vpnem: VPN infrastructure with load-balanced multi-protocol nodesHEADmain

- Multi-protocol VPS nodes (VLESS-REALITY + Hysteria2 + SOCKS5)
- Smart load balancing via recommendation API
- Windows/Linux client (Go + Wails + sing-box)
- Server API with RealIP detection and connection tracking
- Auto-deployment via vpnui control plane
- Silent Windows installer with UAC elevation
- Load-based server recommendation (no sticky sessions)
- Best Server one-click connection workflow

1 files changed, 33 insertions, 0 deletions

diff --git a/internal/sync/health.go b/internal/sync/health.go
new file mode 100644
index 0000000..4d6ceca
--- /dev/null
+++ b/internal/sync/health.go
@@ -0,0 +1,33 @@
+package sync
+
+import (
+	"fmt"
+	"net"
+	"time"
+
+	"vpnem/internal/models"
+)
+
+// HealthCheck tests if a server's proxy port is reachable.
+func HealthCheck(server models.Server, timeout time.Duration) error {
+	addr := fmt.Sprintf("%s:%d", server.Server, server.ServerPort)
+	conn, err := net.DialTimeout("tcp", addr, timeout)
+	if err != nil {
+		return fmt.Errorf("server %s unreachable: %w", server.Tag, err)
+	}
+	conn.Close()
+	return nil
+}
+
+// FindHealthyServer returns the first healthy non-RU server from the list.
+func FindHealthyServer(servers []models.Server, timeout time.Duration) *models.Server {
+	for _, s := range servers {
+		if s.Region == "RU" {
+			continue
+		}
+		if err := HealthCheck(s, timeout); err == nil {
+			return &s
+		}
+	}
+	return nil
+}