[kube-prometheus-stack] fix reloader-web's app protocol

[abaguas]

What this PR does / why we need it

To integrate this port with applications such as istio the applicationProtocol should be set explicitly.
One solution to enable this integration is to add an appProtocol attribute to the port as explained in the Kubernetes documentation and implemented in this PR. Another alternative is to prefix the port with http-.

Checklist

• DCO signed
• Chart Version bumped
• Title of the PR starts with chart name (e.g. [prometheus-couchdb-exporter])

[abaguas]

If preferred I can rename the port to http-reloader-web or add the appProtocol to the other http ports.
Just let me know

[GMartinez-Sisti]

Hi @abaguas! Thank you for the contribution 🙏

Looks like the appProtocol feature graduated on K8S 1.20, since we support 1.19 it would be nice to have some validation before adding it. Maybe something like this to append it conditionally:

helm-charts/charts/kube-prometheus-stack/templates/_helpers.tpl

Lines 170 to 179 in 3352ef8

	{{/* Get Ingress API Version */}}
	{{- define "kube-prometheus-stack.ingress.apiVersion" -}}
	{{- if and (.Capabilities.APIVersions.Has "networking.k8s.io/v1") (semverCompare ">= 1.19-0" (include "kube-prometheus-stack.kubeVersion" .)) -}}
	{{- print "networking.k8s.io/v1" -}}
	{{- else if .Capabilities.APIVersions.Has "networking.k8s.io/v1beta1" -}}
	{{- print "networking.k8s.io/v1beta1" -}}
	{{- else -}}
	{{- print "extensions/v1beta1" -}}
	{{- end -}}
	{{- end -}}

WDYT?

[abaguas]

Makes sense, thank you for the tip. I implemented it and tested with

$ helm package . && helm template kube-prometheus-stack kube-prometheus-stack-50.3.2.tgz -n monitoring --set kubeTargetVersionOverride="1.19.0" > manifests.yaml      
$ helm package . && helm template kube-prometheus-stack kube-prometheus-stack-50.3.2.tgz -n monitoring --set kubeTargetVersionOverride="1.20.0" > manifests-after.yaml
$ diff manifests.yaml manifests-after.yaml 
1389a1390
>     appProtocol: http
1584a1586
>     appProtocol: http

[QuentinBisson]

Could you move this at the top?

[QuentinBisson]

Otherwise looks good

[QuentinBisson]

@abaguas Can you sign your commits?

[abaguas]

@abaguas Can you sign your commits?

@QuentinBisson done, looks green now.
Sorry for the force-push mess. This week I only have my work computer with me, on which I use a different login so I struggled a bit to amend past commits in the UI and GithubDesktop.
Anyway, it looks good now. Thank you for the review!