From 8526c2da257e8b5e9bf1c640f66fd93daab2fe1f Mon Sep 17 00:00:00 2001
From: constansino <louishino0524@gmail.com>
Date: Thu, 5 Mar 2026 19:12:57 +0800
Subject: [PATCH 1/2] fix(watcher): debounce auth event callback storms

---
 internal/watcher/clients.go | 62 +++++++++++++++++++++++++++++++++++--
 internal/watcher/watcher.go |  6 ++++
 2 files changed, 66 insertions(+), 2 deletions(-)

diff --git a/internal/watcher/clients.go b/internal/watcher/clients.go
index cf0ed076..a1f00f14 100644
--- a/internal/watcher/clients.go
+++ b/internal/watcher/clients.go
@@ -183,7 +183,7 @@ func (w *Watcher) addOrUpdateClient(path string) {
 
 	if w.reloadCallback != nil {
 		log.Debugf("triggering server update callback after add/update")
-		w.reloadCallback(cfg)
+		w.triggerServerUpdate(cfg)
 	}
 	w.persistAuthAsync(fmt.Sprintf("Sync auth %s", filepath.Base(path)), path)
 }
@@ -202,7 +202,7 @@ func (w *Watcher) removeClient(path string) {
 
 	if w.reloadCallback != nil {
 		log.Debugf("triggering server update callback after removal")
-		w.reloadCallback(cfg)
+		w.triggerServerUpdate(cfg)
 	}
 	w.persistAuthAsync(fmt.Sprintf("Remove auth %s", filepath.Base(path)), path)
 }
@@ -303,3 +303,61 @@ func (w *Watcher) persistAuthAsync(message string, paths ...string) {
 		}
 	}()
 }
+
+func (w *Watcher) stopServerUpdateTimer() {
+	w.serverUpdateMu.Lock()
+	defer w.serverUpdateMu.Unlock()
+	if w.serverUpdateTimer != nil {
+		w.serverUpdateTimer.Stop()
+		w.serverUpdateTimer = nil
+	}
+	w.serverUpdatePend = false
+}
+
+func (w *Watcher) triggerServerUpdate(cfg *config.Config) {
+	if w == nil || w.reloadCallback == nil || cfg == nil {
+		return
+	}
+
+	now := time.Now()
+
+	w.serverUpdateMu.Lock()
+	if w.serverUpdateLast.IsZero() || now.Sub(w.serverUpdateLast) >= serverUpdateDebounce {
+		w.serverUpdateLast = now
+		w.serverUpdateMu.Unlock()
+		w.reloadCallback(cfg)
+		return
+	}
+
+	if w.serverUpdatePend {
+		w.serverUpdateMu.Unlock()
+		return
+	}
+
+	delay := serverUpdateDebounce - now.Sub(w.serverUpdateLast)
+	if delay < 10*time.Millisecond {
+		delay = 10 * time.Millisecond
+	}
+	w.serverUpdatePend = true
+	if w.serverUpdateTimer != nil {
+		w.serverUpdateTimer.Stop()
+	}
+	w.serverUpdateTimer = time.AfterFunc(delay, func() {
+		w.clientsMutex.RLock()
+		latestCfg := w.config
+		w.clientsMutex.RUnlock()
+		if latestCfg == nil || w.reloadCallback == nil {
+			w.serverUpdateMu.Lock()
+			w.serverUpdatePend = false
+			w.serverUpdateMu.Unlock()
+			return
+		}
+
+		w.serverUpdateMu.Lock()
+		w.serverUpdateLast = time.Now()
+		w.serverUpdatePend = false
+		w.serverUpdateMu.Unlock()
+		w.reloadCallback(latestCfg)
+	})
+	w.serverUpdateMu.Unlock()
+}
diff --git a/internal/watcher/watcher.go b/internal/watcher/watcher.go
index 9f370127..c40fef7b 100644
--- a/internal/watcher/watcher.go
+++ b/internal/watcher/watcher.go
@@ -35,6 +35,10 @@ type Watcher struct {
 	clientsMutex      sync.RWMutex
 	configReloadMu    sync.Mutex
 	configReloadTimer *time.Timer
+	serverUpdateMu    sync.Mutex
+	serverUpdateTimer *time.Timer
+	serverUpdateLast  time.Time
+	serverUpdatePend  bool
 	reloadCallback    func(*config.Config)
 	watcher           *fsnotify.Watcher
 	lastAuthHashes    map[string]string
@@ -76,6 +80,7 @@ const (
 	replaceCheckDelay        = 50 * time.Millisecond
 	configReloadDebounce     = 150 * time.Millisecond
 	authRemoveDebounceWindow = 1 * time.Second
+	serverUpdateDebounce     = 1 * time.Second
 )
 
