added directory cleanup

pkg/fs/dir.go

@@ -8,6 +8,8 @@ import (
 	"os"
 	"sync"
 	"time"
+
+	"github.com/go-logr/logr"
 )
 
 var NoCacheEntry = errors.New("no cache entry")
@@ -42,8 +44,9 @@ func (dc *DirCache) Set(name string, dce *DirCacheEntry) {
 }
 
 type Dir struct {
-	f  *os.File
-	dc *DirCache
+	log logr.Logger
+	f   *os.File
+	dc  *DirCache
 }
 
 func (f *Dir) Read(_ []byte) (int, error) {
@@ -54,6 +57,19 @@ func (f *Dir) Seek(_ int64, _ int) (int64, error) {
 	return 0, io.EOF
 }
 
+func readDir(f *os.File) (fi []os.FileInfo, err error) {
+	ent, err := f.ReadDir(0)
+	if err != nil {
+		return
+	}
+	fi = make([]os.FileInfo, len(ent))
+	for j, e := range ent {
+		i, _ := e.Info()
+		fi[j] = i
+	}
+	return
+}
+
 func (f *Dir) Readdir(_ int) (fi []os.FileInfo, err error) {
 	i, err := f.Stat()
 	if err != nil {
@@ -61,13 +77,17 @@ func (f *Dir) Readdir(_ int) (fi []os.FileInfo, err error) {
 	}
 	name := f.f.Name()
 	dce, err := f.dc.Get(name)
+	log := f.log
 	if err == NoCacheEntry || i.ModTime().After(dce.mtime) {
-		fi, err = f.f.Readdir(0)
+		log.V(3).Info("cache miss")
+		fi, err = readDir(f.f)
 		if err != nil {
 			return
 		}
 		dce = &DirCacheEntry{i.ModTime(), fi}
 		f.dc.Set(name, dce)
+	} else {
+		log.V(3).Info("cache hit")
 	}
 	fi = dce.fi
 	return

pkg/fs/fs.go

@@ -205,7 +205,7 @@ func (fs *FS) Open(name string) (f http.File, err error) {
 			offline = true
 			log.V(2).Info("dir offline mode", "path", dp)
 		}
-		f = &Dir{f: sf, dc: fs.dc}
+		f = &Dir{log: log.WithName("dir"), f: sf, dc: fs.dc}
 		return
 	}
 	md := fs.metadata(name, sfi.Size())
@@ -295,10 +295,32 @@ func (fs *FS) flusher(ctx context.Context) {
 			return
 		case <-time.After(time.Minute * 5):
 		}
+		fs.cleanupEmptyDirs()
 		fs.flushMetadata()
 	}
 }
 
+func (fs *FS) cleanupEmptyDirs() {
+	filepath.WalkDir(fs.dst, func(path string, d stdfs.DirEntry, err error) error {
+		if err == nil && d.IsDir() {
+			if path == fs.dst {
+				return nil
+			}
+			empty, err := dirEmpty(path)
+			if err != nil || !empty {
+				return nil
+			}
+			log := fs.log.WithValues("dir", path)
+			log.V(2).Info("removing empty dir")
+			err = os.Remove(path)
+			if err != nil {
+				log.Error(err, "failed to remove empty dir")
+			}
+		}
+		return nil
+	})
+}
+
 func (fs *FS) flushMetadata() {
 	log := fs.log
 	fs.mu.Lock()
@@ -341,10 +363,11 @@ func dirEmpty(name string) (bool, error) {
 	if err != nil {
 		return false, err
 	}
-	defer f.Close()
-	_, err = f.Readdir(1)
+	_, err = f.ReadDir(1)
 	if err == io.EOF {
+		f.Close()
 		return true, nil
 	}
+	f.Close()
 	return false, err
 }