incorrect healthCheck API version causes panic

[gwvandesteeg]

Description of issue
If you have an incorrect API version specified in a healthCheck it can cause the controller to panic instead of generating an error message. The default validation process doesn't catch this either.

Expected behaviour
Error message generated logging the details of the issue.

Current behaviour

The healthCheck was defined on a Job type, but had the wrong apiVersion specified, this can be any simple Job you've got specified.

Details
Diff from the patch to the kustomization

   timeout: 5m
   healthChecks:
     # make sure the neo4j bootstrap is ready
-    - apiVersion: v1
+    - apiVersion: batch/v1
       kind: Job
       name: neo4j-bootstrap
       namespace: default

Full working kustomization

---
apiVersion: kustomize.toolkit.fluxcd.io/v1beta1
kind: Kustomization
metadata:
  name: backends-configs
  namespace: flux-system
spec:
  interval: 10m0s
  dependsOn:
    - name: backends
  sourceRef:
    kind: GitRepository
    name: flux-system
  path: ./backends-configs/staging
  prune: true
  validation: client
  timeout: 5m
  healthChecks:
    # make sure the neo4j bootstrap is ready
    - apiVersion: batch/v1
      kind: Job
      name: neo4j-bootstrap-databases
      namespace: default

The panic output

panic: runtime error: invalid memory address or nil pointer dereference
[signal SIGSEGV: segmentation violation code=0x1 addr=0x48 pc=0x1bca585]

goroutine 358 [running]:
github.com/fluxcd/kustomize-controller/controllers.(*KustomizeHealthCheck).Assess(0xc000b29b78, 0x3b9aca00, 0x0, 0x0)
        /workspace/controllers/kustomization_healthcheck.go:97 +0x4a5
github.com/fluxcd/kustomize-controller/controllers.(*KustomizationReconciler).checkHealth(0xc000446140, 0x2389948, 0xc001344d50, 0xc0004a88e0, 0x1c1c919, 0xd, 0xc000be7320, 0x23, 0xc000c58630, 0x10, ...)
        /workspace/controllers/kustomization_controller.go:744 +0xfd
github.com/fluxcd/kustomize-controller/controllers.(*KustomizationReconciler).reconcile(0xc000446140, 0x2389948, 0xc001344d50, 0x1c1c919, 0xd, 0xc000be7320, 0x23, 0xc000c58630, 0x10, 0x0, ...)
        /workspace/controllers/kustomization_controller.go:385 +0xf7b
github.com/fluxcd/kustomize-controller/controllers.(*KustomizationReconciler).Reconcile(0xc000446140, 0x2389948, 0xc001344d50, 0xc0002fa6a0, 0xb, 0xc0002fa680, 0x10, 0xc001344d00, 0x0, 0x0, ...)
        /workspace/controllers/kustomization_controller.go:233 +0xe58
sigs.k8s.io/controller-runtime/pkg/internal/controller.(*Controller).reconcileHandler(0xc00021e3c0, 0x23898a0, 0xc000376000, 0x1e1e180, 0xc0005521a0)
        /go/pkg/mod/sigs.k8s.io/[email protected]/pkg/internal/controller/controller.go:298 +0x30d
sigs.k8s.io/controller-runtime/pkg/internal/controller.(*Controller).processNextWorkItem(0xc00021e3c0, 0x23898a0, 0xc000376000, 0x0)
        /go/pkg/mod/sigs.k8s.io/[email protected]/pkg/internal/controller/controller.go:253 +0x205
sigs.k8s.io/controller-runtime/pkg/internal/controller.(*Controller).Start.func2.2(0xc000058bd0, 0xc00021e3c0, 0x23898a0, 0xc000376000)
        /go/pkg/mod/sigs.k8s.io/[email protected]/pkg/internal/controller/controller.go:214 +0x6b
created by sigs.k8s.io/controller-runtime/pkg/internal/controller.(*Controller).Start.func2
        /go/pkg/mod/sigs.k8s.io/[email protected]/pkg/internal/controller/controller.go:210 +0x425

version information:

$ flux check
► checking prerequisites
✔ kubectl 1.21.0 >=1.18.0-0
✔ Kubernetes 1.20.7-eks-d88609 >=1.16.0-0
► checking controllers
✔ helm-controller: deployment ready
► ghcr.io/fluxcd/helm-controller:v0.11.2
✔ kustomize-controller: deployment ready
► ghcr.io/fluxcd/kustomize-controller:v0.14.1
✔ notification-controller: deployment ready
► ghcr.io/fluxcd/notification-controller:v0.16.0
✔ source-controller: deployment ready
► ghcr.io/fluxcd/source-controller:v0.15.4
✔ all checks passed

List showing details of the # of restarts on the controller.

$ kubectl get pods -n flux-system
NAME                                       READY   STATUS    RESTARTS   AGE
helm-controller-dc6ffd55b-p5v58            1/1     Running   0          5d19h
kustomize-controller-6c8cfccb59-8qhrn      1/1     Running   798        5d19h
notification-controller-8494bfd747-f9llm   1/1     Running   0          5d19h
source-controller-7445c6755-sz7bf          1/1     Running   0          5d19h

[makkes]

I was able to reproduce it. Thanks @gwvandesteeg for raising this. I will address it asap.