I have a nodejs application which uses the phoenix javascript package to connect to a phoenix application. It works fine as long as I do not restart the phoenix application. Once I restart it, I have to manually restart the node app as well.

I tried various setups, but it seems to be an issue with docker. Whenever I start the app locally (iex -S mix phx.server, mix phx.server, mix release && _…, prod and dev) it works as expected. After shutting down my phoenix app, node tries to reconnect. But as soon as I start the release in my docker container, node does not try to reconnect any more.

I also created a minimal web app which does show the same symptoms. Just to make sure, that it is not related to the node js websocket libraries.

UPDATE: I created a new socket + channel for testing purposes and it seems to be working there. So there has to be something wrong with my socket or channel implementation.

UPDATE: By carefully removing code, it boiled down to an issue with Phoenix.Tracker.
When removing the Phoenix.Tracker.track(…) code it works without any issues.

Has anyone an idea what might cause this behaviour. I guess I made a mistake but I have no idea which