This is an example of implementing a validation function against kubeval.

The function is implemented as an image, and built using make image.

The function is implemented as a go program, which reads a collection of input Resource configuration, passing each to kubeval.

A number of settings can be modified for kubeval in the function spec. See the API struct definition in main.go for documentation.

The function is invoked by authoring a local Resource with metadata.annotations.[config.kubernetes.io/function] and running:

kustomize fn run local-resource/

This exists non-zero if kubeval detects an invalid Resource.

Run the validator with:

kustomize fn run local-resource/

This will return an error:

Resource invalid: (Kind: Service, Name: svc)
prots: Additional property prots is not allowed
Error: exit status 1

Now fix the typo in example-use.yaml and run:

kustomize fn run local-resource/

This will return success (no output).