ActionCable server response times on Heroku

Question

I've implemented a real-time chat system using ActionCable. It works, but I keep getting exception notices from Rollbar for the /cable endpoint in production (Heroku).

2017-07-18T15:36:54.738588+00:00 heroku[router]: at=info method=GET path="/cable?user_id=63191&client=Gc-CvUfsgAW70KMpIBX25A&access_token=MoBTM2jF9wTwqblMsXQcVA" host=my-api.herokuapp.com request_id=b6cc263c-19e4-4207-8ce4-65ed6a130133 fwd="61.55.27.1" dyno=web.1 connect=0ms service=1727122ms status=101 bytes=22232 protocol=https

Notice that it took 1727122ms. If the websocket is active, that's not surprising, but it seems to be staying open even after the client has stopped doing anything. Do I have something in ActionCable configured incorrectly, or is this expected? Should I just suppress the error notification in Rollbar?

Answer 1

My guess is that you just need to configure Rollbar to exclude paths matching "/cable?" for the slow request filter. Ask their support team, they've undoubtedly experienced this before.