add support .yml extension for kusotmization file

pkg/commands/kustfile/kustomizationfile.go

@@ -22,7 +22,6 @@ import (
 	"fmt"
 	"io"
 	"log"
-	"path"
 	"reflect"
 	"regexp"
 	"strings"
@@ -118,7 +117,7 @@ type kustomizationFile struct {
 
 // NewKustomizationFile returns a new instance.
 func NewKustomizationFile(fSys fs.FileSystem) (*kustomizationFile, error) { // nolint
-	mf := &kustomizationFile{path: constants.KustomizationFileName, fSys: fSys}
+	mf := &kustomizationFile{fSys: fSys}
 	err := mf.validate()
 	if err != nil {
 		return nil, err
@@ -127,19 +126,16 @@ func NewKustomizationFile(fSys fs.FileSystem) (*kustomizationFile, error) { // n
 }
 
 func (mf *kustomizationFile) validate() error {
-	if !mf.fSys.Exists(mf.path) {
-		return fmt.Errorf("Missing kustomization file '%s'.\n", mf.path)
-	}
-	if mf.fSys.IsDir(mf.path) {
-		mf.path = path.Join(mf.path, constants.KustomizationFileName)
-		if !mf.fSys.Exists(mf.path) {
-			return fmt.Errorf("Missing kustomization file '%s'.\n", mf.path)
-		}
+	if mf.fSys.Exists(constants.KustomizationFileName) {
+		mf.path = constants.KustomizationFileName
+	} else if mf.fSys.Exists(constants.SecondaryKustomizationFileName) {
+		mf.path = constants.SecondaryKustomizationFileName
 	} else {
-		if !strings.HasSuffix(mf.path, constants.KustomizationFileName) {
-			return fmt.Errorf("Kustomization file path (%s) should have %s suffix\n",
-				mf.path, constants.KustomizationFileSuffix)
-		}
+		return fmt.Errorf("Missing kustomization file '%s'.\n", constants.KustomizationFileName)
+	}
+
+	if mf.fSys.IsDir(mf.path) {
+		return fmt.Errorf("%s should be a file", mf.path)
 	}
 	return nil
 }

pkg/commands/kustfile/kustomizationfile_test.go

@@ -21,6 +21,7 @@ import (
 	"strings"
 	"testing"
 
+	"sigs.k8s.io/kustomize/pkg/constants"
 	"sigs.k8s.io/kustomize/pkg/fs"
 	"sigs.k8s.io/kustomize/pkg/types"
 )
@@ -141,6 +142,25 @@ func TestNewNotExist(t *testing.T) {
 	}
 }
 
+func TestSecondarySuffix(t *testing.T) {
+	kcontent := `
+configMapGenerator:
+- literals:
+  - foo=bar
+  - baz=qux
+  name: my-configmap
+`
+	fakeFS := fs.MakeFakeFS()
+	fakeFS.WriteFile(constants.SecondaryKustomizationFileName, []byte(kcontent))
+	k, err := NewKustomizationFile(fakeFS)
+	if err != nil {
+		t.Fatalf("Unexpected Error: %v", err)
+	}
+	if k.path != constants.SecondaryKustomizationFileName {
+		t.Fatalf("Load incorrect file path %s", k.path)
+	}
+}
+
 func TestPreserveComments(t *testing.T) {
 	kustomizationContentWithComments := []byte(
 		`# shem qing some comments