Add ActiveSupport::Notifications hook to Broadcaster#broadcast

This addition of this notification hook will give users better visibility
into the messages being sent over the PubSub adapter.

1 files changed, 6 insertions, 2 deletions

diff --git a/actioncable/lib/action_cable/server/broadcasting.rb b/actioncable/lib/action_cable/server/broadcasting.rb
index 8f93564113..1fc58baa3e 100644
--- a/actioncable/lib/action_cable/server/broadcasting.rb
+++ b/actioncable/lib/action_cable/server/broadcasting.rb
@@ -39,8 +39,12 @@ module ActionCable
 
           def broadcast(message)
             server.logger.info "[ActionCable] Broadcasting to #{broadcasting}: #{message.inspect}"
-            encoded = coder ? coder.encode(message) : message
-            server.pubsub.broadcast broadcasting, encoded
+
+            payload = { broadcasting: broadcasting, message: message, coder: coder }
+            ActiveSupport::Notifications.instrument("broadcast.action_cable", payload) do
+              encoded = coder ? coder.encode(message) : message
+              server.pubsub.broadcast broadcasting, encoded
+            end
           end
         end
     end