feat(understackctl): deploy check uses kustomize build to validate

[cardoe]

Validate the manifests by running 'kustomize build' against each enabled
component.

[skrobul]

This works, but I was wondering what do you think about not relying on the kustomize binary to be present on the system and running kustomize natively instead?

import (
	"fmt"
	"path/filepath"
	"sigs.k8s.io/kustomize/api/krusty"
	kusttypes "sigs.k8s.io/kustomize/api/types"
	"sigs.k8s.io/kustomize/kyaml/filesys"
)
// validateKustomizationNative runs the equivalent of:
// kustomize build --enable-alpha-plugins --enable-exec --enable-helm --load-restrictor LoadRestrictionsNone <compDir>
func validateKustomizationNative(compDir string) error {
	opts := krusty.MakeDefaultOptions()
	// --load-restrictor LoadRestrictionsNone
	opts.LoadRestrictions = kusttypes.LoadRestrictionsNone
	// --enable-alpha-plugins + --enable-helm
	opts.PluginConfig = kusttypes.EnabledPluginConfig(kusttypes.BploLoadFromFileSys)
	opts.PluginConfig.HelmConfig.Command = "helm"
	// --enable-exec (for function plugins)
	opts.PluginConfig.FnpLoadingOptions.EnableExec = true
	k := krusty.MakeKustomizer(opts)
	if _, err := k.Run(filesys.MakeFsOnDisk(), compDir); err != nil {
		return fmt.Errorf("%s: %w", filepath.Join(compDir, "kustomization.yaml"), err)
	}
	return nil
}

And in runDeployCheck, replace the `exec.Command(...) with:

if err := validateKustomizationNative(compDir); err != nil {
	kustomizeErrors = append(kustomizeErrors, err.Error())
}

the import block will need:

	"sigs.k8s.io/kustomize/api/krusty"
	kusttypes "sigs.k8s.io/kustomize/api/types"
	"sigs.k8s.io/kustomize/kyaml/filesys"

the docs:
https://pkg.go.dev/sigs.k8s.io/kustomize/api/krusty
https://pkg.go.dev/sigs.k8s.io/kustomize/api/types

[cardoe]

That's probably better