Add metric for RTT of WebSocket ping messages.

client.go

@@ -353,6 +353,7 @@ func (c *Client) ReadPump() {
 					log.Printf("Client from %s has RTT of %d ms (%s)", addr, rtt_ms, rtt)
 				}
 			}
+			statsClientRTT.Observe(float64(rtt.Milliseconds()))
 			c.getHandler().OnRTTReceived(c, rtt)
 		}
 		return nil

client_stats_prometheus.go

@@ -32,9 +32,17 @@ var (
 		Name:      "countries_total",
 		Help:      "The total number of connections by country",
 	}, []string{"country"})
+	statsClientRTT = prometheus.NewHistogram(prometheus.HistogramOpts{
+		Namespace: "signaling",
+		Subsystem: "client",
+		Name:      "rtt",
+		Help:      "The roundtrip time of WebSocket ping messages in milliseconds",
+		Buckets:   prometheus.ExponentialBucketsRange(1, 30000, 50),
+	})
 
 	clientStats = []prometheus.Collector{
 		statsClientCountries,
+		statsClientRTT,
 	}
 )
 

docs/prometheus-metrics.md

@@ -59,3 +59,4 @@ The following metrics are available:
 | `signaling_mcu_backend_usage`                     | Gauge     | 2.0.5     | The current usage of signaling proxy backends in percent                  | `url`, `direction`                |
 | `signaling_mcu_backend_bandwidth`                 | Gauge     | 2.0.5     | The current bandwidth of signaling proxy backends in bytes per second     | `url`, `direction`                |
 | `signaling_proxy_load`                            | Gauge     | 2.0.5     | The current load of the signaling proxy                                   |                                   |
+| `signaling_client_rtt`                            | Histogram | 2.0.5     | The roundtrip time of WebSocket ping messages in milliseconds             |                                   |