NATS-Cr in in deletion state results in eventing-cr in error state

[k15r]

Description

Enable nats module
Enable eventing module set backend to NATS

delete nats module

expected result

1. nats module stays in warning as eventing still uses nats
2. eventing module is still ready as all required resources (working nats cluster) still exist. We could debate that it changes to warning state as nats will we removed eventually

actual result

1. nats changes to warning
2. eventing changes to error

NATS-CR:

apiVersion: operator.kyma-project.io/v1alpha1
kind: NATS
metadata:
  creationTimestamp: '2023-11-14T09:04:14Z'
  deletionGracePeriodSeconds: 0
  deletionTimestamp: '2023-11-23T10:44:53Z'
  finalizers:
    - nats.operator.kyma-project.io/finalizer
  generation: 4
  name: eventing-nats
  namespace: kyma-system
  resourceVersion: '11810215'
  uid: 2df4b98a-bd34-4068-a33a-14f5f723d5f2
[...]
status:
  conditions:
    - lastTransitionTime: '2023-11-23T10:44:53Z'
      message: Cannot delete NATS cluster as stream consumer exists
      reason: DeletionError
      status: 'False'
      type: Deleted
    - lastTransitionTime: '2023-11-16T03:49:48Z'
      message: StatefulSet is ready
      reason: Available
      status: 'True'
      type: StatefulSet
    - lastTransitionTime: '2023-11-16T03:49:48Z'
      message: NATS is deployed
      reason: Deployed
      status: 'True'
      type: Available
  state: Warning

Eventing-CR

status:
  activeBackend: NATS
  conditions:
    - lastTransitionTime: '2023-11-23T10:44:54Z'
      message: NATS server is not available
      reason: NotAvailable
      status: 'False'
      type: NATSAvailable
    - lastTransitionTime: '2023-11-14T09:01:40Z'
      message: Webhook is available
      reason: Ready
      status: 'True'
      type: WebhookReady
    - lastTransitionTime: '2023-11-14T09:05:22Z'
      message: Publisher proxy is deployed
      reason: Deployed
      status: 'True'
      type: PublisherProxyReady
  specHash: 6255885275764877000
  state: Error

[k15r]

The change introduced here does not check if the actual nats resources are still available. Eventing can be ready even if NO Nats resources are available

[k15r]

eventing should base the readiness of the nats backend on the availability of the nats cluster.