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.Exists(constants.KustomizationFileName) {
+		mf.path = constants.KustomizationFileName
+	} else if mf.fSys.Exists(constants.SecondaryKustomizationFileName) {
+		mf.path = constants.SecondaryKustomizationFileName
+	} else {
+		return fmt.Errorf("Missing kustomization file '%s'.\n", constants.KustomizationFileName)
 	}
+
 	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)
-		}
-	} 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("%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

pkg/constants/constants.go

@@ -20,5 +20,12 @@ package constants
 // KustomizationFileSuffix is expected suffix for KustomizationFileName.
 const KustomizationFileSuffix = ".yaml"
 
+// SecondaryKustomizationFileSuffix is the second expected suffix when KustomizationFileSuffix is not found
+const SecondaryKustomizationFileSuffix = ".yml"
+
 // KustomizationFileName is the Well-Known File Name for a kustomize configuration file.
 const KustomizationFileName = "kustomization" + KustomizationFileSuffix
+
+// SecondaryKustomizationFileName is the secondary File Name for a kustomize configuration file when
+// KustomizationFileName is not found
+const SecondaryKustomizationFileName = "kustomization" + SecondaryKustomizationFileSuffix

pkg/target/kusttarget.go

@@ -21,17 +21,18 @@ import (
 	"bytes"
 	"encoding/json"
 	"fmt"
-	"sigs.k8s.io/kustomize/pkg/ifc"
-	"sigs.k8s.io/kustomize/pkg/resid"
+	"strings"
 
 	"github.com/ghodss/yaml"
 	"github.com/golang/glog"
 	"github.com/pkg/errors"
 	"sigs.k8s.io/kustomize/pkg/constants"
 	"sigs.k8s.io/kustomize/pkg/fs"
+	"sigs.k8s.io/kustomize/pkg/ifc"
 	"sigs.k8s.io/kustomize/pkg/ifc/transformer"
 	interror "sigs.k8s.io/kustomize/pkg/internal/error"
 	patchtransformer "sigs.k8s.io/kustomize/pkg/patch/transformer"
+	"sigs.k8s.io/kustomize/pkg/resid"
 	"sigs.k8s.io/kustomize/pkg/resmap"
 	"sigs.k8s.io/kustomize/pkg/resource"
 	"sigs.k8s.io/kustomize/pkg/transformers"
@@ -55,7 +56,7 @@ func NewKustTarget(
 	rf *resmap.Factory,
 	ptf transformer.Factory,
 	tcfg *config.TransformerConfig) (*KustTarget, error) {
-	content, err := ldr.Load(constants.KustomizationFileName)
+	content, err := loadKustFile(ldr)
 	if err != nil {
 		return nil, err
 	}
@@ -347,3 +348,16 @@ func (kt *KustTarget) getAllVars() ([]types.Var, error) {
 	}
 	return result, nil
 }
+
+func loadKustFile(ldr ifc.Loader) ([]byte, error) {
+	for _, kf := range []string{constants.KustomizationFileName, constants.SecondaryKustomizationFileName} {
+		content, err := ldr.Load(kf)
+		if err == nil {
+			return content, nil
+		}
+		if !strings.Contains(err.Error(), "no such file or directory") {
+			return nil, err
+		}
+	}
+	return nil, fmt.Errorf("no kustomization.yaml file under %s", ldr.Root())
+}