tls: wait for keeping storage clean to finish when stopping

modules/caddytls/tls.go

@@ -130,6 +130,7 @@ type TLS struct {
 	ctx                  caddy.Context
 	storageCleanTicker   *time.Ticker
 	storageCleanStop     chan struct{}
+	storageCleanStopDone chan struct{}
 	logger               *zap.Logger
 	events               *caddyevents.App
 
@@ -439,6 +440,9 @@ func (t *TLS) Stop() error {
 	if t.storageCleanTicker != nil {
 		t.storageCleanTicker.Stop()
 	}
+	if t.storageCleanStopDone != nil {
+		<-t.storageCleanStopDone
+	}
 	return nil
 }
 
@@ -788,16 +792,20 @@ func (t *TLS) HasCertificateForSubject(subject string) bool {
 func (t *TLS) keepStorageClean() {
 	t.storageCleanTicker = time.NewTicker(t.storageCleanInterval())
 	t.storageCleanStop = make(chan struct{})
+	t.storageCleanStopDone = make(chan struct{})
 	go func() {
 		defer func() {
 			if err := recover(); err != nil {
 				log.Printf("[PANIC] storage cleaner: %v\n%s", err, debug.Stack())
+				// close the channel manually if panicked
+				close(t.storageCleanStopDone)
 			}
 		}()
 		t.cleanStorageUnits()
 		for {
 			select {
 			case <-t.storageCleanStop:
+				close(t.storageCleanStopDone)
 				return
 			case <-t.storageCleanTicker.C:
 				t.cleanStorageUnits()