Add option to emit metrics and logs when players connect to the router (#391)

cmd/mc-router/main.go

@@ -54,6 +54,7 @@ type Config struct {
 	UseProxyProtocol      bool              `default:"false" usage:"Send PROXY protocol to backend servers"`
 	ReceiveProxyProtocol  bool              `default:"false" usage:"Receive PROXY protocol from backend servers, by default trusts every proxy header that it receives, combine with -trusted-proxies to specify a list of trusted proxies"`
 	TrustedProxies        []string          `usage:"Comma delimited list of CIDR notation IP blocks to trust when receiving PROXY protocol"`
+	RecordLogins          bool              `default:"false" usage:"Log and generate metrics on player logins. Metrics only supported with influxdb or prometheus backend"`
 	MetricsBackendConfig  MetricsBackendConfig
 	RoutesConfig          string `usage:"Name or full path to routes config file"`
 	NgrokToken            string `usage:"If set, an ngrok tunnel will be established. It is HIGHLY recommended to pass as an environment variable."`
@@ -142,7 +143,7 @@ func main() {
 		trustedIpNets = append(trustedIpNets, ipNet)
 	}
 
-	connector := server.NewConnector(metricsBuilder.BuildConnectorMetrics(), config.UseProxyProtocol, config.ReceiveProxyProtocol, trustedIpNets)
+	connector := server.NewConnector(metricsBuilder.BuildConnectorMetrics(), config.UseProxyProtocol, config.ReceiveProxyProtocol, trustedIpNets, config.RecordLogins)
 
 	clientFilter, err := server.NewClientFilter(config.ClientsToAllow, config.ClientsToDeny)
 	if err != nil {

cmd/mc-router/metrics.go

@@ -65,6 +65,8 @@ func (b expvarMetricsBuilder) BuildConnectorMetrics() *server.ConnectorMetrics {
 		ConnectionsFrontend: c,
 		ConnectionsBackend:  c,
 		ActiveConnections:   expvarMetrics.NewGauge("active_connections"),
+		ServerActivePlayer:  expvarMetrics.NewGauge("server_active_player"),
+		ServerLogins:        expvarMetrics.NewCounter("server_logins"),
 	}
 }
 
@@ -83,6 +85,8 @@ func (b discardMetricsBuilder) BuildConnectorMetrics() *server.ConnectorMetrics
 		ConnectionsFrontend: discardMetrics.NewCounter(),
 		ConnectionsBackend:  discardMetrics.NewCounter(),
 		ActiveConnections:   discardMetrics.NewGauge(),
+		ServerActivePlayer:  discardMetrics.NewGauge(),
+		ServerLogins:        discardMetrics.NewCounter(),
 	}
 }
 
@@ -132,6 +136,8 @@ func (b *influxMetricsBuilder) BuildConnectorMetrics() *server.ConnectorMetrics
 		ConnectionsFrontend: c.With("side", "frontend"),
 		ConnectionsBackend:  c.With("side", "backend"),
 		ActiveConnections:   metrics.NewGauge("mc_router_connections_active"),
+		ServerActivePlayer:  metrics.NewGauge("mc_router_server_player_active"),
+		ServerLogins:        metrics.NewCounter("mc_router_server_logins"),
 	}
 }
 
@@ -178,5 +184,15 @@ func (b prometheusMetricsBuilder) BuildConnectorMetrics() *server.ConnectorMetri
 			Name:      "active_connections",
 			Help:      "The number of active connections",
 		}, nil)),
+		ServerActivePlayer: prometheusMetrics.NewGauge(promauto.NewGaugeVec(prometheus.GaugeOpts{
+			Namespace: "mc_router",
+			Name:      "server_active_player",
+			Help:      "Player is active on server",
+		}, []string{"player_name", "player_uuid", "server_address"})),
+		ServerLogins: prometheusMetrics.NewCounter(promauto.NewCounterVec(prometheus.CounterOpts{
+			Namespace: "mc_router",
+			Name:      "server_logins",
+			Help:      "The total number of player logins",
+		}, []string{"player_name", "player_uuid", "server_address"})),
 	}
 }