Helm values files for CLI

[scottboring]

Description

Adding optional flag for values file similar to helm values file making CLI easier to use when multiple values need to be overridden. The new flag is --values, the same as helm and functions the same way in that is supports multiple files including files from URLs.

How Has This Been Tested?

Tested multiple scenarios locally

• Install help message
• Install without values param
• Install with 1 values param
• Install with 2 values params
• Install with --set overriding --values params
• Install fails with invalid values file
• Install fails values file not found

[adamjensenbot]

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[cheina97]

Hi @scottboring thanks for your PR, that's something we planned to implement and I'm sure it will be really useful in the future. So thanks for your commitment to our project and your time, we really appreciate it.

Just a few comments:

1. I think it would be more correct to implement the behaviour of the --values flag here. You can override the values file retrieved by helm.
2. Suggestion: get inspiration from here in order to emulate the helm --values flag behaviour
3. I would expect the --values flag does not have priority on the rest of the flags, especially --set (like in helm).
4. Please adds an explanation of the --values flag in the documentation.
5. Please put the PR in draft till it is ready (it includes linting check).

[scottboring]

Hi @cheina97, thank you for the review and comments.

1. I don't follow this, how would this logic be implemented here and why wouldn't it be next to the logic for the --set flag?
2. I can make some changes to use or copy that code
3. The --values flag overrides is ran before the --set flag so this priority is aligns with your expectations. I have also tested this.
4. I'lll update the documentation
5. This has been converted to draft

If you could please provide some more detail around the points 1 & 2, that would be helpful to ensure the changes I make align with your expectations.

[cheina97]

1/3. You are right, it's better to place the --values override where it is right now.
2. I think it's a good idea to copy that code to be sure to behave like expected in Helm.

[scottboring]

Hi @cheina97, I've made the requested updates. Thank you for reviewing my PR and providing feedback. Let me know if there is any other feedback.

Note that I used the Helm cli env settings here which I'm not sure is correct but aligns with how Helm works: https://github.com/liqotech/liqo/pull/1974/files#diff-a849a3ee27a1eaa15291b34f78d4adee1ef1e4e268d48eb3dd1338acb2f2c685R422

[cheina97]

Please, launch make generate to fix the majority of lining errors.

[scottboring]

Hi @cheina97, I believe this PR is ready to be merged.

[cheina97]

Please, can you squash the commits?

[scottboring]

@cheina97 commits have been squashed

[cheina97]

/rebase test=true

[cheina97]

lgtm

[cheina97]

/merge