Cronjob example - add fianlizer

[matrus2]

What do you want to happen?

I wonder why in the cronjob example there is a condition to check if cronjob contains finalizer and if so add it. See:

		if !controllerutil.ContainsFinalizer(cronJob, myFinalizerName) {
			controllerutil.AddFinalizer(cronJob, myFinalizerName)

kubebuilder/docs/book/src/cronjob-tutorial/testdata/finalizer_example.go

Line 69 in 93a0823

if !controllerutil.ContainsFinalizer(cronJob, myFinalizerName) {

However ContainsFinalizer seems to be overkill as AddFinalizer function do the same check inside and it will not add the finalizer once it is already there:

func AddFinalizer(o client.Object, finalizer string) (finalizersUpdated bool) {
	f := o.GetFinalizers()
	for _, e := range f {
		if e == finalizer {
			return false
		}
	}
	o.SetFinalizers(append(f, finalizer))
	return true
}

I would like to remove ContainsFinalizer as it is not needed and update documentation. Before doing so please comment if my reasoning is fine.

Extra Labels

No response

[matrus2]

/assign

[mateusoliveira43]

would suggest a further refactor

AddFinalizer returns a bool telling if the object was updated or not. We could use it to call Update or not

Example idea

                updated := controllerutil.AddFinalizer(cronJob, myFinalizerName)
		if updated {
			if err := r.Update(ctx, cronJob); err != nil {
				return ctrl.Result{}, err
			}
		}

[camilamacedo86]

The CronJob examples should follow the same design approach as the Deploy Image plugin. That means they should be scaffolded in a similar way, with modifications to implement CronJob-specific logic instead of managing an image.

For reference, see this example:
🔗 BusyBox Controller Example

We have issues tracking this effort.

Could you also review the Deploy Image implementation? If you think any improvements should be made there, we should apply them consistently.

Feel free to raise PRs with your suggestions—we can iterate from there! 🚀 If you spot any areas that could be improved, go for it!

Thank you for all your contributions! 🥇