Improve websocket logging (#24259)

After reliable websockets were introduced,
we would keep pushing to a webConn even after
the client has disconnected. This would lead
to the websocket.slow/full and eventually
the disconnect messages which unnecessarily
confuse the admin.

We don't log them if the connection is inactive.

We use the active field and convert it to an atomic
to use more widely.

```release-note
NONE
```

server/channels/app/platform/web_hub.go

@@ -383,7 +383,7 @@ func (h *Hub) Start() {
 				conns := connIndex.ForUser(webSessionMessage.userID)
 				var isRegistered bool
 				for _, conn := range conns {
-					if !conn.active {
+					if !conn.active.Load() {
 						continue
 					}
 					if conn.GetSessionToken() == webSessionMessage.sessionToken {
@@ -411,7 +411,7 @@ func (h *Hub) Start() {
 				// Mark the current one as active.
 				// There is no need to check if it was inactive or not,
 				// we will anyways need to make it active.
-				webConn.active = true
+				webConn.active.Store(true)
 
 				connIndex.Add(webConn)
 				atomic.StoreInt64(&h.connectionCount, int64(connIndex.AllActive()))
@@ -426,7 +426,7 @@ func (h *Hub) Start() {
 			case webConn := <-h.unregister:
 				// If already removed (via queue full), then removing again becomes a noop.
 				// But if not removed, mark inactive.
-				webConn.active = false
+				webConn.active.Store(false)
 
 				atomic.StoreInt64(&h.connectionCount, int64(connIndex.AllActive()))
 
@@ -444,7 +444,7 @@ func (h *Hub) Start() {
 				}
 				var latestActivity int64
 				for _, conn := range conns {
-					if !conn.active {
+					if !conn.active.Load() {
 						continue
 					}
 					if conn.lastUserActivityAt > latestActivity {
@@ -464,7 +464,7 @@ func (h *Hub) Start() {
 				}
 			case activity := <-h.activity:
 				for _, webConn := range connIndex.ForUser(activity.userID) {
-					if !webConn.active {
+					if !webConn.active.Load() {
 						continue
 					}
 					if webConn.GetSessionToken() == activity.sessionToken {
@@ -478,9 +478,12 @@ func (h *Hub) Start() {
 				select {
 				case directMsg.conn.send <- directMsg.msg:
 				default:
-					mlog.Error("webhub.broadcast: cannot send, closing websocket for user",
-						mlog.String("user_id", directMsg.conn.UserId),
-						mlog.String("conn_id", directMsg.conn.GetConnectionID()))
+					// Don't log the warning if it's an inactive connection.
+					if directMsg.conn.active.Load() {
+						mlog.Error("webhub.broadcast: cannot send, closing websocket for user",
+							mlog.String("user_id", directMsg.conn.UserId),
+							mlog.String("conn_id", directMsg.conn.GetConnectionID()))
+					}
 					close(directMsg.conn.send)
 					connIndex.Remove(directMsg.conn)
 				}
@@ -497,9 +500,12 @@ func (h *Hub) Start() {
 						select {
 						case webConn.send <- msg:
 						default:
-							mlog.Error("webhub.broadcast: cannot send, closing websocket for user",
-								mlog.String("user_id", webConn.UserId),
-								mlog.String("conn_id", webConn.GetConnectionID()))
+							// Don't log the warning if it's an inactive connection.
+							if webConn.active.Load() {
+								mlog.Error("webhub.broadcast: cannot send, closing websocket for user",
+									mlog.String("user_id", webConn.UserId),
+									mlog.String("conn_id", webConn.GetConnectionID()))
+							}
 							close(webConn.send)
 							connIndex.Remove(webConn)
 						}
@@ -639,7 +645,7 @@ func (i *hubConnectionIndex) RemoveInactiveByConnectionID(userID, connectionID s
 		return nil
 	}
 	for _, conn := range i.ForUser(userID) {
-		if conn.GetConnectionID() == connectionID && !conn.active {
+		if conn.GetConnectionID() == connectionID && !conn.active.Load() {
 			i.Remove(conn)
 			return conn
 		}
@@ -652,7 +658,7 @@ func (i *hubConnectionIndex) RemoveInactiveByConnectionID(userID, connectionID s
 func (i *hubConnectionIndex) RemoveInactiveConnections() {
 	now := model.GetMillis()
 	for conn := range i.byConnection {
-		if !conn.active && now-conn.lastUserActivityAt > i.staleThreshold.Milliseconds() {
+		if !conn.active.Load() && now-conn.lastUserActivityAt > i.staleThreshold.Milliseconds() {
 			i.Remove(conn)
 		}
 	}
@@ -664,7 +670,7 @@ func (i *hubConnectionIndex) RemoveInactiveConnections() {
 func (i *hubConnectionIndex) AllActive() int {
 	cnt := 0
 	for conn := range i.byConnection {
-		if conn.active {
+		if conn.active.Load() {
 			cnt++
 		}
 	}