# Append Application CR This is an example of appending an Application CR to a group of resources. This example is written in `go` and uses the `kyaml` libraries for parsing the input and writing the output. Writing in `go` is not a requirement. ## Function implementation The function is implemented as an [image](image), and built using `make image`. The template is implemented as a go program, which reads a collection of input Resource configuration, and looks for invalid configuration. ## Function invocation The function is invoked by authoring a [local Resource](local-resource) with `metadata.annotations.[config.kubernetes.io/function]` and running: kustomize fn run local-resource/ --fn-path config/ This exits non-zero if there is an error. ## Running the Example Run the validator with: kustomize fn run local-resource/ --fn-path config/ This will append an Application CR.