🐛 Fix: Handle empty chart directory correctly

[jklippel]

Currently the return of helmChartNamePath is not checked on errors. This means that the CSO tries to helm template the container which leads to cryptic error messages from helm.

This commit adds a check on errors on the call to helmChartNamePath and results in more helpful error messages by helm.

What this PR does / why we need it:

Which issue(s) this PR fixes (optional, in fixes #<issue number>(, fixes #<issue_number>, ...) format, will close the issue(s) when PR gets merged):
Fixes #288

Special notes for your reviewer:

Please confirm that if this PR changes any image versions, then that's the sole change this PR makes.

The log message after the patch is more helpful:

{"level":"ERROR","time":"2025-04-14T15:28:57.491Z","file":"controller/controller.go:324","message":"Reconciler error","controller":"clusterstackrelease","controllerGroup":"clusterstack.x-k8s.io","controllerKind":"ClusterStackRelease","ClusterStackRelease":{"name":"docker-example-1-32-v0-sha-uxh53fj","namespace":"default"},"namespace":"default","name":"docker-example-1-32-v0-sha-uxh53fj","reconcileID":"584d729e-a19f-4dbd-9c1d-5a45df7edc21","error":"failed to template and apply: failed to template clusterClass helm chart: failed to template clusterClass helm chart: helm chart matching the name filter docker-example-1-32-cluster-class-v0-sha.uxh53fj not found in /tmp/downloads/cluster-stacks/docker-example-1-32-v0-sha-uxh53fj","stacktrace":"sigs.k8s.io/controller-runtime/pkg/internal/controller.(*Controller).reconcileHandler\n\t/home/jakl/GolandProjects/cluster-stack-operator/vendor/sigs.k8s.io/controller-runtime/pkg/internal/controller/controller.go:324\nsigs.k8s.io/controller-runtime/pkg/internal/controller.(*Controller).processNextWorkItem\n\t/home/jakl/GolandProjects/cluster-stack-operator/vendor/sigs.k8s.io/controller-runtime/pkg/internal/controller/controller.go:261\nsigs.k8s.io/controller-runtime/pkg/internal/controller.(*Controller).Start.func2.2\n\t/home/jakl/GolandProjects/cluster-stack-operator/vendor/sigs.k8s.io/controller-runtime/pkg/internal/controller/controller.go:222"}
{"level":"INFO","time":"2025-04-14T15:30:13.992Z","file":"fake/client.go:58","message":"WARNING: called DownloadReleaseAssets of fake assets client","controller":"clusterstackrelease","controllerGroup":"clusterstack.x-k8s.io","controllerKind":"ClusterStackRelease","ClusterStackRelease":{"name":"docker-ferrol-1-27-v2","namespace":"cluster"},"namespace":"cluster","name":"docker-ferrol-1-27-v2","reconcileID":"24134593-9a09-4a19-b8dd-0b5f92e09ee6"}

TODOs:

• squash commits
• include documentation
• add unit tests

[janiskemper]

Thanks a lot for the PR!

We currently have a function CheckHelmCharts that should take care of this. I believe that we forgot to update it for the case of multi-stage cluster addons. I think the proper way of handling this would be to update that function in a way that it does its job.

Can you maybe look into this?

[chess-knight]

We currently have a function CheckHelmCharts that should take care of this. I believe that we forgot to update it for the case of multi-stage cluster addons. I think the proper way of handling this would be to update that function in a way that it does its job.

@janiskemper if I see it correctly, CheckHelmCharts is used only in clusteraddon controller right now, but this PR handles errors in the case of clusterclass

[janiskemper]

@chess-knight true, my bad. However, my point is still the same. We have this function on purpose to check that everything is correct. Apparently, it doesn't do its job. We should fix that function rather than propagating the error in the other function

[jklippel]

@janiskemper I added a call to helmChartNamePath to the validation method. This will show if something is wrong with the name in the helm chart. (Basically it is the same call that raises the error in this case.)

However I would like to keep the propagation of errors, because it is better to get an error message if it is already available than to drop it on purpose. If there are still some unexpected errors this will definitely help debuging.

[janiskemper]

There is the function CheckHelmCharts that has the exact same purpose that you have in mind. Can you plz check how you can add it to that function? I don't mind if you additionally return it with the other function, that should just not be needed anymore

[jklippel]

ok, moved the validation call to CheckHelmCharts().
Unfortunately that did not solve the issue as the CheckHelmCharts() does not get called prior to the original error.
I added a call to CheckHelmCharts() to the Validate() method. Now things work as expected.
Is that what you had in mind @janiskemper ?

[janiskemper]

alright! Thanks for the info. Then the problem is actually that the function was not called in the clusterstackrelease controller. We have this in the clusteraddon-controller:

	// Check for helm charts in the release assets. If they are not present, then something went wrong.
	if err := releaseAsset.CheckHelmCharts(); err != nil {
		msg := fmt.Sprintf("failed to validate helm charts: %s", err.Error())
		conditions.MarkFalse(
			clusterAddon,
			csov1alpha1.ClusterStackReleaseAssetsReadyCondition,
			csov1alpha1.IssueWithReleaseAssetsReason,
			clusterv1.ConditionSeverityError,
			"%s", msg,
		)
		record.Warn(clusterAddon, "ValidateHelmChartFailed", msg)
		return reconcile.Result{}, nil
	}
	```
	
	I think we should add that to respective place in the clusterstackrelease controller. WDYT?