MM-60478: Do not invalidate session cache on user added to channel (#28142)

PR: https://github.com/mattermost/mattermost/pull/27204 fixed the issue
where `invalidateWebConnSessionCacheForUser` was not broadcasted across
the cluster. However, we became too conservative and started to invalidate
the session cache as well.

But the session cache only contains the session details for the user
and the team membership. There is no channel membership related info.

Therefore, we avoid that and improve performance as well.

https://mattermost.atlassian.net/browse/MM-60478

```release-note
NONE
```

Co-authored-by: Mattermost Build <build@mattermost.com>

server/channels/app/platform/cluster_handlers.go

@@ -17,7 +17,7 @@ func (ps *PlatformService) RegisterClusterHandlers() {
 	ps.clusterIFace.RegisterClusterMessageHandler(model.ClusterEventPublish, ps.ClusterPublishHandler)
 	ps.clusterIFace.RegisterClusterMessageHandler(model.ClusterEventUpdateStatus, ps.ClusterUpdateStatusHandler)
 	ps.clusterIFace.RegisterClusterMessageHandler(model.ClusterEventInvalidateAllCaches, ps.ClusterInvalidateAllCachesHandler)
-	ps.clusterIFace.RegisterClusterMessageHandler(model.ClusterEventInvalidateCacheForUserTeams, ps.clusterInvalidateCacheForUserTeamsHandler)
+	ps.clusterIFace.RegisterClusterMessageHandler(model.ClusterEventInvalidateWebConnCacheForUser, ps.clusterInvalidateWebConnSessionCacheForUserHandler)
 	ps.clusterIFace.RegisterClusterMessageHandler(model.ClusterEventBusyStateChanged, ps.clusterBusyStateChgHandler)
 	ps.clusterIFace.RegisterClusterMessageHandler(model.ClusterEventClearSessionCacheForUser, ps.clusterClearSessionCacheForUserHandler)
 	ps.clusterIFace.RegisterClusterMessageHandler(model.ClusterEventClearSessionCacheForAllUsers, ps.clusterClearSessionCacheForAllUsersHandler)
@@ -67,13 +67,13 @@ func (ps *PlatformService) ClusterInvalidateAllCachesHandler(msg *model.ClusterM
 	ps.InvalidateAllCachesSkipSend()
 }
 
-func (ps *PlatformService) clusterInvalidateCacheForUserTeamsHandler(msg *model.ClusterMessage) {
-	ps.invalidateWebConnSessionCacheForUser(string(msg.Data))
+func (ps *PlatformService) clusterInvalidateWebConnSessionCacheForUserHandler(msg *model.ClusterMessage) {
+	ps.invalidateWebConnSessionCacheForUserSkipClusterSend(string(msg.Data))
 }
 
 func (ps *PlatformService) ClearSessionCacheForUserSkipClusterSend(userID string) {
 	ps.ClearUserSessionCacheLocal(userID)
-	ps.invalidateWebConnSessionCacheForUser(userID)
+	ps.invalidateWebConnSessionCacheForUserSkipClusterSend(userID)
 }
 
 func (ps *PlatformService) ClearSessionCacheForAllUsersSkipClusterSend() {
@@ -103,7 +103,7 @@ func (ps *PlatformService) clusterBusyStateChgHandler(msg *model.ClusterMessage)
 	}
 }
 
-func (ps *PlatformService) invalidateWebConnSessionCacheForUser(userID string) {
+func (ps *PlatformService) invalidateWebConnSessionCacheForUserSkipClusterSend(userID string) {
 	hub := ps.GetHubForUserId(userID)
 	if hub != nil {
 		hub.InvalidateUser(userID)

server/channels/app/platform/web_hub.go

@@ -200,20 +200,11 @@ func (ps *PlatformService) InvalidateCacheForUser(userID string) {
 	ps.Store.User().InvalidateProfileCacheForUser(userID)
 }
 
-func (ps *PlatformService) InvalidateChannelCacheForUser(userID string) {
-	ps.Store.Channel().InvalidateAllChannelMembersForUser(userID)
-	ps.ClearUserSessionCache(userID)
-
-	ps.Store.User().InvalidateProfilesInChannelCacheByUser(userID)
-}
-
-func (ps *PlatformService) InvalidateCacheForUserTeams(userID string) {
-	ps.invalidateWebConnSessionCacheForUser(userID)
-	ps.Store.Team().InvalidateAllTeamIdsForUser(userID)
-
+func (ps *PlatformService) invalidateWebConnSessionCacheForUser(userID string) {
+	ps.invalidateWebConnSessionCacheForUserSkipClusterSend(userID)
 	if ps.clusterIFace != nil {
 		msg := &model.ClusterMessage{
-			Event:    model.ClusterEventInvalidateCacheForUserTeams,
+			Event:    model.ClusterEventInvalidateWebConnCacheForUser,
 			SendType: model.ClusterSendBestEffort,
 			Data:     []byte(userID),
 		}
@@ -221,6 +212,18 @@ func (ps *PlatformService) InvalidateCacheForUserTeams(userID string) {
 	}
 }
 
+func (ps *PlatformService) InvalidateChannelCacheForUser(userID string) {
+	ps.Store.Channel().InvalidateAllChannelMembersForUser(userID)
+	ps.invalidateWebConnSessionCacheForUser(userID)
+	ps.Store.User().InvalidateProfilesInChannelCacheByUser(userID)
+}
+
+func (ps *PlatformService) InvalidateCacheForUserTeams(userID string) {
+	ps.invalidateWebConnSessionCacheForUser(userID)
+	// This method has its own cluster broadcast hidden inside localcachelayer.
+	ps.Store.Team().InvalidateAllTeamIdsForUser(userID)
+}
+
 // UpdateWebConnUserActivity sets the LastUserActivityAt of the hub for the given session.
 func (ps *PlatformService) UpdateWebConnUserActivity(session model.Session, activityAt int64) {
 	hub := ps.GetHubForUserId(session.UserId)

server/enterprise/metrics/metrics.go

@@ -467,7 +467,7 @@ func New(ps *platform.PlatformService, driver, dataSource string) *MetricsInterf
 		model.ClusterEventInvalidateCacheForChannel,
 		model.ClusterEventInvalidateCacheForChannelGuestCount,
 		model.ClusterEventInvalidateCacheForUser,
-		model.ClusterEventInvalidateCacheForUserTeams,
+		model.ClusterEventInvalidateWebConnCacheForUser,
 		model.ClusterEventClearSessionCacheForUser,
 		model.ClusterEventInvalidateCacheForRoles,
 		model.ClusterEventInvalidateCacheForRolePermissions,

server/public/model/cluster_message.go

@@ -16,7 +16,7 @@ const (
 	ClusterEventInvalidateCacheForChannel                   ClusterEvent = "inv_channel"
 	ClusterEventInvalidateCacheForChannelGuestCount         ClusterEvent = "inv_channel_guest_count"
 	ClusterEventInvalidateCacheForUser                      ClusterEvent = "inv_user"
-	ClusterEventInvalidateCacheForUserTeams                 ClusterEvent = "inv_user_teams"
+	ClusterEventInvalidateWebConnCacheForUser               ClusterEvent = "inv_user_teams"
 	ClusterEventClearSessionCacheForUser                    ClusterEvent = "clear_session_user"
 	ClusterEventInvalidateCacheForRoles                     ClusterEvent = "inv_roles"
 	ClusterEventInvalidateCacheForRolePermissions           ClusterEvent = "inv_role_permissions"