20+ seconds faster Che-Theia startup

[azatsarynnyy]

Describe the bug

It takes about 10 sec. after Che-Theia is loaded to the browser and before the project tree is rendered.

Che version

next (development version)

Steps to reproduce

Start a new workspace with the following factory URL:
<che-host>#https://github.com/l0rd/spring-petclinic?devfilePath=.devfilev2.yaml

It takes about 10 sec. before the project tree is rendered. During that time the tree is empty. However, the project sources are already cloned.

Expected behavior

The projects tree should be rendered as soon as Che-Theia page is loaded to the browser.

Runtime

OpenShift

Screenshots

Installation method

OperatorHub

Environment

Linux

Release Notes Text

The previous DevWorkspace based Che-Theia used to take more than 20 seconds to load due to some blocking built-in plugins startup. The built-in plugins are not blocking the main Theia process startup anymore.

[RomanNikitenko]

I detected that we have the delay at sync plugins step. It's actual for the dev workspace mode only.
Looking for a cause of the problem...

[benoitf]

@azatsarynnyy 7.41.0 release will be cut tomorrow. This issue is not yet closed, so please close it if it's done or move it to 7.42

[RomanNikitenko]

I had a quite long vacation, will come back to the issue today/tomorrow...

[RomanNikitenko]

I detected that the system hangs on getDeployedPluginIds step.
It looks like frontend waits for the backend at that step:

I investigated the problem using minikube locally on my machine. As you can see the delay for my machine is about 40 seconds.

Finally, I found that we are waiting for unpacking che-theia plugins at that delay.
The plugins are unpacked in parallel, but it takes about 30 seconds (in my environment) to unpack some of them.

I tried to put already unpacked che-theia plugins to the corresponding image and added an entity (like PluginTheiaFileHandler) which handles them.
You can see the difference for my environment on the videos bellow.

Behaviour for packed che-theia plugins, so main branch without any changes - the plugins are unpacked at starting backend

start_workspace_packed_plugins.mp4

Behaviour for unpacked che-theia plugins, so with my changes - plugins are unpacked at building images step

unpacked_plugins_2.mp4

[azatsarynnyy]

@l0rd actually, it's > 20 sec. faster for hosted Che instance
and > 30 sec. for the local minikube installation

just FYI 🙂

[l0rd]

@azatsarynnyy thanks. I have updated the title and the release notes.

[devstudio-release]

sync'd to Red Hat JIRA https://issues.redhat.com/browse/CRW-2712