Create empty backup directory when mirror directory is empty

Signed-off-by: Philip Laine <philip.laine@gmail.com>

CHANGELOG.md

@@ -18,6 +18,7 @@ and this project adheres to [Semantic Versioning](https://semver.org/spec/v2.0.0
 ### Fixed
 
 - [#603](https://github.com/spegel-org/spegel/pull/603) Fix append to backup always happening.
+- [#604](https://github.com/spegel-org/spegel/pull/604) Create empty backup directory when mirror directory is empty.
 
 ### Security
 

pkg/oci/containerd.go

@@ -410,20 +410,17 @@ func validateRegistries(urls []url.URL) error {
 
 func backupConfig(log logr.Logger, fs afero.Fs, configPath string) error {
 	backupDirPath := path.Join(configPath, backupDir)
-	_, err := fs.Stat(backupDirPath)
-	if err != nil && !os.IsNotExist(err) {
+	ok, err := afero.DirExists(fs, backupDirPath)
+	if err != nil {
 		return err
 	}
-	if err == nil {
+	if ok {
 		return nil
 	}
 	files, err := afero.ReadDir(fs, configPath)
 	if err != nil {
 		return err
 	}
-	if len(files) == 0 {
-		return nil
-	}
 	err = fs.MkdirAll(backupDirPath, 0o755)
 	if err != nil {
 		return err

pkg/oci/containerd_test.go

@@ -10,6 +10,7 @@ import (
 
 	eventtypes "github.com/containerd/containerd/api/events"
 	"github.com/containerd/typeurl/v2"
+	"github.com/go-logr/logr"
 	"github.com/spf13/afero"
 	"github.com/stretchr/testify/require"
 	runtimeapi "k8s.io/cri-api/pkg/apis/runtime/v1"
@@ -92,6 +93,38 @@ func TestVerifyStatusResponse(t *testing.T) {
 	}
 }
 
+func TestBackupConfig(t *testing.T) {
+	t.Parallel()
+
+	log := logr.Discard()
+
+	fs := afero.NewMemMapFs()
+	err := fs.MkdirAll("/config", 0o755)
+	require.NoError(t, err)
+	err = backupConfig(log, fs, "/config")
+	require.NoError(t, err)
+	ok, err := afero.DirExists(fs, "/config/_backup/")
+	require.NoError(t, err)
+	require.True(t, ok)
+	files, err := afero.ReadDir(fs, "/config/_backup")
+	require.NoError(t, err)
+	require.Empty(t, files)
+
+	fs = afero.NewMemMapFs()
+	err = fs.MkdirAll("/config", 0o755)
+	require.NoError(t, err)
+	err = afero.WriteFile(fs, "/config/test.txt", []byte("Hello World"), 0o644)
+	require.NoError(t, err)
+	err = backupConfig(log, fs, "/config/")
+	require.NoError(t, err)
+	ok, err = afero.DirExists(fs, "/config/_backup/")
+	require.NoError(t, err)
+	require.True(t, ok)
+	files, err = afero.ReadDir(fs, "/config/_backup/")
+	require.NoError(t, err)
+	require.Len(t, files, 1)
+}
+
 func TestCreateFilter(t *testing.T) {
 	t.Parallel()
 
@@ -450,11 +483,9 @@ capabilities = ['pull', 'resolve']`,
 			}
 			err := AddMirrorConfiguration(context.TODO(), fs, registryConfigPath, tt.registries, tt.mirrors, tt.resolveTags, tt.appendToBackup)
 			require.NoError(t, err)
-			if len(tt.existingFiles) == 0 {
-				ok, err := afero.DirExists(fs, "/etc/containerd/certs.d/_backup")
-				require.NoError(t, err)
-				require.False(t, ok)
-			}
+			ok, err := afero.DirExists(fs, "/etc/containerd/certs.d/_backup")
+			require.NoError(t, err)
+			require.True(t, ok)
 			err = afero.Walk(fs, registryConfigPath, func(path string, fi iofs.FileInfo, _ error) error {
 				if fi.IsDir() {
 					return nil