HPA trait definition for Medium blog on KubeVela

vela-hpa-traitdefinition.yaml

apiVersion: core.oam.dev/v1beta1
kind: TraitDefinition
metadata:
  annotations:
    definition.oam.dev/description: "configure k8s Horizontal Pod Autoscaler for Component which using Deployment as worklaod"
  name: hpa
spec:
  appliesToWorkloads:
    - deployments.apps
  workloadRefPath: spec.scaleTargetRef
  schematic:
    cue:
      template: |
        outputs: hpa: {
          apiVersion: "autoscaling/v2beta2"
          kind:       "HorizontalPodAutoscaler"
          spec: {
            minReplicas: parameter.min
            maxReplicas: parameter.max
            metrics: [{
              type: "Resource"
              resource: {
                name: "cpu"
                target: {
                  type:               "Utilization"
                  averageUtilization: parameter.cpuUtil
                }
              }
            }]
          }
        }
        parameter: {
          min:     *1 | int
          max:     *10 | int
          cpuUtil: *50 | int
        }