This is Work in Progress. It is based on the Discovery API design doc.
ko apply -f ./configThe goal is to have a custom type that is use installable to help a developer, cluster admin, or tooling to better understand the duck types that are installed in the cluster. This information could be used to understand which Kinds could fulfill a role for another resource.
apiVersion: discovery.knative.dev/v1alpha1
kind: ClusterDuckType
metadata:
name: addressables.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:
- labelSelector: "duck.knative.dev/addressable=true"
# Names allows us to give a short name to the duck type.
names:
name: "Addressable"
plural: "addressables"
singular: "addressable"
# Versions are to allow the definition of a single duck type with multiple
# versions, useful if the duck type API shape changes.
versions:
- name: "v1"
# refs allows for adding native types, or crds directly as the ducks via
# Group/Version/Kind/Resource
refs:
- version: v1
resource: services
kind: Service
# 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
group: duck.knative.devAfter applying this, you can fetch it:
$ kubectl get ducktypes addressables.duck.knative.dev
NAME SHORT NAME DUCKS READY REASON
addressables.duck.knative.dev addressable 11 TrueAnd get the full DuckType addressable.duck.knative.dev resource:
(note this is pending finalization)
$ kubectl get clusterducktypes addressable.duck.knative.dev -oyaml
apiVersion: discovery.knative.dev/v1alpha1
kind: CluserDuckType
metadata:
generation: 1
name: addressables.duck.knative.dev
spec:
...
status:
conditions:
- lastTransitionTime: "2020-01-16T22:13:24Z"
status: "True"
type: Ready
duckCount: 10
ducks:
- group: eventing.knative.dev
kind: Broker
resource: brokers
version: v1
- group: flows.knative.dev
kind: Parallel
resource: parallels
version: v1
- group: flows.knative.dev
kind: Sequence
resource: sequences
version: v1
- group: messaging.knative.dev
kind: Channel
resource: channels
version: v1
- group: messaging.knative.dev
kind: InMemoryChannel
resource: inmemorychannels
version: v1
- group: messaging.knative.dev
kind: Parallel
resource: parallels
version: v1
- group: messaging.knative.dev
kind: Sequence
resource: sequences
version: v1
- kind: Service
resource: services
version: v1
- group: serving.knative.dev
kind: Route
resource: routes
version: v1alpha1
- group: serving.knative.dev
kind: Service
resource: services
version: v1
observedGeneration: 1If the ./config/knative directory is applied (via
kubectl apply -f config/knative), a quick view of the duck types that are on
the cluster becomes easier to get:
(note this is pending finalization)
$ kubectl get clusterducktypes
NAME DUCK NAME DUCKS READY REASON
addressables.duck.knative.dev Addressable 10 True
bindings.duck.knative.dev Binding 2 True
podspecables.duck.knative.dev PodSpecable 7 True
sources.duck.knative.dev Source 7 True
subscribables.messaging.knative.dev Subscribable 2 True