beaker server: backend state is changed but front end UI doesn't get a push update?

[Jonathan Toppins]

Anyone else think it is odd that the backend server state for a machine
entry can change, example schedule setting, and the front end UI doesn't
either get a push update or a 409 conflict error?

Is there a bug filed for this?

-Jon

[Dan Callaghan]

Excerpts from Jonathan Toppins's message of 2017-06-22 15:23 -04:00:
> Anyone else think it is odd that the backend server state for a machine
> entry can change, example schedule setting, and the front end UI doesn't
> either get a push update or a 409 conflict error?
>
> Is there a bug filed for this?

Beaker doesn't have any support for push updates. They are (deceptively) 
hard to implement -- you need some pub-sub message queue on the server 
side to handle notifying waiting clients when a change is made, and you 
probably need to port the whole application to an event-driven async 
style so that it can handle the many thousands of concurrent idling 
WebSockets connections without dedicating a thread to each one.

The job page and recipe page fake it by polling the server for updates 
every 30 seconds, but that's not implemented on any other pages besides 
those ones.

There is also no support for row versioning which could detect 
concurrent modifications and give back a 409 (like Bugzilla's "mid-air 
collision" error message).