[AIR-97] Moving WriteOut function from bundle pkg

This commit moves Write function to separate yaml package, and makes
it available to anyone for dumping documents in single file, with
correct yaml separators '---', '...'.

This will allow, for example dumping of filtered from bundle documents
to disk or any writer, like Stdout, for debugging purposes. Specifically
it will be used as part of `airshipctl cluster initinfra` command as a
buffer for delivering resources to kubernetes cluster.

Change-Id: I780e3f2d2ff446b8787153f500d04d10487ed71b

go.mod

@@ -79,7 +79,7 @@ require (
 	gotest.tools v2.2.0+incompatible // indirect
 	k8s.io/api v0.0.0-20190516230258-a675ac48af67 // indirect
 	k8s.io/apiextensions-apiserver v0.0.0-20190516231611-bf6753f2aa24 // indirect
-	k8s.io/apimachinery v0.0.0-20190404173353-6a84e37a896d // indirect
+	k8s.io/apimachinery v0.0.0-20190404173353-6a84e37a896d
 	k8s.io/apiserver v0.0.0-20190516230822-f89599b3f645 // indirect
 	k8s.io/cli-runtime v0.0.0-20190516231937-17bc0b7fcef5 // indirect
 	k8s.io/client-go v11.0.1-0.20190516230509-ae8359b20417+incompatible

pkg/document/bundle.go

@@ -15,7 +15,8 @@ import (
 	"sigs.k8s.io/kustomize/v3/pkg/resource"
 	"sigs.k8s.io/kustomize/v3/pkg/target"
 	"sigs.k8s.io/kustomize/v3/pkg/types"
-	"sigs.k8s.io/yaml"
+
+	utilyaml "opendev.org/airship/airshipctl/pkg/util/yaml"
 )
 
 // KustomizeBuildOptions contain the options for running a Kustomize build on a bundle
@@ -230,26 +231,10 @@ func (b *BundleFactory) GetByGvk(group, version, kind string) ([]Document, error
 // Write will write out the entire bundle resource map
 func (b *BundleFactory) Write(out io.Writer) error {
 	for _, res := range b.ResMap.Resources() {
-
-		yamlOut, err := yaml.Marshal(res.Map())
+		err := utilyaml.WriteOut(out, res)
 		if err != nil {
 			return err
 		}
-		// add separator for each document
-		_, err = out.Write([]byte("---\n"))
-		if err != nil {
-			return err
-		}
-		_, err = out.Write(yamlOut)
-		if err != nil {
-			return err
-		}
-		// add separator for each document
-		_, err = out.Write([]byte("...\n"))
-		if err != nil {
-			return err
-		}
-
 	}
 	return nil
 }

pkg/util/yaml/writer.go

@@ -0,0 +1,32 @@
+package yaml
+
+import (
+	"io"
+
+	"sigs.k8s.io/yaml"
+)
+
+// WriteOut dumps any yaml competible document to writer, adding yaml separator `---`
+// at the beginning of the document, and `...` at the end
+func WriteOut(dst io.Writer, src interface{}) error {
+
+	yamlOut, err := yaml.Marshal(src)
+	if err != nil {
+		return err
+	}
+	// add separator for each document
+	_, err = dst.Write([]byte("---\n"))
+	if err != nil {
+		return err
+	}
+	_, err = dst.Write(yamlOut)
+	if err != nil {
+		return err
+	}
+	// add separator for each document
+	_, err = dst.Write([]byte("...\n"))
+	if err != nil {
+		return err
+	}
+	return nil
+}

pkg/util/yaml/writer_test.go

@@ -0,0 +1,55 @@
+package yaml_test
+
+import (
+	"bytes"
+	"regexp"
+	"testing"
+	"time"
+
+	"github.com/stretchr/testify/assert"
+	metav1 "k8s.io/apimachinery/pkg/apis/meta/v1"
+	"sigs.k8s.io/yaml"
+
+	utilyaml "opendev.org/airship/airshipctl/pkg/util/yaml"
+)
+
+func TestWriteOut(t *testing.T) {
+
+	// Create some object, that can be marshaled into yaml
+	ob := &metav1.ObjectMeta{
+		Name:              "RandomName",
+		Namespace:         "uniqueNamespace",
+		CreationTimestamp: metav1.NewTime(time.Unix(10, 0)),
+		Labels: map[string]string{
+			"airshiplabel": "airshipit.org",
+			"app":          "foo",
+		},
+	}
+
+	var b bytes.Buffer
+
+	// WriteOut to buffer
+	err := utilyaml.WriteOut(&b, ob)
+	if err != nil {
+		t.Fatalf("Failed to write out yaml: %v", err)
+	}
+
+	// Verify result contents
+	// TODO (kkalynovskyi) make more reliable tests
+	assert.Contains(t, b.String(), ob.Name)
+	assert.Contains(t, b.String(), "airshiplabel: airshipit.org")
+	assert.Regexp(t, regexp.MustCompile(`^---.*`), b.String())
+	assert.Regexp(t, regexp.MustCompile(`.*\.\.\.\n$`), b.String())
+
+	// Create new ObjectMeta for reverse marshaling test.
+	var rob metav1.ObjectMeta
+
+	// Check if you can marshal the results of writeout back to the Object
+	err = yaml.Unmarshal(b.Bytes(), &rob)
+	if err != nil {
+		t.Fatalf("Result of write out can not be transformed back into original object: %v", err)
+	}
+
+	// Compare original object with reverse marshaled
+	assert.Equal(t, ob, &rob)
+}