vmbackupmanager: fixes for windows compatibility (#641)

* app/vmbackupmanager/storage: fix path join for windows

See: https://github.com/VictoriaMetrics/VictoriaMetrics/issues/4704

Signed-off-by: Zakhar Bessarab <z.bessarab@victoriametrics.com>

* lib/backup: fixes for windows support

- close dir before running os.RemoveAll. Windows FS does not allow to delete directory before all handles will be closed.

- add path "normalization" for local FS to use the same format of paths for both *unix and Windows

See https://github.com/VictoriaMetrics/VictoriaMetrics/issues/4704

Signed-off-by: Zakhar Bessarab <z.bessarab@victoriametrics.com>

---------

Signed-off-by: Zakhar Bessarab <z.bessarab@victoriametrics.com>

lib/backup/fscommon/fscommon.go

@@ -52,7 +52,7 @@ func appendFilesInternal(dst []string, d *os.File) ([]string, error) {
 			// Process directory
 			dst, err = AppendFiles(dst, path)
 			if err != nil {
-				return nil, fmt.Errorf("cannot list %q: %w", path, err)
+				return nil, fmt.Errorf("cannot append files %q: %w", path, err)
 			}
 			continue
 		}
@@ -124,9 +124,6 @@ func removeEmptyDirs(dir string) (bool, error) {
 		return false, err
 	}
 	ok, err := removeEmptyDirsInternal(d)
-	if err1 := d.Close(); err1 != nil {
-		err = err1
-	}
 	if err != nil {
 		return false, err
 	}
@@ -157,7 +154,7 @@ func removeEmptyDirsInternal(d *os.File) (bool, error) {
 			// Process directory
 			ok, err := removeEmptyDirs(path)
 			if err != nil {
-				return false, fmt.Errorf("cannot list %q: %w", path, err)
+				return false, fmt.Errorf("cannot remove empty dirs %q: %w", path, err)
 			}
 			if !ok {
 				dirEntries++
@@ -221,6 +218,9 @@ func removeEmptyDirsInternal(d *os.File) (bool, error) {
 	if dirEntries > 0 {
 		return false, nil
 	}
+	if err := d.Close(); err != nil {
+		return false, fmt.Errorf("cannot close %q: %w", dir, err)
+	}
 	// Use os.RemoveAll() instead of os.Remove(), since the dir may contain special files such as flock.lock and backupnames.RestoreInProgressFilename,
 	// which must be ignored.
 	if err := os.RemoveAll(dir); err != nil {

lib/backup/fsremote/fsremote.go

@@ -68,6 +68,7 @@ func (fs *FS) ListParts() ([]common.Part, error) {
 			return nil, fmt.Errorf("cannot stat file %q for part %q: %w", file, p.Path, err)
 		}
 		p.ActualSize = uint64(fi.Size())
+		p.Path = pathToCanonical(p.Path)
 		parts = append(parts, p)
 	}
 	return parts, nil
@@ -75,6 +76,7 @@ func (fs *FS) ListParts() ([]common.Part, error) {
 
 // DeletePart deletes the given part p from fs.
 func (fs *FS) DeletePart(p common.Part) error {
+	p.Path = canonicalPathToLocal(p.Path)
 	path := fs.path(p)
 	if err := os.Remove(path); err != nil {
 		return fmt.Errorf("cannot remove %q: %w", path, err)
@@ -95,6 +97,7 @@ func (fs *FS) CopyPart(srcFS common.OriginFS, p common.Part) error {
 	if !ok {
 		return fmt.Errorf("cannot perform server-side copying from %s to %s: both of them must be fsremote", srcFS, fs)
 	}
+	p.Path = canonicalPathToLocal(p.Path)
 	srcPath := src.path(p)
 	dstPath := fs.path(p)
 	if err := fs.mkdirAll(dstPath); err != nil {
@@ -139,6 +142,7 @@ func (fs *FS) CopyPart(srcFS common.OriginFS, p common.Part) error {
 
 // DownloadPart download part p from fs to w.
 func (fs *FS) DownloadPart(p common.Part, w io.Writer) error {
+	p.Path = canonicalPathToLocal(p.Path)
 	path := fs.path(p)
 	r, err := os.Open(path)
 	if err != nil {
@@ -201,6 +205,7 @@ func (fs *FS) path(p common.Part) string {
 //
 // The function does nothing if the filePath doesn't exist.
 func (fs *FS) DeleteFile(filePath string) error {
+	filePath = canonicalPathToLocal(filePath)
 	path := filepath.Join(fs.Dir, filePath)
 	err := os.Remove(path)
 	if err != nil && !os.IsNotExist(err) {

lib/backup/fsremote/normilize_path_bsd.go

@@ -0,0 +1,12 @@
+//go:build freebsd || openbsd || dragonfly || netbsd
+// +build freebsd openbsd dragonfly netbsd
+
+package fsremote
+
+func pathToCanonical(path string) string {
+	return path
+}
+
+func canonicalPathToLocal(path string) string {
+	return path
+}

lib/backup/fsremote/normilize_path_darwin.go

@@ -0,0 +1,9 @@
+package fsremote
+
+func pathToCanonical(path string) string {
+	return path
+}
+
+func canonicalPathToLocal(path string) string {
+	return path
+}

lib/backup/fsremote/normilize_path_linux.go

@@ -0,0 +1,9 @@
+package fsremote
+
+func pathToCanonical(path string) string {
+	return path
+}
+
+func canonicalPathToLocal(path string) string {
+	return path
+}

lib/backup/fsremote/normilize_path_solaris.go

@@ -0,0 +1,9 @@
+package fsremote
+
+func pathToCanonical(path string) string {
+	return path
+}
+
+func canonicalPathToLocal(path string) string {
+	return path
+}

lib/backup/fsremote/normilize_path_windows.go

@@ -0,0 +1,11 @@
+package fsremote
+
+import "strings"
+
+func pathToCanonical(path string) string {
+	return strings.ReplaceAll(path, "\\", "/")
+}
+
+func canonicalPathToLocal(path string) string {
+	return strings.ReplaceAll(path, "/", "\\")
+}