feat(cli/proxy): add OTLP timeout flag and make proxy metrics resilient

main.go

@@ -175,6 +175,7 @@ func main() {
 		otelMetricsEndpoint       string
 		otelMetricsInsecure       bool
 		otelMetricsExportInterval time.Duration
+		otelMetricsTimeout        time.Duration
 	)
 
 	interfaceName = os.Getenv("INTERFACE")
@@ -229,6 +230,14 @@ func main() {
 			log.Printf("WARN: invalid OTEL_METRICS_EXPORT_INTERVAL=%q: %v", v, err2)
 		}
 	}
+	otelMetricsTimeout = 10 * time.Second // default
+	if v := os.Getenv("OTEL_METRICS_TIMEOUT"); v != "" {
+		if d, err2 := time.ParseDuration(v); err2 == nil {
+			otelMetricsTimeout = d
+		} else {
+			log.Printf("WARN: invalid OTEL_METRICS_TIMEOUT=%q: %v", v, err2)
+		}
+	}
 
 	if interfaceName == "" {
 		flag.StringVar(&interfaceName, "interface", "wg0", "Name of the WireGuard interface")
@@ -322,6 +331,7 @@ func main() {
 	flag.StringVar(&otelMetricsEndpoint, "otel-metrics-endpoint", otelMetricsEndpoint, "OTLP collector endpoint (e.g. localhost:4317)")
 	flag.BoolVar(&otelMetricsInsecure, "otel-metrics-insecure", otelMetricsInsecure, "Disable TLS for OTLP connection")
 	flag.DurationVar(&otelMetricsExportInterval, "otel-metrics-export-interval", otelMetricsExportInterval, "Interval between OTLP metric pushes")
+	flag.DurationVar(&otelMetricsTimeout, "otel-metrics-timeout", otelMetricsTimeout, "Timeout for OTLP exporter setup")
 
 	flag.Parse()
 
@@ -347,6 +357,7 @@ func main() {
 			Endpoint:       otelMetricsEndpoint,
 			Insecure:       otelMetricsInsecure,
 			ExportInterval: otelMetricsExportInterval,
+			Timeout:        otelMetricsTimeout,
 		},
 		ServiceName:           "gerbil",
 		ServiceVersion:        "1.0.0",
@@ -543,6 +554,8 @@ func main() {
 
 	// Register metrics endpoint only for Prometheus backend.
 	// OTel backend pushes to a collector; no /metrics endpoint needed.
+	// Note: metricsPath is registered directly without httpMetricsMiddleware to prevent infinite recursion.
+	// The metricsHandler must not be wrapped by the middleware, as it would observe its own observation calls.
 	if metricsHandler != nil {
 		http.Handle(metricsPath, metricsHandler)
 		logger.Info("Metrics endpoint enabled at %s", metricsPath)
@@ -1162,10 +1175,12 @@ func removePeerInternal(publicKey string) error {
 
 	// Get current peer info before removing to clear relay connections and bandwidth limits
 	var wgIPs []string
+	allowedIPsCount := 0
 	device, err := wgClient.Device(interfaceName)
 	if err == nil {
 		for _, peer := range device.Peers {
 			if peer.PublicKey.String() == publicKey {
+				allowedIPsCount = len(peer.AllowedIPs)
 				// Extract WireGuard IPs from this peer's allowed IPs
 				for _, allowedIP := range peer.AllowedIPs {
 					wgIPs = append(wgIPs, allowedIP.IP.String())
@@ -1208,7 +1223,7 @@ func removePeerInternal(publicKey string) error {
 
