Create instant feedback when a task is clicked without waiting for the task to actually spawn server-side.

[vparfonov]

Is your enhancement related to a problem? Please describe.

The delay between "the user clicks on the task" and "the output terminal is getting shown". The user doesn't really know if the action (clicking on the task) has been taken into account. When the connectivity is not great, this lead to very inconvenient UX.

Describe the solution you'd like

We should look at how we can first open the terminal output, so it gives a visual feedback to the end-user, display an indicator inside of it (ex: "Task "{task-name}" - Connecting....") and then do the necessary background connection between the task running in the container and the output displayed in the IDE

Describe alternatives you've considered

Additional context

[tolusha]

it sounds like a Theia issue

[vitaliy-guliy]

On che.openshift.io vanilla Theia runs tasks very fast. It looks like eclipse-che-theia extensions and eclipse-che plugins forces to have a 2 seconds delay in running of shell tasks and around 5 seconds for che tasks.

Will create a detailed report on the process of executing of che tasks, measuring the execution time.

[tsmaeder]

Making the UI async might also help with #15541

[vitaliy-guliy]

Timings benchmarks of execution of Che and Theia (shell) tasks on che.openshift.io

1. Theia task
1st execution	getting workspace tasks, resolve task macroses	1.5 seconds
	launching task on the backend	0.2 seconds
	Appeparing the terminal in	1.7 seconds
2nd, 3rd execution	getting workspace tasks, resolve task macroses	1.3 seconds
	launching task on the backend	0.2 seconds
	Appeparing the terminal in	1.5 seconds
2. Che task
1st execution	getting workspace tasks, resolve task macroses	1.5 seconds
	launching task on the backend	2.7 seconds
	Appeparing the terminal in	4.2 seconds
2nd, 3rd execution	getting workspace tasks, resolve task macroses	1.3 seconds
	launching task on the backend	1.9 seconds
	Appeparing the terminal in	3.2 seconds

The reasons of such big delay are:

• handler for Che tasks is located in tasks-plugin
• too many communications between Theia and plugins when executing a command
• Che terminal is opened from the task-plugin using theia.window.createTerminal() method of Plugin API, instead of being opened from Theia task service in task extension
• network and hosted che server load

It was tested with a full set of plugins, with few plugins and without plugins. The conclusion: amount of plugins does not affect on the delay.

[tsmaeder]

@vitaliy-guliy all these measurements seem very long in comparison to running just plain Theia on my laptop. Do you think it's just the lower-powered environment compared to a laptop or some overhead introduced by OpenShift/Kubernetes/Storage?

[vitaliy-guliy]

That local Theia works fast enough could be because your laptop is quite powerful. But I think it's mostly because everything's running locally. In this case, there is no delay that network adds.
And yes, OpenShift/Kubernetes affects on the task running, but we need to investigate how we can test it.

[vitaliy-guliy]

Could potentially be related to eclipse-theia/theia#7496