Browser tab with opened WorkspaceLoader hangs when Che Server is unreachable

[sleshchenko]

Description

Browser tab with opened WorkspaceLoader hangs when Che Server is unreachable.

To reproduce it do the following actions:

1. Start a workspace.
2. Scale Che Deployment down to 0 replicas while workspace is starting.
3. Check Browser Tab: requests number grows very fast because of tries to establish WebSocket connection.
   
   Usually after some time tab is crashed or hanged completely.
   

As a possible solution workspace loader should retry to establish WebSocket connection with some period like 1 second(Dashboard does something like that).

OS and version:

Diagnostics:

[garagatyi]

I also suffered from that a lot!

[monaka]

Same here. And I'm trying to fix for a couple of weeks. There have some unhandled promises and unsuitable recovery code. I think it should be almost re-written.

[skabashnyuk]

Related or duplicate #12099. Talked yesterday about this issue with @ashumilova I think we need to review the way how token that uses for websocket connection can be validated on client-side. I think the cause of the current issue and #12099 are related to the expired keycloak session and invalid JWT token.

[sleshchenko]

Related or duplicate #12099.

@skabashnyuk I think they are definitely not duplicated. Because in the case which is described by Mykola - token is expired and in the case I reported - I manually stopped Che Server (it may be crashed or updating), so used token doesn't matter, Che Server endpoints are not available.

[sleshchenko]

Looks like it is still actual even after merging #12421 =(

[garagatyi]

Still actual. Here is screenshot with the trace of component that fires requests

And after just a couple of minutes it makes my PC hang, not only browser tab. I couldn't actually close the tab because it was that overloaded that browser no longer responded at all.
Just a couple of minutes that there are HUNDREDS of THOUSANDS of requests fired (see bottom left corner for the counter)

[garagatyi]

This is really nasty bug that can cause huge confusion for a Che user. @ashumilova since @evidolob is out of reach at the moment, could you check if your team could fix this bug? It is long-running bug that caused a lot of troubles for Che maintainers, so fixing it could improve overall performance of the contributors. Thanks!

[ashumilova]

Added to High Priority Fixes for the next sprint plan.

[garagatyi]

Thanks! I think that @sleshchenko will be way happier when fix lends