Fix #2619 - When redis feed is empty, fall back to database (#3721)

* Fix #2619 - When redis feed is empty, fall back to database

* Use redis value to return feed from database only while RegenerationWorker
hasn't finished running

* Fix specs

* Replace usage of reject!

1 files changed, 6 insertions, 1 deletions

diff --git a/app/controllers/concerns/user_tracking_concern.rb b/app/controllers/concerns/user_tracking_concern.rb
index 2a3449617..8a63af95d 100644
--- a/app/controllers/concerns/user_tracking_concern.rb
+++ b/app/controllers/concerns/user_tracking_concern.rb
@@ -17,7 +17,7 @@ module UserTrackingConcern
     current_user.update_tracked_fields!(request)
 
     # Regenerate feed if needed
-    RegenerationWorker.perform_async(current_user.account_id) if user_needs_feed_update?
+    regenerate_feed! if user_needs_feed_update?
   end
 
   def user_needs_sign_in_update?
@@ -27,4 +27,9 @@ module UserTrackingConcern
   def user_needs_feed_update?
     current_user.last_sign_in_at < REGENERATE_FEED_DAYS.days.ago
   end
+
+  def regenerate_feed!
+    Redis.current.setnx("account:#{current_user.account_id}:regeneration", true) == 1 && Redis.current.expire("account:#{current_user.account_id}:regeneration", 3_600 * 24)
+    RegenerationWorker.perform_async(current_user.account_id)
+  end
 end