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, 62 insertions, 0 deletions

diff --git a/internal/engine/logger.go b/internal/engine/logger.go
new file mode 100644
index 0000000..c448a56
--- /dev/null
+++ b/internal/engine/logger.go
@@ -0,0 +1,62 @@
+package engine
+
+import (
+	"os"
+	"path/filepath"
+	"sync"
+)
+
+// RingLog keeps last N log lines in memory and optionally writes to file.
+type RingLog struct {
+	mu    sync.Mutex
+	lines []string
+	max   int
+	file  *os.File
+}
+
+// NewRingLog creates a ring buffer logger.
+func NewRingLog(maxLines int, dataDir string) *RingLog {
+	rl := &RingLog{
+		lines: make([]string, 0, maxLines),
+		max:   maxLines,
+	}
+	if dataDir != "" {
+		f, err := os.OpenFile(filepath.Join(dataDir, "vpnem.log"),
+			os.O_CREATE|os.O_WRONLY|os.O_APPEND, 0o644)
+		if err == nil {
+			rl.file = f
+		}
+	}
+	return rl
+}
+
+// Add appends a line.
+func (rl *RingLog) Add(line string) {
+	rl.mu.Lock()
+	defer rl.mu.Unlock()
+
+	if len(rl.lines) >= rl.max {
+		rl.lines = rl.lines[1:]
+	}
+	rl.lines = append(rl.lines, line)
+
+	if rl.file != nil {
+		rl.file.WriteString(line + "\n")
+	}
+}
+
+// Lines returns all current lines.
+func (rl *RingLog) Lines() []string {
+	rl.mu.Lock()
+	defer rl.mu.Unlock()
+	cp := make([]string, len(rl.lines))
+	copy(cp, rl.lines)
+	return cp
+}
+
+// Close closes the log file.
+func (rl *RingLog) Close() {
+	if rl.file != nil {
+		rl.file.Close()
+	}
+}