[kong] Admission controller - Bring your own certificates (#381)

[ludovic-pourrat]

Add the support of providing your own certificate to the admission controller.

What this PR does / why we need it:

Which issue this PR fixes

• fixes Admission controller - Bring your own certificates #381

Special notes for your reviewer:

Checklist

[Place an '[x]' (no spaces) in all applicable fields. Please remove unrelated fields.]

• PR is based off the current tip of the next branch and targets next, not main
• New or modified sections of values.yaml are documented in the README.md
• Title of the PR and commit headers start with chart name (e.g. [kong])

[shaneutt]

Thanks for this contribution! 🙇

@rainest given your expertise I would like if you could review this as well, but to me this seems functional however I'm wondering if we want to name the values differently?

[rainest]

Overriding the default generated variable values in the template works around the issues I'd laid out in #252 (comment) (it's always at the default location, so the controller doesn't need to worry about pulling them out of a ConfigMap and loading them into the environment instead), so 🥳

Please change admissionWebhook.certificate.ca.bundle to admissionWebhook.certificate.caBundle. That shouldn't be a nested object unless we need to include other CA bundle parameters, and I don't think we ever will.

Along with that, I believe you need something like this:

  clientConfig:
    {{- if not .Values.ingressController.admissionWebhook.certificate.provided }}
    caBundle: {{ b64enc $caCert }}
    {{- else }}
    {{- if .Values.ingressController.admissionWebhook.certificate.caBundle }}
    caBundle: {{ b64enc .Values.ingressController.admissionWebhook.certificate.caBundle }}
    {{- end }}
    {{- end }}

Otherwise, it will always try to set a caBundle field (even if the value is nil) when you set a provided certificate, which you don't want if you issued your certificate from the cluster CA. Do you agree?

[ludovic-pourrat]

@rainest, yes I agree to your feedback, I will change accordingly. Thanks !