TCP connection is established only if a CONN packet can be built

eclipse-paho · Oct 10, 2024 · b7d62b9 · b7d62b9
1 parent 88e86ee
commit b7d62b9
Showing 1 changed file with 33 additions and 34 deletions.
diff --git a/autopaho/net.go b/autopaho/net.go
@@ -42,7 +42,6 @@ import (
 // context is cancelled (in which case nil will be returned).
 func establishServerConnection(ctx context.Context, cfg ClientConfig, firstConnection bool) (*paho.Client, *paho.Connack) {
 	// Note: We do not touch b.cli in order to avoid adding thread safety issues.
-	var err error
 
 	var attempt int = 0
 	for {
@@ -53,51 +52,51 @@ func establishServerConnection(ctx context.Context, cfg ClientConfig, firstConne
 			return nil, nil
 		}
 		for _, u := range cfg.ServerUrls {
-			connectionCtx, cancelConnCtx := context.WithTimeout(ctx, cfg.ConnectTimeout)
-
-			if cfg.AttemptConnection != nil { // Use custom function if it is provided
-				cfg.Conn, err = cfg.AttemptConnection(ctx, cfg, u)
-			} else {
-				switch strings.ToLower(u.Scheme) {
-				case "mqtt", "tcp", "":
-					cfg.Conn, err = attemptTCPConnection(connectionCtx, u.Host)
-				case "ssl", "tls", "mqtts", "mqtt+ssl", "tcps":
-					cfg.Conn, err = attemptTLSConnection(connectionCtx, cfg.TlsCfg, u.Host)
-				case "ws":
-					cfg.Conn, err = attemptWebsocketConnection(connectionCtx, nil, cfg.WebSocketCfg, u)
-				case "wss":
-					cfg.Conn, err = attemptWebsocketConnection(connectionCtx, cfg.TlsCfg, cfg.WebSocketCfg, u)
-				default:
-					if cfg.OnConnectError != nil {
-						cfg.OnConnectError(fmt.Errorf("unsupported scheme (%s) user in url %s", u.Scheme, u.String()))
-					}
-					cancelConnCtx()
-					continue
-				}
-			}
-
 			var connack *paho.Connack
-			if err == nil {
-				cli := paho.NewClient(cfg.ClientConfig)
-				if cfg.PahoDebug != nil {
-					cli.SetDebugLogger(cfg.PahoDebug)
-				}
 
-				if cfg.PahoErrors != nil {
-					cli.SetErrorLogger(cfg.PahoErrors)
+			cp, err := cfg.buildConnectPacket(firstConnection, u)
+			if err == nil {
+				connectionCtx, cancelConnCtx := context.WithTimeout(ctx, cfg.ConnectTimeout)
+
+				if cfg.AttemptConnection != nil { // Use custom function if it is provided
+					cfg.Conn, err = cfg.AttemptConnection(ctx, cfg, u)
+				} else {
+					switch strings.ToLower(u.Scheme) {
+					case "mqtt", "tcp", "":
+						cfg.Conn, err = attemptTCPConnection(connectionCtx, u.Host)
+					case "ssl", "tls", "mqtts", "mqtt+ssl", "tcps":
+						cfg.Conn, err = attemptTLSConnection(connectionCtx, cfg.TlsCfg, u.Host)
+					case "ws":
+						cfg.Conn, err = attemptWebsocketConnection(connectionCtx, nil, cfg.WebSocketCfg, u)
+					case "wss":
+						cfg.Conn, err = attemptWebsocketConnection(connectionCtx, cfg.TlsCfg, cfg.WebSocketCfg, u)
+					default:
+						if cfg.OnConnectError != nil {
+							cfg.OnConnectError(fmt.Errorf("unsupported scheme (%s) user in url %s", u.Scheme, u.String()))
+						}
+						cancelConnCtx()
+						continue
+					}
 				}
 
-				var cp *paho.Connect
-				cp, err = cfg.buildConnectPacket(firstConnection, u)
 				if err == nil {
+					cli := paho.NewClient(cfg.ClientConfig)
+					if cfg.PahoDebug != nil {
+						cli.SetDebugLogger(cfg.PahoDebug)
+					}
+
+					if cfg.PahoErrors != nil {
+						cli.SetErrorLogger(cfg.PahoErrors)
+					}
+
 					connack, err = cli.Connect(connectionCtx, cp) // will return an error if the connection is unsuccessful (checks the reason code)
 					if err == nil {                               // Successfully connected
 						cancelConnCtx()
 						return cli, connack
 					}
 				}
+				cancelConnCtx()
 			}
-			cancelConnCtx()
 
 			// Possible failure was due to outer context being cancelled
 			if ctx.Err() != nil {