Rocket.Chat/server/startup/presence.js

import { Meteor } from 'meteor/meteor';
import { UserPresence } from 'meteor/konecty:user-presence';

import InstanceStatusModel from '../../app/models/server/models/InstanceStatus';
import UsersSessionsModel from '../../app/models/server/models/UsersSessions';

Meteor.startup(function() {
	UserPresence.start();

	const startMonitor = typeof process.env.DISABLE_PRESENCE_MONITOR === 'undefined'
		|| !['true', 'yes'].includes(String(process.env.DISABLE_PRESENCE_MONITOR).toLowerCase());
	if (startMonitor) {
		// UserPresenceMonitor.start();

		// Remove lost connections
		const ids = InstanceStatusModel.find({}, { fields: { _id: 1 } }).fetch().map((id) => id._id);

		const update = {
			$pull: {
				connections: {
					instanceId: {
						$nin: ids,
					},
				},
			},
		};
		UsersSessionsModel.update({}, update, { multi: true });
	}
});