Kustomize Generator

A resource generator for kustomizations

This generator allows to generate the manifests of the component’s resources from a given kustomization. As a special case, one or more simple Kubernetes manifests (without a kustomization.yaml) are supported as well. In addition, all (or selected; see below) files in the kustomization directory can be templatized in a helm’ish way. That means, they will be considered as a common template group (where all templates are associated with each other), and the same template function set that is available on Helm can be used; so, all the sprig functions, and custom functions such as include, tpl, lookup can be used. In addition:

  • parameterless functions namespace and name are defined, which return the corresponding arguments passed to Generate()
  • a function kubernetesVersion is available, which returns the version information of the target cluster, as a version.Info structure.

In the generation step, first, all the go templates will be rendered, and the result of this pre-step will be passed to kustomize.

A kustomize generator can be instantiated by calling the following constructor:

package kustomize

func NewKustomizeGenerator(
  fsys fs.FS,
  kustomizationPath string,
  templateSuffix string,
  client client.Client
) (*KustomizeGenerator, error) {

Here:

  • fsys must be an implementation of fs.FS, such as embed.FS; or it can be passed as nil; then, all file operations will be executed on the current OS filesystem.
  • kustomizationPath is the directory containing the (potentially templatized) kustomatization; if fsys was provided, this has to be a relative path; otherwise, it will be interpreted with respect to the OS filesystem (as an absolute path, or relative to the current working directory of the controller).
  • templateSuffx is optional; if empty, all files under kustomizationPath will be subject to go templating; otherwise, only files matching the specified suffix will be considered as templates.
  • client should be a client for the local cluster (i.e. the cluster where the component object exists).

As of now, the specified kustomization must not reference files or paths outside kustomizationPath. Remote references are generally not supported.