Example of validated manifest

manifest.go

package manifest

import (
	"fmt"

	"github.com/stretchr/objx"
)

// Manifest describes a single Kubernetes manifest. Manifests should only ever be
// constructed using the NewManifest method, to ensure the resource is well-formed.
type Manifest struct {
	manifest
}

func NewManifest(obj map[string]interface{}) (Manifest, error) {
	if isValid(obj) {
		return Manifest{manifest(obj)}, nil
	}

	return Manifest{}, fmt.Errorf("could not construct Manifest from invalid kubernetes object")
}

// isValid attempts to infer whether the given object is a valid kubernetes resource by
// verifying the presence of apiVersion, kind and metadata.name. These three fields are
// required for kubernetes to accept any resource.
//
// In future, it might be a good idea to allow users to opt their object out of being
// interpreted as a kubernetes resource, perhaps with a field like `exclude: true`. For
// now, any object within the jsonnet output that quacks like a kubernetes resource will
// be provided to the kubernetes API.
func isValid(obj objx.Map) bool {
	return obj.Get("apiVersion").IsStr() && obj.Get("apiVersion").Str() != "" &&
		obj.Get("kind").IsStr() && obj.Get("kind").Str() != "" &&
		obj.Get("metadata.name").IsStr() && obj.Get("metadata.name").Str() != ""
}

type manifest map[string]interface{}

func (m manifest) APIVersion() string {
	return m["apiVersion"].(string)
}

func (m manifest) Kind() string {
	return m["kind"].(string)
}

func (m manifest) Name() string {
	return m["metadata"].(map[string]interface{})["name"].(string)
}

func (m manifest) Namespace() string {
	return m["metadata"].(map[string]interface{})["namespace"].(string)
}

func (m manifest) KindName() string {
	return fmt.Sprintf("%s/%s", m.Kind(), m.Name())
}

func (m manifest) GroupVersionKindName() string {
	return fmt.Sprintf("%s/%s/%s", m.APIVersion(), m.Kind(), m.Name())
}

func (m manifest) Get(key string) *objx.Value {
	return m.Objx().Get(key)
}

func (m manifest) Set(key string, value interface{}) manifest {
	return manifest(m.Objx().Set(key, value))
}

func (m manifest) Objx() objx.Map {
	return objx.New((map[string]interface{})(m))
}