fix(docker-compose, prometheus, telemetry, proxy): standardize collector naming and improve error handling

docker-compose-coolify.yml

@@ -1,5 +1,5 @@
 services:
-  collector:
+  otel-collector:
     image: otel/opentelemetry-collector:0.111.0
     command: ["--config=/etc/otelcol/config.yaml"]
     volumes:
@@ -15,14 +15,14 @@ services:
       OTEL_SERVICE_NAME: newt
       NEWT_METRICS_PROMETHEUS_ENABLED: "true"
       NEWT_METRICS_OTLP_ENABLED: "true"
-      OTEL_EXPORTER_OTLP_ENDPOINT: "collector:4317"
+      OTEL_EXPORTER_OTLP_ENDPOINT: "otel-collector:4317"
       OTEL_EXPORTER_OTLP_INSECURE: "true"
       OTEL_EXPORTER_OTLP_METRICS_TEMPORALITY_PREFERENCE: "cumulative"
       NEWT_ADMIN_ADDR: "0.0.0.0:2112"
     ports:
       - "2112:2112"
     depends_on:
-      - collector
+      - otel-collector
 
   prometheus:
     image: prom/prometheus:v2.55.0

docs/observability.md

@@ -125,7 +125,7 @@ global:
 scrape_configs:
   - job_name: otel-collector
     static_configs:
-      - targets: ["collector:8889"]
+      - targets: ["otel-collector:8889"]
 ```
 
 Reason mapping (source → reason)

examples/prometheus.yml

@@ -18,4 +18,4 @@ scrape_configs:
   # WARNING: Do not enable this together with the 'newt' job above or you will double-count.
   # - job_name: 'otel-collector'
   #   static_configs:
-  #     - targets: ['collector:8889']
+  #     - targets: ['otel-collector:8889']

internal/telemetry/metrics.go

@@ -70,11 +70,26 @@ func registerInstruments() error {
 	var err error
 	initOnce.Do(func() {
 		meter = otel.Meter("newt")
-		if e := registerSiteInstruments(); e != nil { err = e; return }
-		if e := registerTunnelInstruments(); e != nil { err = e; return }
-		if e := registerConnInstruments(); e != nil { err = e; return }
-		if e := registerConfigInstruments(); e != nil { err = e; return }
-		if e := registerBuildWSProxyInstruments(); e != nil { err = e; return }
+		if e := registerSiteInstruments(); e != nil {
+			err = e
+			return
+		}
+		if e := registerTunnelInstruments(); e != nil {
+			err = e
+			return
+		}
+		if e := registerConnInstruments(); e != nil {
+			err = e
+			return
+		}
+		if e := registerConfigInstruments(); e != nil {
+			err = e
+			return
+		}
+		if e := registerBuildWSProxyInstruments(); e != nil {
+			err = e
+			return
+		}
 	})
 	return err
 }
@@ -83,13 +98,19 @@ func registerSiteInstruments() error {
 	var err error
 	mSiteRegistrations, err = meter.Int64Counter("newt_site_registrations_total",
 		metric.WithDescription("Total site registration attempts"))
-	if err != nil { return err }
+	if err != nil {
+		return err
+	}
 	mSiteOnline, err = meter.Int64ObservableGauge("newt_site_online",
 		metric.WithDescription("Site online (0/1)"))
-	if err != nil { return err }
+	if err != nil {
+		return err
+	}
 	mSiteLastHeartbeat, err = meter.Float64ObservableGauge("newt_site_last_heartbeat_seconds",
 		metric.WithDescription("Seconds since last site heartbeat"))
-	if err != nil { return err }
+	if err != nil {
+		return err
+	}
 	return nil
 }
 
@@ -97,18 +118,26 @@ func registerTunnelInstruments() error {
 	var err error
