avoid infinite loop WaitUntilConnected() (#3431)

https://github.com/seaweedfs/seaweedfs/issues/3421

weed/server/master_server.go

@@ -276,11 +276,9 @@ func (ms *MasterServer) startAdminScripts() {
 	go commandEnv.MasterClient.KeepConnectedToMaster()
 
 	go func() {
-		commandEnv.MasterClient.WaitUntilConnected()
-
 		for {
 			time.Sleep(time.Duration(sleepMinutes) * time.Minute)
-			if ms.Topo.IsLeader() {
+			if ms.Topo.IsLeader() && ms.MasterClient.GetMaster() != "" {
 				shellOptions.FilerAddress = ms.GetOneFiler(cluster.FilerGroupName(*shellOptions.FilerGroup))
 				if shellOptions.FilerAddress == "" {
 					continue

weed/wdclient/masterclient.go

@@ -93,7 +93,10 @@ func (mc *MasterClient) GetMasters() map[string]pb.ServerAddress {
 }
 
 func (mc *MasterClient) WaitUntilConnected() {
-	for mc.currentMaster == "" {
+	for {
+		if mc.currentMaster != "" {
+			return
+		}
 		time.Sleep(time.Duration(rand.Int31n(200)) * time.Millisecond)
 	}
 }
@@ -135,7 +138,6 @@ func (mc *MasterClient) FindLeaderFromOtherPeers(myMasterAddress pb.ServerAddres
 func (mc *MasterClient) tryAllMasters() {
 	var nextHintedLeader pb.ServerAddress
 	for _, master := range mc.masters {
-
 		nextHintedLeader = mc.tryConnectToMaster(master)
 		for nextHintedLeader != "" {
 			nextHintedLeader = mc.tryConnectToMaster(nextHintedLeader)
@@ -228,9 +230,7 @@ func (mc *MasterClient) tryConnectToMaster(master pb.ServerAddress) (nextHintedL
 					}
 				}
 			}
-
 		}
-
 	})
 	if gprcErr != nil {
 		stats.MasterClientConnectCounter.WithLabelValues(stats.Failed).Inc()