accounts/keystore: replace inotify with fsnotify (#26176)

accounts/keystore/watch.go

@@ -23,7 +23,7 @@ import (
 	"time"
 
 	"github.com/ethereum/go-ethereum/log"
-	"github.com/rjeczalik/notify"
+	"github.com/fsnotify/fsnotify"
 )
 
 type watcher struct {
@@ -31,14 +31,12 @@ type watcher struct {
 	running  bool // set to true when runloop begins
 	runEnded bool // set to true when runloop ends
 	starting bool // set to true prior to runloop starting
-	ev       chan notify.EventInfo
 	quit     chan struct{}
 }
 
 func newWatcher(ac *accountCache) *watcher {
 	return &watcher{
 		ac:   ac,
-		ev:   make(chan notify.EventInfo, 10),
 		quit: make(chan struct{}),
 	}
 }
@@ -71,12 +69,19 @@ func (w *watcher) loop() {
 	}()
 	logger := log.New("path", w.ac.keydir)
 
-	if err := notify.Watch(w.ac.keydir, w.ev, notify.All); err != nil {
-		logger.Trace("Failed to watch keystore folder", "err", err)
+	// Create new watcher.
+	watcher, err := fsnotify.NewWatcher()
+	if err != nil {
+		log.Error("Failed to start filesystem watcher", "err", err)
 		return
 	}
-	defer notify.Stop(w.ev)
-	logger.Trace("Started watching keystore folder")
+	defer watcher.Close()
+	if err := watcher.Add(w.ac.keydir); err != nil {
+		logger.Warn("Failed to watch keystore folder", "err", err)
+		return
+	}
+
+	logger.Trace("Started watching keystore folder", "folder", w.ac.keydir)
 	defer logger.Trace("Stopped watching keystore folder")
 
 	w.ac.mu.Lock()
@@ -100,12 +105,24 @@ func (w *watcher) loop() {
 		select {
 		case <-w.quit:
 			return
-		case <-w.ev:
+		case _, ok := <-watcher.Events:
+			if !ok {
+				return
+			}
 			// Trigger the scan (with delay), if not already triggered
 			if !rescanTriggered {
 				debounce.Reset(debounceDuration)
 				rescanTriggered = true
 			}
+			// The fsnotify library does provide more granular event-info, it
+			// would be possible to refresh individual affected files instead
+			// of scheduling a full rescan. For most cases though, the
+			// full rescan is quick and obviously simplest.
+		case err, ok := <-watcher.Errors:
+			if !ok {
+				return
+			}
+			log.Info("Filsystem watcher error", "err", err)
 		case <-debounce.C:
 			w.ac.scanAccounts()
 			rescanTriggered = false