added a stop request guard in starting a control channel

client.go

@@ -1075,6 +1075,10 @@ func (c *Client) AddNewClientConn(cfg *ClientConfig) (*ClientConn, error) {
 	var ok bool
 	var id uint32
 
+	if len(cfg.ServerAddrs) <= 0 {
+		return nil, fmt.Errorf("no server rpc address specified")
+	}
+
 	cts = NewClientConn(c, cfg)
 
 	c.cts_mtx.Lock()
@@ -1264,20 +1268,38 @@ func (c *Client) RunCtlTask(wg *sync.WaitGroup) {
 			// by creating the listener explicitly.
 			//   err = cs.ListenAndServe()
 			//   err = cs.ListenAndServeTLS("", "") // c.tlscfg must provide a certificate and a key
-			l, err = net.Listen(tcp_addr_str_class(cs.Addr), cs.Addr)
-			if err == nil {
-				if c.ctltlscfg == nil {
-					err = cs.Serve(l)
-				} else {
-					err = cs.ServeTLS(l, "", "") // c.ctltlscfg must provide a certificate and a key
+
+			//cs.shuttingDown(), as the name indicates, is not expoosed by the net/http
+			//so I have to use my own indicator to check if it's been shutdown..
+			//
+			if c.stop_req.Load() == false {
+				// this guard has a flaw in that the stop request can be made
+				// between the check above and net.Listen() below.
+				l, err = net.Listen(tcp_addr_str_class(cs.Addr), cs.Addr)
+				if err == nil {
+					if c.stop_req.Load() == false {
+						// check it again to make the guard slightly more stable
+						// although it's still possible that the stop request is made
+						// after Listen()
+						if c.ctltlscfg == nil {
+							err = cs.Serve(l)
+						} else {
+							err = cs.ServeTLS(l, "", "") // c.ctltlscfg must provide a certificate and a key
+						}
+					} else {
+						err = fmt.Errorf("stop requested")
+					}
+					l.Close()
 				}
-				l.Close()
+			} else {
+				err = fmt.Errorf("stop requested")
 			}
 			if errors.Is(err, http.ErrServerClosed) {
 				c.log.Write("", LOG_INFO, "Control channel[%d] ended", i)
 			} else {
 				c.log.Write("", LOG_ERROR, "Control channel[%d] error - %s", i, err.Error())
 			}
+
 			l_wg.Done()
 		}(idx, ctl)
 	}
@@ -1295,17 +1317,9 @@ func (c *Client) RunTask(wg *sync.WaitGroup) {
 	// so no call to wg.Done()
 }
 
-func (c *Client) start_service(data interface{}) (*ClientConn, error) {
+func (c *Client) start_service(cfg *ClientConfig) (*ClientConn, error) {
 	var cts *ClientConn
 	var err error
-	var cfg *ClientConfig
-	var ok bool
-
-	cfg, ok = data.(*ClientConfig)
-	if !ok {
-		err = fmt.Errorf("invalid configuration given")
-		return nil, err
-	}
 
 	cts, err = c.AddNewClientConn(cfg)
 	if err != nil {
@@ -1320,14 +1334,24 @@ func (c *Client) start_service(data interface{}) (*ClientConn, error) {
 }
 
 func (c *Client) StartService(data interface{}) {
-	var cts *ClientConn
-	var err error
+	var cfg *ClientConfig
+	var ok bool
 
-	cts, err = c.start_service(data)
-	if err != nil {
-		c.log.Write("", LOG_ERROR, "Failed to start service - %s", err.Error())
+	cfg, ok = data.(*ClientConfig)
+	if !ok {
+		c.log.Write("", LOG_ERROR, "Failed to start service - invalid configuration - %v", data)
 	} else {
-		c.log.Write("", LOG_INFO, "Started service for %v [%d]", cts.cfg.ServerAddrs, cts.cfg.Id)
+		var cts *ClientConn
+		var err error
+
+		if len(cfg.ServerAddrs) > 0 {
+			cts, err = c.start_service(cfg)
+			if err != nil {
+				c.log.Write("", LOG_ERROR, "Failed to start service - %s", err.Error())
+			} else {
+				c.log.Write("", LOG_INFO, "Started service for %v [%d]", cts.cfg.ServerAddrs, cts.cfg.Id)
+			}
+		}
 	}
 }
 

cmd/main.go

@@ -234,14 +234,11 @@ func client_main(ctl_addrs []string, rpc_addrs []string, peer_addrs []string, cf
 		log_mask = log_strings_to_mask(cfg.APP.LogMask)
 	}
 
-	if len(rpc_addrs) <= 0 {
-		return fmt.Errorf("no rpc server address specified")
-	}
-
+	// unlke the server, we allow the client to start with no rpc address.
+	// no check if len(rpc_addrs) <= 0 is mdde here.
 	cc.ServerAddrs = rpc_addrs
 	cc.PeerAddrs = peer_addrs
 
-	// TODO: Change out field depending on cfg.APP.LogFile
 	logger = &AppLogger{id: "client", out: os.Stderr, mask: log_mask}
 	c = hodu.NewClient(
 		context.Background(),

server.go

@@ -1020,17 +1020,26 @@ func (s *Server) RunCtlTask(wg *sync.WaitGroup) {
 
 			s.log.Write("", LOG_INFO, "Control channel[%d] started on %s", i, s.ctl_addr[i])
 
-			// defeat hard-coded "tcp" in ListenAndServe() and ListenAndServeTLS()
-			//  err = cs.ListenAndServe()
-			//  err = cs.ListenAndServeTLS("", "")
-			l, err = net.Listen(tcp_addr_str_class(cs.Addr), cs.Addr)
-			if err == nil {
-				if s.ctltlscfg == nil {
-					err = cs.Serve(l)
-				} else {
-					err = cs.ServeTLS(l, "", "") // s.ctltlscfg must provide a certificate and a key
+
+			if s.stop_req.Load() == false {
+				// defeat hard-coded "tcp" in ListenAndServe() and ListenAndServeTLS()
+				//  err = cs.ListenAndServe()
+				//  err = cs.ListenAndServeTLS("", "")
+				l, err = net.Listen(tcp_addr_str_class(cs.Addr), cs.Addr)
+				if err == nil {
+					if s.stop_req.Load() == false {
+						if s.ctltlscfg == nil {
+							err = cs.Serve(l)
+						} else {
+							err = cs.ServeTLS(l, "", "") // s.ctltlscfg must provide a certificate and a key
+						}
+					} else {
+						err = fmt.Errorf("stop requested")
+					}
+					l.Close()
 				}
-				l.Close()
+			} else {
+				err = fmt.Errorf("stop requested")
 			}
 			if errors.Is(err, http.ErrServerClosed) {
 				s.log.Write("", LOG_INFO, "Control channel[%d] ended", i)