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

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 ---