[helm] add if for ingressClassName

[jmnote]

• fixes [helm] cannot use default ingressClass #8593

using default ingressClass by default.

AS-IS

$ helm template . --set app.ingress.ingressClassName=hello | grep ingressClassName:
  ingressClassName: hello
$ helm template . --set app.ingress.ingressClassName="" | grep ingressClassName:
  ingressClassName: 
$ helm template . | grep ingressClassName:
  ingressClassName: internal-nginx
$

TO-BE

$ helm template . --set app.ingress.ingressClassName=hello | grep ingressClassName:
  ingressClassName: hello
$ helm template . --set app.ingress.ingressClassName="" | grep ingressClassName:
$ helm template . | grep ingressClassName:
$

If ingressClassName is not specified, the ingressClassName block is omitted. This allows us to use the cluster's default IngressClass.

similar case(helm chart):
https://github.com/prometheus-community/helm-charts/blob/alertmanager-1.7.0/charts/alertmanager/templates/ingress.yaml#L16-L18

k8s docs:
https://kubernetes.io/docs/concepts/services-networking/ingress/#default-ingress-class

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[maciaszczykm]

If ingressClassName is ommited, , a default Ingress class should be defined.

[maciaszczykm]

https://kubernetes.io/docs/concepts/services-networking/ingress/#default-ingress-class

[jmnote]

I confirmed that it can be applied normally even if the value of ingressClassName: is omitted in the YAML file as follows.

apiVersion: networking.k8s.io/v1
kind: Ingress
metadata:
  name: example
spec:
  ingressClassName: #### Only key, no value
  rules:
    - host: example.com
      http:
        paths:
          - pathType: ImplementationSpecific
            backend:
              service:
                name: release-name-kubernetes-dashboard-web
                port:
                  name: web

However, there don't seem to be many cases of empty value in the Kubernetes manifest or Helm Chart value yaml.

[k8s-ci-robot]

PR needs rebase.

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[floreks]

It will be covered by #8735 in here.

/close

[k8s-ci-robot]

@floreks: Closed this PR.

In response to this:

It will be covered by #8735 in here.

/close

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