
         issue.update(closed_by: current_user)
         event_service.close_issue(issue, current_user)
         create_note(issue, commit) if system_note
-        notification_service.close_issue(issue, current_user) if notifications
+        notification_service.async.close_issue(issue, current_user) if notifications
         todo_service.close_issue(issue, current_user)
         execute_hooks(issue, 'close')
         invalidate_cache_counts(issue, users: issue.assignees)
diff --git a/app/services/issues/move_service.rb b/app/services/issues/move_service.rb
index 7140890d201..78e79344c99 100644
--- a/app/services/issues/move_service.rb
+++ b/app/services/issues/move_service.rb
@@ -139,7 +139,7 @@ module Issues
     end
 
     def notify_participants
-      notification_service.issue_moved(@old_issue, @new_issue, @current_user)
+      notification_service.async.issue_moved(@old_issue, @new_issue, @current_user)
     end
   end
 end
diff --git a/app/services/issues/reopen_service.rb b/app/services/issues/reopen_service.rb
index 62b4b4b6a1e..02224f3357a 100644
--- a/app/services/issues/reopen_service.rb
+++ b/app/services/issues/reopen_service.rb
@@ -6,7 +6,7 @@ module Issues
       if issue.reopen
         event_service.reopen_issue(issue, current_user)
         create_note(issue, 'reopened')
-        notification_service.reopen_issue(issue, current_user)
+        notification_service.async.reopen_issue(issue, current_user)
         execute_hooks(issue, 'reopen')
         invalidate_cache_counts(issue, users: issue.assignees)
         issue.update_project_counter_caches
diff --git a/app/services/issues/update_service.rb b/app/services/issues/update_service.rb
index 1374f10c586..1000e1842b6 100644
--- a/app/services/issues/update_service.rb
+++ b/app/services/issues/update_service.rb
@@ -30,7 +30,7 @@ module Issues
 
       if issue.assignees != old_assignees
         create_assignee_note(issue, old_assignees)
-        notification_service.reassigned_issue(issue, current_user, old_assignees)
+        notification_service.async.reassigned_issue(issue, current_user, old_assignees)
         todo_service.reassigned_issue(issue, current_user, old_assignees)
       end
 
@@ -41,13 +41,13 @@ module Issues
       added_labels = issue.labels - old_labels
 
       if added_labels.present?
-        notification_service.relabeled_issue(issue, added_labels, current_user)
+        notification_service.async.relabeled_issue(issue, added_labels, current_user)
       end
 
       added_mentions = issue.mentioned_users - old_mentioned_users
 
       if added_mentions.present?
-        notification_service.new_mentions_in_issue(issue, added_mentions, current_user)
+        notification_service.async.new_mentions_in_issue(issue, added_mentions, current_user)
       end
     end