POC: Add support for Release Namespace creation

[ichekrygin]

Overview

Currently, in Helm3 there is no way to create Release Namespace during helm chart installation.

Change

Implement functionality to support Release Namespace creation during helm chart install.
While this PR is marked as Proof of Concept (POC) - it attempts at a fully functional solution.
The initial purpose of this PR is to illustrate and support Proposal #6794

Tracking

This issue and the proposed solution is captured in #6794

Additional Context

This issue was discussed previously in and/or partially related to #3305, #5628, #5753

[cannibal-kush]

Popular request. This also happens to pertain to Microsoft's fabrikate project, which necessitates a feature they call injectNamespace.

[bacongobbler]

This could be accomplished using the new lookup function once we merge #7474. #7473 (comment) demonstrates an example that accomplishes the same thing this PR is asking for: if the namespace does not exist, create it.

Because of that, I'm in favour of closing this, as the use case provided in #6794 can be accomplished using that pattern without introducing any further code.

[ichekrygin]

I briefly scanned #7473 and not fully (yet) understand how does lookup help with Release.Namespace creation. Is it possible to TL;DR; it possibly answering 2 questions:

• will the lookup help/allow implicit creation of nonexistent release namespace
• will the lookup help/allow explicit creation of nonexistent release namespace (declaring of namespace in the chart template)

Thank you.

[bacongobbler]

yes and yes. Please have a look at the comment I linked above.

[bacongobbler]

Please try it out and let us know if you have further questions.

[mattfarina]

@bacongobbler A few things occurred to me...

1. The method described in a failed lookup removes all rendered output #7473 (comment) is different in that the chart creator needs to add that rather than it being the ability of the chart installer to do. It moves the role the feature is leveraged by. Wouldn't this be better off as an application operator feature rather than an application distribution feature?
2. This new setup is generally undocumented. Before this can be closed it should be documented on helm.sh.

If someone is installing someone else's chart they will need to fork it to add the namespace adding. Especially if the chart was designed for Helm v2. I would be interested in landing this to make it easier on app operators / consumers. Thoughts?

[ichekrygin]

Reposting here (since I can't seem to keep up w/ closing): #7473 (comment)

[ichekrygin]

Also see this: #6794 (comment)

[mattfarina]

@ichekrygin Could your rebase your commits. There is now a conflict because of changes to the go.mod and go.sum files.

[ichekrygin]

@mattfarina - rebased, PTAL.

[bacongobbler]

Closing in favour of #7648, which was merged this morning.