 	mTunnelSessions, err = meter.Int64ObservableGauge("newt_tunnel_sessions",
 		metric.WithDescription("Active tunnel sessions"))
-	if err != nil { return err }
+	if err != nil {
+		return err
+	}
 	mTunnelBytes, err = meter.Int64Counter("newt_tunnel_bytes_total",
 		metric.WithDescription("Tunnel bytes ingress/egress"),
 		metric.WithUnit("By"))
-	if err != nil { return err }
+	if err != nil {
+		return err
+	}
 	mTunnelLatency, err = meter.Float64Histogram("newt_tunnel_latency_seconds",
 		metric.WithDescription("Per-tunnel latency in seconds"),
 		metric.WithUnit("s"))
-	if err != nil { return err }
+	if err != nil {
+		return err
+	}
 	mReconnects, err = meter.Int64Counter("newt_tunnel_reconnects_total",
 		metric.WithDescription("Tunnel reconnect events"))
-	if err != nil { return err }
+	if err != nil {
+		return err
+	}
 	return nil
 }
 
@@ -116,10 +145,14 @@ func registerConnInstruments() error {
 	var err error
 	mConnAttempts, err = meter.Int64Counter("newt_connection_attempts_total",
 		metric.WithDescription("Connection attempts"))
-	if err != nil { return err }
+	if err != nil {
+		return err
+	}
 	mConnErrors, err = meter.Int64Counter("newt_connection_errors_total",
 		metric.WithDescription("Connection errors by type"))
-	if err != nil { return err }
+	if err != nil {
+		return err
+	}
 	return nil
 }
 
@@ -310,10 +343,13 @@ func ObserveProxyAsyncBacklogObs(o metric.Observer, value int64, attrs []attribu
 }
 
 func IncProxyDrops(ctx context.Context, tunnelID, protocol string) {
-	mProxyDropsTotal.Add(ctx, 1, metric.WithAttributes(attrsWithSite(
-		attribute.String("tunnel_id", tunnelID),
+	attrs := []attribute.KeyValue{
 		attribute.String("protocol", protocol),
-	)...))
+	}
+	if ShouldIncludeTunnelID() && tunnelID != "" {
+		attrs = append(attrs, attribute.String("tunnel_id", tunnelID))
+	}
+	mProxyDropsTotal.Add(ctx, 1, metric.WithAttributes(attrsWithSite(attrs...)...))
 }
 
 // --- Config/PKI helpers ---

proxy/manager.go

@@ -275,7 +275,7 @@ func (pm *ProxyManager) Start() error {
 			telemetry.ObserveProxyActiveConnsObs(o, e.activeTCP.Load(), e.attrOutTCP.ToSlice())
 			telemetry.ObserveProxyActiveConnsObs(o, e.activeUDP.Load(), e.attrOutUDP.ToSlice())
 			// backlog bytes (sum of unflushed counters)
-			b := int64(e.bytesInTCP.Load()+e.bytesOutTCP.Load()+e.bytesInUDP.Load()+e.bytesOutUDP.Load())
+			b := int64(e.bytesInTCP.Load() + e.bytesOutTCP.Load() + e.bytesInUDP.Load() + e.bytesOutUDP.Load())
 			telemetry.ObserveProxyAsyncBacklogObs(o, b, e.attrOutTCP.ToSlice())
 			telemetry.ObserveProxyBufferBytesObs(o, b, e.attrOutTCP.ToSlice())
 		}
@@ -599,13 +599,14 @@ func (pm *ProxyManager) handleUDPProxy(conn *gonet.UDPConn, targetAddr string) {
 			}
 
 			targetConn, err = net.DialUDP("udp", nil, targetUDPAddr)
-				if e := pm.getEntry(pm.currentTunnelID); e != nil {
-					e.activeUDP.Add(1)
-				}
 			if err != nil {
 				logger.Error("Error connecting to target: %v", err)
 				continue
 			}
+			// Only increment activeUDP after a successful DialUDP
+			if e := pm.getEntry(pm.currentTunnelID); e != nil {
+				e.activeUDP.Add(1)
+			}
 
 			clientsMutex.Lock()
 			clientConns[clientKey] = targetConn