adding_defaulting.md

Adding a value defaulting to a resources schema

To add server side field value defaulting for your resource implement the interface var _ resourcestrategy.Defaulter = &<Kind>{} in the type definition file. Specifically the defaulter interface lies in the package sigs.k8s.io/apiserver-runtime/pkg/builder/resource/resourcestrategy.

Example:

File: pkg/apis/<group>/<version>/<kind>_types.go

var _ resourcestrategy.Defaulter = &Foo{}

func (in *Foo) Default() {
	if in.Spec.Field == nil {
		f := "value"
		in.Spec.Field = &f
	}
}

Anatomy of defaulting

By default, the apiserver-boot won't generate defaulter related codes for you. You're supposed to manually add the interface assertion and implementation.

---

Update set values for fields with nil values.

	if in.Spec.Field == nil {
		f := "value"
		in.Spec.Field = &f
	}