Modernize Go code with latest style conventions

[fmount]

Applied automated modernization using gopls modernize tool to update:

• Replace interface{} with any type alias (Go 1.18+)
• Update range loops to use idiomatic range syntax
• Replace fmt.Sprintf with fmt.Appendf where appropriate

These changes improve code readability and align with current Go best practices.
Co-Authored-By: Claude [email protected]

[fmount]

seems in line with [1]. @stuggi do you see any potential problem with this?

[1] https://github.com/openshift/api/blob/master/route/v1/types.go#L132

[stuggi]

in this copy we intentionally set everything to optional + omitempty for not showing all in the override spec + e.g. we have to remove required as we want to be able to override only a subset without the need to provide any required parameter, as in the org we copied it from

https://github.com/openstack-k8s-operators/lib-common/pull/646/files#diff-46b504a7b63ab60d45329974187748c60c8979cde8a28b43ce40c350f000094dR102-103

[fmount]

I suspect it removes omitempty because we have // +kubebuilder:validation:optional. @stuggi do we want to keep the original version? (this comment applies to L112 as well).

[stuggi]

afaik, for a struct like APIService, its zero value is an instance where all its fields are empty (e.g., nil pointers, empty strings, 0 for numbers). so I think we want omitempty to not show the defaults of the sub struct?

[fmount]

ack, in general I'll restore omitempty for both APIService and TargetReference, so we do not risk to have any unwanted change to the CRD that might result in unwanted behavior due to a change in the existing CRs.
From what I can see in a lab, all my deployed services have:

tls:
  api:
     internal: {}
     public: {}

which I think means that omitempty at APIService level is not useful because the underlying fields:

// APIService - API tls type which encapsulates for API services
type APIService struct {
	// +kubebuilder:validation:optional
	// +operator-sdk:csv:customresourcedefinitions:type=spec
	// Public GenericService - holds the secret for the public endpoint
	Public GenericService `json:"public"`

	// +kubebuilder:validation:optional
	// +operator-sdk:csv:customresourcedefinitions:type=spec
	// Internal GenericService - holds the secret for the internal endpoint
	Internal GenericService `json:"internal"`
}

have not omitempty, and therefore are always rendered in the resulting CR.

[fmount]

To TargetReference `json:"to" protobuf:"bytes,3,opt,name=to", instead, is different, because omitempty in that case takes effect because the underlying fields have omitempty as well.

[fmount]

Done, I restored the omitempty tags so we don't risk to get any side effect due to this change.

[abays]

/lgtm