Add ability to create bundle from bytes

This patch implements new constructor of document.Bundle type
using raw bytes as source.

Change-Id: Ie7742bcf245083ac988541aa9987448f5827fec3
Signed-off-by: Ruslan Aliev <raliev@mirantis.com>

pkg/document/bundle.go

@@ -18,6 +18,7 @@ import (
 	"io"
 	"strings"
 
+	kustfs "sigs.k8s.io/kustomize/api/filesys"
 	"sigs.k8s.io/kustomize/api/k8sdeps/kunstruct"
 	"sigs.k8s.io/kustomize/api/krusty"
 	"sigs.k8s.io/kustomize/api/resmap"
@@ -68,6 +69,21 @@ func NewBundleByPath(rootPath string) (Bundle, error) {
 	return NewBundle(fs.NewDocumentFs(), rootPath)
 }
 
+// NewBundleFromBytes is a function which builds new document.Bundle from raw []bytes
+func NewBundleFromBytes(data []byte) (Bundle, error) {
+	fSys := fs.Fs{
+		FileSystem: kustfs.MakeFsInMemory(),
+	}
+	if err := fSys.WriteFile("/kustomization.yaml", []byte(`resources:
+- data.yaml`)); err != nil {
+		return nil, err
+	}
+	if err := fSys.WriteFile("/data.yaml", data); err != nil {
+		return nil, err
+	}
+	return NewBundle(fSys, "/")
+}
+
 // NewBundle is a convenience function to create a new bundle
 // Over time, it will evolve to support allowing more control
 // for kustomize plugins
@@ -101,7 +117,7 @@ func NewBundle(fSys fs.FileSystem, kustomizePath string) (Bundle, error) {
 	kustomizer := krusty.MakeKustomizer(fSys, &o)
 	m, err := kustomizer.Run(kustomizePath)
 	if err != nil {
-		return bundle, err
+		return nil, err
 	}
 	err = bundle.SetKustomizeResourceMap(m)
 	return bundle, err

pkg/document/bundle_test.go

@@ -32,6 +32,32 @@ func TestNewBundle(t *testing.T) {
 	require.NotNil(bundle)
 }
 
+func TestNewBundleFromBytes(t *testing.T) {
+	require := require.New(t)
+	assert := assert.New(t)
+
+	bundle, err := document.NewBundleFromBytes([]byte(`apiVersion: v1
+kind: Test
+metadata:
+ name: test
+ labels:
+   app: test-label`))
+	require.NoError(err)
+	require.NotNil(bundle)
+
+	docs, err := bundle.GetAllDocuments()
+	require.NoError(err)
+	assert.NotEmpty(docs)
+
+	doc, err := bundle.SelectOne(document.NewSelector().ByKind("Test").ByName("test"))
+	require.NoError(err)
+	assert.NotNil(doc)
+
+	doc, err = bundle.SelectOne(document.NewSelector().ByKind("Test").ByLabel("app"))
+	require.NoError(err)
+	assert.NotNil(doc)
+}
+
 func TestBundleDocumentFiltering(t *testing.T) {
 	assert := assert.New(t)
 	require := require.New(t)