Include websocket users metric (#14020)

This commit adds new metrics to know the number of registered users
we have in every WebSocket broadcasts hub

app/web_hub.go

@@ -161,6 +161,9 @@ func (a *App) GetHubForUserId(userId string) *Hub {
 func (a *App) HubRegister(webConn *WebConn) {
 	hub := a.GetHubForUserId(webConn.UserId)
 	if hub != nil {
+		if metrics := a.Metrics(); metrics != nil {
+			metrics.IncrementWebSocketBroadcastUsersRegistered(strconv.Itoa(hub.connectionIndex), 1)
+		}
 		hub.Register(webConn)
 	}
 }
@@ -168,6 +171,9 @@ func (a *App) HubRegister(webConn *WebConn) {
 func (a *App) HubUnregister(webConn *WebConn) {
 	hub := a.GetHubForUserId(webConn.UserId)
 	if hub != nil {
+		if metrics := a.Metrics(); metrics != nil {
+			metrics.DecrementWebSocketBroadcastUsersRegistered(strconv.Itoa(hub.connectionIndex), 1)
+		}
 		hub.Unregister(webConn)
 	}
 }

einterfaces/metrics.go

@@ -39,6 +39,8 @@ type MetricsInterface interface {
 	IncrementWebSocketBroadcast(eventType string)
 	IncrementWebSocketBroadcastBufferSize(hub string, amount float64)
 	DecrementWebSocketBroadcastBufferSize(hub string, amount float64)
+	IncrementWebSocketBroadcastUsersRegistered(hub string, amount float64)
+	DecrementWebSocketBroadcastUsersRegistered(hub string, amount float64)
 
 	AddMemCacheHitCounter(cacheName string, amount float64)
 	AddMemCacheMissCounter(cacheName string, amount float64)

einterfaces/mocks/MetricsInterface.go

@@ -26,6 +26,11 @@ func (_m *MetricsInterface) DecrementWebSocketBroadcastBufferSize(hub string, am
 	_m.Called(hub, amount)
 }
 
+// DecrementWebSocketBroadcastUsersRegistered provides a mock function with given fields: hub, amount
+func (_m *MetricsInterface) DecrementWebSocketBroadcastUsersRegistered(hub string, amount float64) {
+	_m.Called(hub, amount)
+}
+
 // IncrementChannelIndexCounter provides a mock function with given fields:
 func (_m *MetricsInterface) IncrementChannelIndexCounter() {
 	_m.Called()
@@ -151,6 +156,11 @@ func (_m *MetricsInterface) IncrementWebSocketBroadcastBufferSize(hub string, am
 	_m.Called(hub, amount)
 }
 
+// IncrementWebSocketBroadcastUsersRegistered provides a mock function with given fields: hub, amount
+func (_m *MetricsInterface) IncrementWebSocketBroadcastUsersRegistered(hub string, amount float64) {
+	_m.Called(hub, amount)
+}
+
 // IncrementWebhookPost provides a mock function with given fields:
 func (_m *MetricsInterface) IncrementWebhookPost() {
 	_m.Called()