lib/backup: prevent from restoring to directory which is in use by VictoriaMetrics during the restore

lib/backup/actions/restore.go

@@ -8,6 +8,7 @@ import (
 
 	"github.com/VictoriaMetrics/VictoriaMetrics/lib/backup/common"
 	"github.com/VictoriaMetrics/VictoriaMetrics/lib/backup/fslocal"
+	"github.com/VictoriaMetrics/VictoriaMetrics/lib/fs"
 	"github.com/VictoriaMetrics/VictoriaMetrics/lib/logger"
 )
 
@@ -34,6 +35,16 @@ type Restore struct {
 func (r *Restore) Run() error {
 	startTime := time.Now()
 
+	// Make sure VictoriaMetrics doesn't run during the restore process.
+	if err := fs.MkdirAllIfNotExist(r.Dst.Dir); err != nil {
+		return fmt.Errorf("cannot create dir %q: %s", r.Dst.Dir, err)
+	}
+	flockF, err := fs.CreateFlockFile(r.Dst.Dir)
+	if err != nil {
+		return fmt.Errorf("cannot create lock file in %q; make sure VictoriaMetrics doesn't use the dir; error: %s", r.Dst.Dir, err)
+	}
+	defer fs.MustClose(flockF)
+
 	concurrency := r.Concurrency
 	src := r.Src
 	dst := r.Dst

lib/backup/fscommon/fscommon.go

@@ -72,6 +72,11 @@ func appendFilesInternal(dst []string, d *os.File) ([]string, error) {
 		if name == "." || name == ".." {
 			continue
 		}
+		if name == "flock.lock" {
+			// Do not take into account flock.lock files, since they are used
+			// for preventing from concurrent access.
+			continue
+		}
 		path := dir + "/" + name
 		if fi.IsDir() {
 			// Process directory