fixed address resolution

api/gateway/tron/internal/service/gateway/tronclient/client.go

@@ -52,7 +52,11 @@ func NewClient(grpcURL string, timeout time.Duration, authToken string, forceIPv
 
 	opts := []grpc.DialOption{transportCreds}
 	if forceIPv4 {
-		opts = append(opts, grpc.WithContextDialer(grpcForceIPv4Dialer))
+		host, port, err := net.SplitHostPort(address)
+		if err != nil {
+			return nil, merrors.InvalidArgument("tronclient: invalid grpc address: " + address)
+		}
+		opts = append(opts, grpc.WithContextDialer(newForceIPv4Dialer(host, port)))
 	}
 	if token := strings.TrimSpace(authToken); token != "" {
 		opts = append(opts,
@@ -71,37 +75,34 @@ func NewClient(grpcURL string, timeout time.Duration, authToken string, forceIPv
 	}, nil
 }
 
-func grpcForceIPv4Dialer(ctx context.Context, address string) (net.Conn, error) {
+func newForceIPv4Dialer(host, port string) func(context.Context, string) (net.Conn, error) {
-	host, port, err := net.SplitHostPort(address)
+	return func(ctx context.Context, _ string) (net.Conn, error) {
-	if err != nil {
+		ips, err := net.DefaultResolver.LookupIP(ctx, "ip4", host)
-		return nil, err
+		if err != nil {
-	}
+			return nil, err
-
-	ips, err := net.DefaultResolver.LookupIP(ctx, "ip4", host)
-	if err != nil {
-		return nil, err
-	}
-	if len(ips) == 0 {
-		return nil, merrors.Internal(fmt.Sprintf("no IPv4 address found for %s", host))
-	}
-
-	var dialer net.Dialer
-	var lastErr error
-	for _, ip := range ips {
-		target := net.JoinHostPort(ip.String(), port)
-		conn, err := dialer.DialContext(ctx, "tcp4", target)
-		if err == nil {
-			return conn, nil
 		}
-		lastErr = err
+		if len(ips) == 0 {
-		if ctx.Err() != nil {
+			return nil, merrors.Internal(fmt.Sprintf("no IPv4 address found for %s", host))
-			break
 		}
+
+		var dialer net.Dialer
+		var lastErr error
+		for _, ip := range ips {
+			target := net.JoinHostPort(ip.String(), port)
+			conn, err := dialer.DialContext(ctx, "tcp4", target)
+			if err == nil {
+				return conn, nil
+			}
+			lastErr = err
+			if ctx.Err() != nil {
+				break
+			}
+		}
+		if lastErr != nil {
+			return nil, merrors.Internal(fmt.Sprintf("failed to dial any IPv4 address for %s: %v", host, lastErr))
+		}
+		return nil, merrors.Internal(fmt.Sprintf("failed to dial IPv4 address for %s", host))
 	}
-	if lastErr != nil {
-		return nil, merrors.Internal(fmt.Sprintf("failed to dial any IPv4 address for %s: %v", host, lastErr))
-	}
-	return nil, merrors.Internal(fmt.Sprintf("failed to dial IPv4 address for %s", host))
 }
 
 func normalizeGRPCAddress(grpcURL string) (string, bool, error) {