Do not try to create an audit log file named "-"

That PR fixes --audit-log-path=- support.
It now logs to stdout as in 1.21.

staging/src/k8s.io/apiserver/pkg/server/options/audit.go

@@ -511,21 +511,21 @@ func (o *AuditLogOptions) getWriter() (io.Writer, error) {
 		return nil, nil
 	}
 
-	if err := o.ensureLogFile(); err != nil {
+	if o.Path == "-" {
-		return nil, err
+		return os.Stdout, nil
 	}
 
-	var w io.Writer = os.Stdout
+	if err := o.ensureLogFile(); err != nil {
-	if o.Path != "-" {
+		return nil, fmt.Errorf("ensureLogFile: %w", err)
-		w = &lumberjack.Logger{
-			Filename:   o.Path,
-			MaxAge:     o.MaxAge,
-			MaxBackups: o.MaxBackups,
-			MaxSize:    o.MaxSize,
-			Compress:   o.Compress,
-		}
 	}
-	return w, nil
+
+	return &lumberjack.Logger{
+		Filename:   o.Path,
+		MaxAge:     o.MaxAge,
+		MaxBackups: o.MaxBackups,
+		MaxSize:    o.MaxSize,
+		Compress:   o.Compress,
+	}, nil
 }
 
 func (o *AuditLogOptions) ensureLogFile() error {

staging/src/k8s.io/apiserver/pkg/server/options/audit_test.go

@@ -27,6 +27,7 @@ import (
 	"github.com/spf13/pflag"
 	"github.com/stretchr/testify/assert"
 	"github.com/stretchr/testify/require"
+	"gopkg.in/natefinch/lumberjack.v2"
 	metav1 "k8s.io/apimachinery/pkg/apis/meta/v1"
 	auditv1 "k8s.io/apiserver/pkg/apis/audit/v1"
 	"k8s.io/apiserver/pkg/server"
@@ -59,6 +60,15 @@ func TestAuditValidOptions(t *testing.T) {
 			return o
 		},
 		expected: "ignoreErrors<log>",
+	}, {
+		name: "stdout log",
+		options: func() *AuditOptions {
+			o := NewAuditOptions()
+			o.LogOptions.Path = "-"
+			o.PolicyFile = policy
+			return o
+		},
+		expected: "ignoreErrors<log>",
 	}, {
 		name: "default log no policy",
 		options: func() *AuditOptions {
@@ -147,6 +157,22 @@ func TestAuditValidOptions(t *testing.T) {
 			} else {
 				assert.Equal(t, tc.expected, fmt.Sprintf("%s", config.AuditBackend))
 			}
+
+			w, err := options.LogOptions.getWriter()
+			require.NoError(t, err, "Writer creation should not fail.")
+
+			// Don't check writer if logging is disabled.
+			if w == nil {
+				return
+			}
+
+			if options.LogOptions.Path == "-" {
+				assert.Equal(t, os.Stdout, w)
+				assert.NoFileExists(t, options.LogOptions.Path)
+			} else {
+				assert.IsType(t, (*lumberjack.Logger)(nil), w)
+				assert.FileExists(t, options.LogOptions.Path)
+			}
 		})
 	}
 }