example.yaml

apiVersion: discovery.knative.dev/v1alpha1
kind: DuckType
metadata:
  name: addressable.duck.knative.dev
spec:
  # selectors is a list of CRD label selectors to find CRDs that have been
  # labeled as the given duck type.
  selectors:
    - selector: "duck.knative.dev/addressable=true"

  # refs allows for adding native types, or crds directly as the ducks via
  # Group/Version/Kind/Resource
  refs:
    - version: v1
      resource: services
      kind: Service

  # Names allows us to give a short name to the duck type.
  names:
    plural: addressables
    singular: addressable

  # additionalPrinterColumns is intended to understand what printer columns
  # should be used for the custom objects.
  additionalPrinterColumns:
    - name: Ready
      type: string
      JSONPath: ".status.conditions[?(@.type=='Ready')].status"
    - name: Reason
      type: string
      JSONPath: ".status.conditions[?(@.type=='Ready')].reason"
    - name: URL
      type: string
      JSONPath: .status.address.url
    - name: Age
      type: date
      JSONPath: .metadata.creationTimestamp

  # schema is the partial schema of the duck type.
  schema:
    openAPIV3Schema:
      properties:
        status:
          type: object
          properties:
            address:
              type: object
              properties:
                url:
                  type: string