Split kubectl apply method into two methods

In some cases, we need to execute kubectl apply against raw YAML
instead of the document.
This patchset provides the ability to call ApplyDocs for Documents
and ApplyYaml for YAML.

Relates-To: #268
Change-Id: I4b61d4358ecf5b739b9957a009458ef51142c41f

pkg/k8s/kubectl/interfaces.go

@@ -23,6 +23,7 @@ import (
 // Interface provides a abstraction layer built on top of kubectl libraries
 // to implement kubectl subcommands as kubectl apply
 type Interface interface {
-	Apply(docs []document.Document, ao *ApplyOptions) error
+	ApplyDocs(docs []document.Document, ao *ApplyOptions) error
+	ApplyYaml(yaml []byte, ao *ApplyOptions) error
 	ApplyOptions() (*ApplyOptions, error)
 }

pkg/k8s/kubectl/kubectl.go

@@ -15,6 +15,7 @@
 package kubectl
 
 import (
+	"bytes"
 	"os"
 
 	"k8s.io/cli-runtime/pkg/genericclioptions"
@@ -56,8 +57,21 @@ func (kubectl *Kubectl) WithBufferDir(bd string) *Kubectl {
 	return kubectl
 }
 
-// Apply is abstraction to kubectl apply command
-func (kubectl *Kubectl) Apply(docs []document.Document, ao *ApplyOptions) error {
+// ApplyDocs transform Document into YAML
+// TODO: (anoskov) Add unit test for ApplyDocs, as of now it is calling ApplyYaml which meets the coverage test.
+func (kubectl *Kubectl) ApplyDocs(docs []document.Document, ao *ApplyOptions) error {
+	buf := bytes.NewBuffer([]byte{})
+	for _, doc := range docs {
+		err := utilyaml.WriteOut(buf, doc)
+		if err != nil {
+			return err
+		}
+	}
+	return kubectl.ApplyYaml(buf.Bytes(), ao)
+}
+
+// ApplyYaml is abstraction to kubectl apply command
+func (kubectl *Kubectl) ApplyYaml(yaml []byte, ao *ApplyOptions) error {
 	tf, err := kubectl.TempFile(kubectl.bufferDir, "initinfra")
 	if err != nil {
 		return err
@@ -70,13 +84,11 @@ func (kubectl *Kubectl) Apply(docs []document.Document, ao *ApplyOptions) error
 			log.Fatalf("Failed to cleanup temporary file %s during kubectl apply", fName)
 		}
 	}(tf)
+
 	defer tf.Close()
-	for _, doc := range docs {
-		// Write out documents to temporary file
-		err = utilyaml.WriteOut(tf, doc)
-		if err != nil {
-			return err
-		}
+	_, err = tf.Write(yaml)
+	if err != nil {
+		return err
 	}
 	ao.SetSourceFiles([]string{tf.Name()})
 	return ao.Run()

pkg/k8s/kubectl/kubectl_test.go

@@ -108,6 +108,6 @@ func TestApply(t *testing.T) {
 	}
 	for _, test := range tests {
 		kctl.FileSystem = test.fs
-		assert.Equal(t, kctl.Apply(docs, ao), test.expectedErr)
+		assert.Equal(t, kctl.ApplyDocs(docs, ao), test.expectedErr)
 	}
 }