[MM-36198] - Activating a user in System Console does not respect cloud user limits (#17719)

* [MM-36198] - Activating a user in System Console does not respect cloud user limits

* feedback impl

* improve error check

app/app_iface.go

@@ -428,6 +428,7 @@ type AppIface interface {
 	ChannelMembersToRemove(teamID *string) ([]*model.ChannelMember, *model.AppError)
 	CheckAndSendUserLimitWarningEmails(c *request.Context) *model.AppError
 	CheckCanInviteToSharedChannel(channelId string) error
+	CheckCloudAccountAtLimit() (bool, *model.AppError)
 	CheckForClientSideCert(r *http.Request) (string, string, string)
 	CheckIntegrity() <-chan model.IntegrityCheckResult
 	CheckMandatoryS3Fields(settings *model.FileSettings) *model.AppError
@@ -734,6 +735,7 @@ type AppIface interface {
 	GetStatus(userID string) (*model.Status, *model.AppError)
 	GetStatusFromCache(userID string) *model.Status
 	GetStatusesByIds(userIDs []string) (map[string]interface{}, *model.AppError)
+	GetSubscriptionStats() (*model.SubscriptionStats, *model.AppError)
 	GetTeam(teamID string) (*model.Team, *model.AppError)
 	GetTeamByInviteId(inviteId string) (*model.Team, *model.AppError)
 	GetTeamByName(name string) (*model.Team, *model.AppError)

app/cloud.go

@@ -79,6 +79,52 @@ func (a *App) SendAdminUpgradeRequestEmail(username string, subscription *model.
 	return nil
 }
 
+func (a *App) GetSubscriptionStats() (*model.SubscriptionStats, *model.AppError) {
+	if a.Srv().License() == nil || !*a.Srv().License().Features.Cloud {
+		return nil, model.NewAppError("app.GetSubscriptionStats", "api.cloud.license_error", nil, "", http.StatusInternalServerError)
+	}
+
+	subscription, appErr := a.Cloud().GetSubscription("")
+	if appErr != nil {
+		return nil, model.NewAppError("app.GetSubscriptionStats", "api.cloud.request_error", nil, appErr.Error(), http.StatusInternalServerError)
+	}
+
+	count, err := a.Srv().Store.User().Count(model.UserCountOptions{})
+	if err != nil {
+		return nil, model.NewAppError("app.GetSubscriptionStats", "app.user.get_total_users_count.app_error", nil, err.Error(), http.StatusInternalServerError)
+	}
+	cloudUserLimit := *a.Config().ExperimentalSettings.CloudUserLimit
+
+	s := cloudUserLimit - count
+
+	return &model.SubscriptionStats{
+		RemainingSeats: int(s),
+		IsPaidTier:     subscription.IsPaidTier,
+	}, nil
+}
+
+func (a *App) CheckCloudAccountAtLimit() (bool, *model.AppError) {
+	if a.Srv().License() == nil || (a.Srv().License() != nil && !*a.Srv().License().Features.Cloud) {
+		// Not cloud instance, so no at limit checks
+		return false, nil
+	}
+
+	stats, err := a.GetSubscriptionStats()
+	if err != nil {
+		return false, err
+	}
+
+	if stats.IsPaidTier == "true" {
+		return false, nil
+	}
+
+	if stats.RemainingSeats < 1 {
+		return true, nil
+	}
+
+	return false, nil
+}
+
 func (a *App) CheckAndSendUserLimitWarningEmails(c *request.Context) *model.AppError {
 	if a.Srv().License() == nil || (a.Srv().License() != nil && !*a.Srv().License().Features.Cloud) {
 		// Not cloud instance, do nothing

app/opentracing/opentracing_layer.go

@@ -1134,6 +1134,28 @@ func (a *OpenTracingAppLayer) CheckCanInviteToSharedChannel(channelId string) er
 	return resultVar0
 }
 
+func (a *OpenTracingAppLayer) CheckCloudAccountAtLimit() (bool, *model.AppError) {
+	origCtx := a.ctx
+	span, newCtx := tracing.StartSpanWithParentByContext(a.ctx, "app.CheckCloudAccountAtLimit")
+
+	a.ctx = newCtx
+	a.app.Srv().Store.SetContext(newCtx)
+	defer func() {
+		a.app.Srv().Store.SetContext(origCtx)
+		a.ctx = origCtx
+	}()
+
+	defer span.Finish()
+	resultVar0, resultVar1 := a.app.CheckCloudAccountAtLimit()
+
+	if resultVar1 != nil {
+		span.LogFields(spanlog.Error(resultVar1))
+		ext.Error.Set(span, true)
+	}
+
+	return resultVar0, resultVar1
+}
+
 func (a *OpenTracingAppLayer) CheckForClientSideCert(r *http.Request) (string, string, string) {
 	origCtx := a.ctx
 	span, newCtx := tracing.StartSpanWithParentByContext(a.ctx, "app.CheckForClientSideCert")
@@ -8748,6 +8770,28 @@ func (a *OpenTracingAppLayer) GetStatusesByIds(userIDs []string) (map[string]int
 	return resultVar0, resultVar1
 }
 
+func (a *OpenTracingAppLayer) GetSubscriptionStats() (*model.SubscriptionStats, *model.AppError) {
+	origCtx := a.ctx
+	span, newCtx := tracing.StartSpanWithParentByContext(a.ctx, "app.GetSubscriptionStats")
+
+	a.ctx = newCtx
+	a.app.Srv().Store.SetContext(newCtx)
+	defer func() {
+		a.app.Srv().Store.SetContext(origCtx)
+		a.ctx = origCtx
+	}()
+
+	defer span.Finish()
+	resultVar0, resultVar1 := a.app.GetSubscriptionStats()
+
+	if resultVar1 != nil {
+		span.LogFields(spanlog.Error(resultVar1))
+		ext.Error.Set(span, true)
+	}
+
+	return resultVar0, resultVar1
+}
+
 func (a *OpenTracingAppLayer) GetSuggestions(c *request.Context, commandArgs *model.CommandArgs, commands []*model.Command, roleID string) []model.AutocompleteSuggestion {
 	origCtx := a.ctx
 	span, newCtx := tracing.StartSpanWithParentByContext(a.ctx, "app.GetSuggestions")