fix: adds WebSocket ping to interactive terminal (#14191)

[erhudy]

This adds a WebSocket ping message on a 5-second interval, sent from the server to the client. This ensures that the interactive terminal will remain open and won't be closed by load balancers that are reaping idle connections.

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[codecov]

Codecov Report

Patch coverage has no change and project coverage change: +0.01 🎉

Comparison is base (ec2fff5) 49.61% compared to head (a218ef5) 49.62%.

Additional details and impacted files

@@            Coverage Diff             @@
##           master   #14192      +/-   ##
==========================================
+ Coverage   49.61%   49.62%   +0.01%     
==========================================
  Files         256      257       +1     
  Lines       43829    43973     +144     
==========================================
+ Hits        21744    21820      +76     
- Misses      19948    20006      +58     
- Partials     2137     2147      +10     

Impacted Files	Coverage Δ
server/application/terminal.go	12.44% <0.00%> (-0.24%)	⬇️
server/application/websocket.go	4.54% <0.00%> (-1.43%)	⬇️

... and 4 files with indirect coverage changes

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[crenshaw-dev]

@erhudy let's get this into 2.8 at least. If it doesn't cause any problems, we can cherry-pick back to previous releases.

[crenshaw-dev]

/cherry-pick release-2.8

[bradenwright-opunai]

What version was this added to, I' on v2.8.0+804d4b8 but we are still running into this issue.

[bradenwright-opunai]

Fwiw, I tried to upgrade to v2.8.3+77556d9 but it still seems to hang, any idea of what version got fixed or if there is a further problem.

[erhudy]

I am running 2.8.2 and the fix is certainly present there, which I just verified by leaving a terminal open for more than 60 seconds.

[bradenwright-opunai]

@erhudy do you have a way for me to confirm that the fix is trying to keep the terminal open or not. So I can determine if this is a new bug. Or if some reason the fix isn't working. B/c it seems like maybe I have an edge case that the fix isn't considering.

I think the issue maybe that the Terminal is locking before if hits 1 min, like for example I tried to click off and come back after 45 secs and the terminal had locked. I can check timeouts or anything else people can think of that may effect this with a Load Balancer in GCP b/c it works fine with port-forrwarding to the ArgoCD Server.

Seems like the timeout for the LB is set to 30 secs so let me try to increase that and test again.

[bradenwright-opunai]

Alright so in GCP the default timeout for a backend service is 30 secs, with the default settings the terminal was hanging. After increasing that timeout > 60 secs (currently set for 3600 secs ie 1 hr) and I've been able to wait 10+ mins and return to a working terminal. Everything is working now as expected.

I would recoomend that the docs https://argo-cd.readthedocs.io/en/stable/operator-manual/web_based_terminal/ be updated to call out the 60 sec check that now exists and that for LB's the timeout needs to be > 60 secs

[erhudy]

That seems unusual. I don't have a Google Cloud environment to test in - I developed this fix against an AWS ALB where the timeout is 60 seconds, and my terminals definitely live longer than that with no activity now. It shouldn't be necessary to set a 1h timeout on your LB. I did check DevTools in Edge/Firefox/Safari to see if they recorded ping/pong activity for WebSocket but did not see anything on any browser I checked.

[bravosierrasierra]

#14271
How to enable this ping feature?