K8SSAND-1368 ⁃ Refactor webhook logic

[Miles-Garnsey]

What is missing?

We need to look at the webhook logic with a view to refactoring it out of APIs.

Why do we need it?

As part of delivering #235 via #482 I've been struggling to:

1. Share validation logic between reconcilers and webhooks via pkg packages.
2. Access test utilities in pkg/test

This is because most of pkg imports parts of apis, and - because the webhooks are also in apis

• trying to import pkg items back into apis creates a cycle.

Complication

It seems that (somewhat unfortunately) the webhooks must be in APIs due to constraints around the way the types are imported into the scheme.

I'm not 100% sure how to solve this, but this ticket to track research on a solution.

┆Issue is synchronized with this Jira Story by Unito

[jsanda]

Please add your planning poker estimate with ZenHub @burmanm

[jsanda]

Please add your planning poker estimate with ZenHub @Miles-Garnsey

[Miles-Garnsey]

I'd make this a research ticket time boxed at 2 days initially. Back of the envelope from my prelim research suggets:

• 4 days to determine how to treat all types as external types. This is high risk as the documentation is incomplete according to this open issue.
• 4 days to refactor.

Above estimates are rough and subject to change post research step.