Operator should error out when credentialsSecret is missing

[sbernauer]

Affected version

0.0.0-dev

Current and expected behavior

When spec.clusterConfig.credentialsSecret points to a non-existent Secret the operator should error out, currently it just does not apply a Job manifests, no error is shown.
At least the following code is affected:

airflow-operator/rust/operator-binary/src/airflow_db_controller.rs

Line 158 in e767be7

if secret.is_some() {

Possible solution

No response

Additional context

---
apiVersion: airflow.stackable.tech/v1alpha1
kind: AirflowCluster
metadata:
  name: airflow2
spec:
  image:
    productVersion: 2.6.1
    stackableVersion: 0.0.0-dev
  clusterConfig:
    executor: CeleryExecutor
    loadExamples: false
    exposeConfig: false
    credentialsSecret: simple-airflow-credentials # <<< Does not exist
    dagsGitSync:
      - repo: https://github.com/stackabletech/XXX
        branch: "main"
        gitFolder: "airflow_dags"
        depth: 10
        wait: 20
        gitSyncConf:
          --rev: HEAD
  webservers:
    roleGroups:
      default:
        replicas: 1
  workers:
    roleGroups:
      default:
        replicas: 2
  schedulers:
    roleGroups:
      default:
        replicas: 1

Environment

No response

Would you like to work on fixing this bug?

None

[Maleware]

#293 fixed by