Extend document interface with utility methods

* GetGroup, GetVersion and GetKind now can be used to construct GVK
  structs
* ToObject deserialize document to a particular object. This is
  needed to precess custom resources which were defined for airship

Change-Id: I527e2c73288e865455853c5553bffd508a2d2eb6

pkg/document/document.go

@@ -16,6 +16,7 @@ package document
 
 import (
 	"sigs.k8s.io/kustomize/api/resource"
+	"sigs.k8s.io/yaml"
 )
 
 // Factory holds document data
@@ -30,6 +31,7 @@ type Document interface {
 	GetAnnotations() map[string]string
 	GetBool(path string) (bool, error)
 	GetFloat64(path string) (float64, error)
+	GetGroup() string
 	GetInt64(path string) (int64, error)
 	GetKind() string
 	GetLabels() map[string]string
@@ -40,8 +42,10 @@ type Document interface {
 	GetString(path string) (string, error)
 	GetStringMap(path string) (map[string]string, error)
 	GetStringSlice(path string) ([]string, error)
+	GetVersion() string
 	Label(map[string]string)
 	MarshalJSON() ([]byte, error)
+	ToObject(interface{}) error
 }
 
 // Factory implements Document
@@ -145,6 +149,18 @@ func (d *Factory) GetName() string {
 	return r.GetName()
 }
 
+// GetGroup returns api group from apiVersion field
+func (d *Factory) GetGroup() string {
+	r := d.GetKustomizeResource()
+	return r.GetGvk().Group
+}
+
+// GetVersion returns api version from apiVersion field
+func (d *Factory) GetVersion() string {
+	r := d.GetKustomizeResource()
+	return r.GetGvk().Version
+}
+
 // GetKind returns the Kind: field from the document.
 func (d *Factory) GetKind() string {
 	r := d.GetKustomizeResource()
@@ -162,6 +178,15 @@ func (d *Factory) SetKustomizeResource(r *resource.Resource) error {
 	return nil
 }
 
+// ToObject serializes document to object passed as an argument
+func (d *Factory) ToObject(obj interface{}) error {
+	docYAML, err := d.AsYAML()
+	if err != nil {
+		return err
+	}
+	return yaml.Unmarshal(docYAML, obj)
+}
+
 // NewDocument is a convenience method to construct a new Document.  Although
 // an error is unlikely at this time, this provides some future proofing for
 // when we want more strict airship specific validation of documents getting

pkg/document/document_test.go

@@ -83,6 +83,25 @@ func TestDocument(t *testing.T) {
 		assert.Equal(strings.TrimRight(s, "\n"), strings.TrimRight(string(fileData), "\n"))
 	})
 
+	t.Run("ToObject", func(t *testing.T) {
+		expectedObj := map[string]interface{}{
+			"apiVersion": "airshipit.org/v1alpha1",
+			"kind":       "Phase",
+			"metadata": map[string]interface{}{
+				"name": "initinfra",
+			},
+			"config": map[string]interface{}{
+				"documentEntryPoint": "manifests/site/test-site/initinfra",
+			},
+		}
+		doc, err := bundle.GetByName("initinfra")
+		require.NoError(err)
+		actualObj := make(map[string]interface{})
+		err = doc.ToObject(&actualObj)
+		assert.NoError(err)
+		assert.Equal(expectedObj, actualObj)
+	})
+
 	t.Run("GetString", func(t *testing.T) {
 		doc, err := bundle.GetByName("some-random-deployment-we-will-filter")
 		require.NoError(err, "Unexpected error trying to GetByName")

pkg/document/testdata/common/custom_resource.yaml

@@ -0,0 +1,7 @@
+---
+apiVersion: airshipit.org/v1alpha1
+kind: Phase
+metadata:
+  name: initinfra
+config:
+  documentEntryPoint: "manifests/site/test-site/initinfra"

pkg/document/testdata/common/kustomization.yaml

@@ -2,4 +2,5 @@ resources:
  - baremetal.yaml
  - tiller.yaml
  - argo.yaml
- - initially_ignored.yaml
+ - initially_ignored.yaml
+ - custom_resource.yaml