replica-count-check.yaml

apiVersion: kubevious.io/v1alpha1
kind: ClusterRule
metadata:
  name: replica-count-check
spec:
  summary: |
    Checks Deployments to have min/max replicas - with or without HPAs.
  categories:
    - k8s
    - deployment
    - replica-count
  values:
    minReplicas: 1
    maxReplicas: 1000
  target: |
    Union(
      Api('apps')
        .Kind('Deployment'),
      Api('argoproj.io')
        .Kind('Rollout')
    )
  rule: |
    const hpa = findHPA();
    if (hpa)
    {
      const minReplicas = hpa.config.spec?.minReplicas ?? 1;
      if (values.minReplicas)
      {
        if (minReplicas < values.minReplicas)
        {
          error(`HPA ${hpa.name} minReplicas should be at least ${values.minReplicas}`);
        }
      }
      if (values.maxReplicas)
      {
        const maxReplicas = hpa.config.spec?.maxReplicas ?? minReplicas;
        if (maxReplicas > values.maxReplicas)
        {
          error(`HPA ${hpa.name} maxReplicas should be at most ${values.maxReplicas}`);
        }
      }
    }
    else
    {
      const replicas = config.spec?.replicas ?? 1;
      if (values.minReplicas)
      {
        if (replicas < values.minReplicas)
        {
          error(`Replica count should be at least ${values.minReplicas}`);
        }
      }
      if (values.maxReplicas)
      {
        if (replicas > values.maxReplicas)
        {
          error(`Replica count should be at most ${values.maxReplicas}`);
        }
      }
    }
    
    function findHPA()
    {
      for(const hpa of Api('autoscaling')
                        .Kind('HorizontalPodAutoscaler')
                        .many())
      {
        const scaleTargetRef = hpa.config?.spec?.scaleTargetRef;
        if (scaleTargetRef)
        {
          if (scaleTargetRef.apiVersion === item.apiVersion && 
              scaleTargetRef.kind === item.kind && 
              scaleTargetRef.name === item.name)
          {
            return hpa;
          }
        }
      }
      return null;
    }
  application:
    useApplicator: true