 	// Record metrics
 	metrics.RecordPeersTotal(interfaceName, -1)
-	metrics.RecordAllowedIPsCount(interfaceName, publicKey, -int64(len(wgIPs)))
+	metrics.RecordAllowedIPsCount(interfaceName, publicKey, -int64(allowedIPsCount))
 
 	return nil
 }

proxy/proxy.go

@@ -548,7 +548,7 @@ func (p *SNIProxy) handleConnection(clientConn net.Conn) {
 		logger.Debug("SNI extraction failed: %v", err)
 		return
 	}
-	metrics.RecordProxyTLSHandshake(hostname, time.Since(clientHelloStart).Seconds())
+	metrics.RecordProxyTLSHandshake(time.Since(clientHelloStart).Seconds())
 
 	if hostname == "" {
 		log.Println("No SNI hostname found")
@@ -596,8 +596,8 @@ func (p *SNIProxy) handleConnection(clientConn net.Conn) {
 	defer targetConn.Close()
 
 	logger.Debug("Connected to target: %s:%d", route.TargetHost, route.TargetPort)
-	metrics.RecordActiveProxyConnection(hostname, 1)
-	defer metrics.RecordActiveProxyConnection(hostname, -1)
+	metrics.RecordActiveProxyConnection(1)
+	defer metrics.RecordActiveProxyConnection(-1)
 
 	// Send PROXY protocol header if enabled
 	if p.proxyProtocol {
@@ -655,7 +655,7 @@ func (p *SNIProxy) getRoute(hostname, clientAddr string) (*RouteRecord, error) {
 	// Check local overrides first
 	if _, isOverride := p.localOverrides[hostname]; isOverride {
 		logger.Debug("Local override matched for hostname: %s", hostname)
-		metrics.RecordProxyRouteLookup("local_override", hostname)
+		metrics.RecordProxyRouteLookup("local_override")
 		return &RouteRecord{
 			Hostname:   hostname,
 			TargetHost: p.localProxyAddr,
@@ -668,7 +668,7 @@ func (p *SNIProxy) getRoute(hostname, clientAddr string) (*RouteRecord, error) {
 	_, isLocal := p.localSNIs[hostname]
 	p.localSNIsLock.RUnlock()
 	if isLocal {
-		metrics.RecordProxyRouteLookup("local", hostname)
+		metrics.RecordProxyRouteLookup("local")
 		return &RouteRecord{
 			Hostname:   hostname,
 			TargetHost: p.localProxyAddr,
@@ -679,16 +679,16 @@ func (p *SNIProxy) getRoute(hostname, clientAddr string) (*RouteRecord, error) {
 	// Check cache first
 	if cached, found := p.cache.Get(hostname); found {
 		if cached == nil {
-			metrics.RecordProxyRouteLookup("cached_not_found", hostname)
+			metrics.RecordProxyRouteLookup("cached_not_found")
 			return nil, nil // Cached negative result
 		}
 		logger.Debug("Cache hit for hostname: %s", hostname)
-		metrics.RecordProxyRouteLookup("cache_hit", hostname)
+		metrics.RecordProxyRouteLookup("cache_hit")
 		return cached.(*RouteRecord), nil
 	}
 
 	logger.Debug("Cache miss for hostname: %s, querying API", hostname)
-	metrics.RecordProxyRouteLookup("cache_miss", hostname)
+	metrics.RecordProxyRouteLookup("cache_miss")
 
 	// Query API with timeout
 	ctx, cancel := context.WithTimeout(p.ctx, 5*time.Second)
@@ -822,7 +822,7 @@ func (p *SNIProxy) pipe(hostname string, clientConn, targetConn net.Conn, client
 		}()
 
 		bytesCopied, err := io.CopyBuffer(targetConn, clientReader, *bufPtr)
-		metrics.RecordProxyBytesTransmitted(hostname, "client_to_target", bytesCopied)
+		metrics.RecordProxyBytesTransmitted("client_to_target", bytesCopied)
 		if err != nil && err != io.EOF {
 			logger.Debug("Copy client->target error: %v", err)
 		}
@@ -842,7 +842,7 @@ func (p *SNIProxy) pipe(hostname string, clientConn, targetConn net.Conn, client
 		}()
 
 		bytesCopied, err := io.CopyBuffer(clientConn, targetConn, *bufPtr)
-		metrics.RecordProxyBytesTransmitted(hostname, "target_to_client", bytesCopied)
+		metrics.RecordProxyBytesTransmitted("target_to_client", bytesCopied)
 		if err != nil && err != io.EOF {
 			logger.Debug("Copy target->client error: %v", err)
 		}