- Support specifying RunFns.Functions using the `-i` flag to specify an image
- Parse the function config from key-value arguments specified after ` -- `
- Support reading from stdin / writing to stdout if no arguments are provided
- Table driven tests for parsing flags and args into RunFns structure
As defined in `kustomize config docs-fn-spec`, configuration functions can be
implemented using any toolchain and invoked using any container workflow orchestrator
(e.g. Tekton, Cloud Build) or run directly using docker run.
functions-impl describes using `kustomize config run` as an example
orchestrator for invoking configuration functions.