 // NewWatcher creates a new file watcher instance
@@ -116,6 +121,7 @@ func (w *Watcher) Start(ctx context.Context) error {
 func (w *Watcher) Stop() error {
 	w.stopDispatch()
 	w.stopConfigReloadTimer()
+	w.stopServerUpdateTimer()
 	return w.watcher.Close()
 }
 

From ac95e92829ae945c9005fb899e1567c4f83b0344 Mon Sep 17 00:00:00 2001
From: constansino <louishino0524@gmail.com>
Date: Thu, 5 Mar 2026 19:25:57 +0800
Subject: [PATCH 2/2] fix(watcher): guard debounced callback after Stop

---
 internal/watcher/clients.go | 8 +++++++-
 internal/watcher/watcher.go | 3 +++
 2 files changed, 10 insertions(+), 1 deletion(-)

diff --git a/internal/watcher/clients.go b/internal/watcher/clients.go
index a1f00f14..de1b80f4 100644
--- a/internal/watcher/clients.go
+++ b/internal/watcher/clients.go
@@ -318,6 +318,9 @@ func (w *Watcher) triggerServerUpdate(cfg *config.Config) {
 	if w == nil || w.reloadCallback == nil || cfg == nil {
 		return
 	}
+	if w.stopped.Load() {
+		return
+	}
 
 	now := time.Now()
 
@@ -343,10 +346,13 @@ func (w *Watcher) triggerServerUpdate(cfg *config.Config) {
 		w.serverUpdateTimer.Stop()
 	}
 	w.serverUpdateTimer = time.AfterFunc(delay, func() {
+		if w.stopped.Load() {
+			return
+		}
 		w.clientsMutex.RLock()
 		latestCfg := w.config
 		w.clientsMutex.RUnlock()
-		if latestCfg == nil || w.reloadCallback == nil {
+		if latestCfg == nil || w.reloadCallback == nil || w.stopped.Load() {
 			w.serverUpdateMu.Lock()
 			w.serverUpdatePend = false
 			w.serverUpdateMu.Unlock()
diff --git a/internal/watcher/watcher.go b/internal/watcher/watcher.go
index c40fef7b..76e2dee5 100644
--- a/internal/watcher/watcher.go
+++ b/internal/watcher/watcher.go
@@ -6,6 +6,7 @@ import (
 	"context"
 	"strings"
 	"sync"
+	"sync/atomic"
 	"time"
 
 	"github.com/fsnotify/fsnotify"
@@ -39,6 +40,7 @@ type Watcher struct {
 	serverUpdateTimer *time.Timer
 	serverUpdateLast  time.Time
 	serverUpdatePend  bool
+	stopped           atomic.Bool
 	reloadCallback    func(*config.Config)
 	watcher           *fsnotify.Watcher
 	lastAuthHashes    map[string]string
@@ -119,6 +121,7 @@ func (w *Watcher) Start(ctx context.Context) error {
 
 // Stop stops the file watcher
 func (w *Watcher) Stop() error {
+	w.stopped.Store(true)
 	w.stopDispatch()
 	w.stopConfigReloadTimer()
 	w.stopServerUpdateTimer()