Refactor previewctl install-context

[vulkoingim]

Description

• Changes the underlying implementation of the previewctl install-context command from bash to go and adds tests
• Changes parts of the get-credentials command, that was introduced recently so it fits better with the new design and adds tests to some of the functions as well
• It doesn't change how preivewctl is used and the context is installed in workspaces yet (follow up pr will deal with that)

Related Issue(s)

Fixes https://github.com/gitpod-io/ops/issues/5763

How to test

gcloud auth login

cd dev/preview/previewctl 

KUBECONFIG=$(pwd)/tmp go run main.go install-context

Release Notes

NONE

Documentation

Werft options:

• /werft with-local-preview
  If enabled this will build install/preview
• /werft with-preview
• /werft with-large-vm
• /werft with-integration-tests=all
  Valid options are all, workspace, webapp, ide

[mads-hartmann]

This is awesome Aleks. I left a few inline comments.

For a big PR like this I would have loved a PR description that provided more context about the change. Here are a few questions I have that would have been nice to have in the PR description.

1. We'll have to bump the version of previewctl in the image (unfortunately). This isn't done in this PR so I'm assuming you'll do it in a follow-up PR.
2. With this change we should be able to delete this
3. Install-contexts isn't used in any of the Werft jobs yet. What's the plan for using it? It would be nice to be able to delete this and switch any invocations of it like this to use install-context. We should also be able to simplify the Werft job by removing the stateful handling of port-forwarding that install-context now takes care of (e.g. removing this and related code)

[vulkoingim]

For a big PR like this I would have loved a PR description that provided more context about the change. Here are a few questions I have that would have been nice to have in the PR description.

Yeah I agree - I just marked it ready for review when I was mostly done with it yesterday and left the description for today. Didn't think that anyone will review it that soon 😄

1. We'll have to bump the version of previewctl in the image (unfortunately). This isn't done in this PR so I'm assuming you'll do it in a follow-up PR.

Yep

2. With this change we should be able to delete this

Also yes

It would be nice to be able to delete this

Will remove this eventually

switch any invocations of it like this

Will change this later as well

We should also be able to simplify the Werft job by removing the stateful handling of port-forwarding that install-context now takes care of (e.g. removing this and related code)

Yeah, we should be able to remove this and the part that copies the context in the job also.

Edit: Issue for ☝️

[mads-hartmann]

🛹 🚀