ScaledObject with Pulsar scaler makes operator crash if authModes is missing

[kastriotdobratiqi]

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Keda operator is deployed and starts running. Applying the following ScaledObject:

apiVersion: keda.sh/v1alpha1
kind: ScaledObject
metadata:
  annotations:
    kubectl.kubernetes.io/last-applied-configuration: >
      {"apiVersion":"keda.sh/v1alpha1","kind":"ScaledObject","metadata":{"annotations":{"scaledobject.keda.sh/transfer-hpa-ownership":"true"},"labels":{"app":"apollo","app.kubernetes.io/instance":"apollo"},"name":"apollo","namespace":"apollo"},"spec":{"advanced":{"horizontalPodAutoscalerConfig":{"behavior":{"scaleDown":{"policies":[{"periodSeconds":60,"type":"Pods","value":1}],"stabilizationWindowSeconds":120},"scaleUp":{"policies":[{"periodSeconds":45,"type":"Pods","value":2}],"stabilizationWindowSeconds":60}},"name":"apollo"}},"fallback":{"failureThreshold":3,"replicas":1},"maxReplicaCount":10,"minReplicaCount":1,"scaleTargetRef":{"apiVersion":"argoproj.io/v1alpha1","kind":"Rollout","name":"apollo"},"triggers":[{"metadata":{"adminURL":"{url}","isPartitionedTopic":"false","msgBacklogThreshold":"5","subscription":"apollo","topic":"{topic}"},"type":"pulsar"}]}}
    scaledobject.keda.sh/transfer-hpa-ownership: 'true'
  creationTimestamp: '2023-12-08T15:59:58Z'
  finalizers:
    - finalizer.keda.sh
  generation: 3
  labels:
    app: apollo
    app.kubernetes.io/instance: apollo
    scaledobject.keda.sh/name: apollo
  name: apollo
  namespace: apollo
  resourceVersion: '294765183'
  uid: b2a6151b-aa7b-4306-8345-b3a6468fdc0f
spec:
  advanced:
    horizontalPodAutoscalerConfig:
      behavior:
        scaleDown:
          policies:
            - periodSeconds: 60
              type: Pods
              value: 1
          stabilizationWindowSeconds: 120
        scaleUp:
          policies:
            - periodSeconds: 45
              type: Pods
              value: 2
          stabilizationWindowSeconds: 60
      name: apollo
    scalingModifiers: {}
  fallback:
    failureThreshold: 3
    replicas: 1
  maxReplicaCount: 10
  minReplicaCount: 1
  scaleTargetRef:
    apiVersion: argoproj.io/v1alpha1
    kind: Rollout
    name: apollo
  triggers:
    - metadata:
        adminURL: 'http://{url}'
        isPartitionedTopic: 'false'
        msgBacklogThreshold: '5'
        subscription: apollo
        topic: 'persistent://{topic}'
      type: pulsar
status:
  conditions:
    - message: ScaledObject is defined correctly and is ready for scaling
      reason: ScaledObjectReady
      status: 'True'
      type: Ready
    - status: Unknown
      type: Active
    - status: Unknown
      type: Fallback
    - status: Unknown
      type: Paused
  externalMetricNames:
    - s0-pulsar-persistent---{topic}
  hpaName: apollo
  originalReplicaCount: 1
  scaleTargetGVKR:
    group: argoproj.io
    kind: Rollout
    resource: rollouts
    version: v1alpha1
  scaleTargetKind: argoproj.io/v1alpha1.Rollout

makes the operator crash showing the following logs:

panic: runtime error: invalid memory address or nil pointer dereference                                                                                                                                            │
│ [signal SIGSEGV: segmentation violation code=0x1 addr=0x78 pc=0x35a419c]                                                                                                                                           │
│                                                                                                                                                                                                                    │
│ goroutine 288 [running]:                                                                                                                                                                                           │
│ github.com/kedacore/keda/v2/pkg/scalers.(*pulsarScaler).GetStats(0xc000cb0ab0, {0x49fb048, 0xc0002a54f0})                                                                                                          │
│     /workspace/pkg/scalers/pulsar_scaler.go:247 +0x13c                                                                                                                                                             │
│ github.com/kedacore/keda/v2/pkg/scalers.(*pulsarScaler).getMsgBackLog(0xc000cb0ab0, {0x49fb048?, 0xc0002a54f0?})                                                                                                   │
│     /workspace/pkg/scalers/pulsar_scaler.go:287 +0x46                                                                                                                                                              │
│ github.com/kedacore/keda/v2/pkg/scalers.(*pulsarScaler).GetMetricsAndActivity(0xc000cb0ab0, {0x49fb048?, 0xc0002a54f0?}, {0xc0011e40f0, 0x41})                                                                     │
│     /workspace/pkg/scalers/pulsar_scaler.go:303 +0x56                                                                                                                                                              │
│ github.com/kedacore/keda/v2/pkg/scaling/cache.(*ScalersCache).GetMetricsAndActivityForScaler(0xc000cff7c0, {0x49fb048, 0xc0002a54f0}, 0x0, {0xc0011e40f0, 0x41})                                                   │
│     /workspace/pkg/scaling/cache/scalers_cache.go:129 +0x191                                                                                                                                                       │
│ github.com/kedacore/keda/v2/pkg/scaling.(*scaleHandler).getScalerState(0x58, {0x49fb048, 0xc0002a54f0}, {0x49ea470?, 0xc000cb0ab0}, 0xc0006d9b00?, {{0xc000eb9050, 0x6}, {0xc000eb9056, 0x6}, ...}, ...)           │
│     /workspace/pkg/scaling/scale_handler.go:699 +0x3dc                                                                                                                                                             │
│ github.com/kedacore/keda/v2/pkg/scaling.(*scaleHandler).getScaledObjectState(0x0?, {0x49fb048, 0xc0002a54f0}, 0xc000743e00)                                                                                        │
│     /workspace/pkg/scaling/scale_handler.go:590 +0x969                                                                                                                                                             │
│ github.com/kedacore/keda/v2/pkg/scaling.(*scaleHandler).checkScalers(0xc00032f730, {0x49fb048, 0xc0002a54f0}, {0x42a3720?, 0xc000743e00?}, {0x49e5128, 0xc0011c62a0})                                              │
│     /workspace/pkg/scaling/scale_handler.go:241 +0x271                                                                                                                                                             │
│ github.com/kedacore/keda/v2/pkg/scaling.(*scaleHandler).startScaleLoop(0x0?, {0x49fb048, 0xc0002a54f0}, 0xc0007048c0, {0x42a3720, 0xc000743e00}, {0x49e5128, 0xc0011c62a0}, 0x0?)                                  │
│     /workspace/pkg/scaling/scale_handler.go:180 +0x446                                                                                                                                                             │
│ created by github.com/kedacore/keda/v2/pkg/scaling.(*scaleHandler).HandleScalableObject                                                                                                                            │
│     /workspace/pkg/scaling/scale_handler.go:126 +0x55d

The access to Pulsar needs to be authless so saw no point in specifying it.

Expected Behavior

The ScaledObject to be succesfully submitted and keda operator keeps running.

Actual Behavior

Keda crashes.

Steps to Reproduce the Problem

Submit a ScaledObject with pulsar scaler without providing authModes parameter.

Logs from KEDA operator

No response

KEDA Version

2.12.0

Kubernetes Version

None

Platform

Amazon Web Services

Scaler Details

Apache Pulsar

Anything else?

Kubernetes v1.28