This is Work in Progress.
ko apply -f ./config
The 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: 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
After applying this, you can fetch it:
$ kubectl get ducktypes addressable.duck.knative.dev
NAME SHORT NAME DUCKS READY REASON
addressable.duck.knative.dev addressable 11 True
And get the full DuckType addressable.duck.knative.dev
resource:
$ kubectl get ducktypes addressable.duck.knative.dev -oyaml
apiVersion: discovery.knative.dev/v1alpha1
kind: DuckType
metadata:
generation: 1
name: addressable.duck.knative.dev
spec:
additionalPrinterColumns:
- JSONPath: .status.conditions[?(@.type=='Ready')].status
name: Ready
type: string
- JSONPath: .status.conditions[?(@.type=='Ready')].reason
name: Reason
type: string
- JSONPath: .status.address.url
name: URL
type: string
- JSONPath: .metadata.creationTimestamp
name: Age
type: date
names:
plural: addressables
singular: addressable
refs:
- kind: Service
resource: services
version: v1
schema:
openAPIV3Schema:
properties:
status:
properties:
address:
properties:
url:
type: string
type: object
type: object
selectors:
- selector: duck.knative.dev/addressable=true
status:
conditions:
- lastTransitionTime: "2020-01-16T22:13:24Z"
status: "True"
type: Ready
duckCount: 11
ducks:
- group: eventing.knative.dev
kind: Broker
resource: brokers
version: v1alpha1
- group: flows.knative.dev
kind: Parallel
resource: parallels
version: v1alpha1
- group: flows.knative.dev
kind: Sequence
resource: sequences
version: v1alpha1
- group: messaging.knative.dev
kind: Channel
resource: channels
version: v1alpha1
- group: messaging.knative.dev
kind: InMemoryChannel
resource: inmemorychannels
version: v1alpha1
- group: messaging.knative.dev
kind: Parallel
resource: parallels
version: v1alpha1
- group: messaging.knative.dev
kind: Sequence
resource: sequences
version: v1alpha1
- group: n3wscott.com
kind: Task
resource: tasks
version: v1alpha1
- 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: v1alpha1
observedGeneration: 1
If the ./condif/knative
directory is applied, a quick view of the duck types that are on the cluster becomes easier to get:
$ kubectl get ducktypes
NAME SHORT NAME DUCKS READY REASON
addressable.duck.knative.dev addressable 11 True
binding.duck.knative.dev binding 2 True
podspecable.duck.knative.dev podspecable 7 True
source.duck.knative.dev source 7 True
subscribable.messaging.knative.dev subscribable 2 True