jitsi-meet/resources/prosody-plugins/mod_muc_cleanup_backend_services.lua

-- Module to be enabled under main muc component
-- Clean up the room in case it is empty and has only jibri and jigasi-transcriber left in the meeting

local util = module:require 'util';
local is_admin = util.is_admin;
local is_transcriber = util.is_transcriber;
local is_jibri = util.is_jibri;

local EMPTY_TIMEOUT = module:get_option_number('services_empty_meeting_timeout', 20);

module:hook('muc-occupant-joined', function (event)
    local room = event.room;
    local occupant = event.occupant;

    if is_healthcheck_room(room.jid) or is_admin(occupant.bare_jid) then
        return;
    end

    -- clear the timer when someone joins
    if not is_jibri(occupant.jid) and not is_transcriber(occupant.jid) and room.empty_destroy_timer then
        room.empty_destroy_timer:stop();
        room.empty_destroy_timer = nil;
    end
end, -100); -- make sure we are last in the chain

module:hook('muc-occupant-left', function (event)
    local occupant, room = event.occupant, event.room;

    if is_admin(occupant.bare_jid) or is_jibri(occupant.jid) or is_transcriber(occupant.jid)
        or room._data.breakout_rooms_active then
        return;
    end

    for _, o in room:each_occupant() do
        if not is_jibri(o.jid) and not is_transcriber(o.jid)
            and not is_admin(o.bare_jid) then
            -- not empty
            return;
        end
    end

    -- seems the room only has jibri and transcriber, add a timeout to destroy the room
    room.empty_destroy_timer = module:add_timer(EMPTY_TIMEOUT, function()
        room:destroy(nil, 'Empty room with recording and/or transcribing.');

        module:log('info',
            'the conference terminated %s as being empty for %s seconds with recording/transcribing enabled',
            room.jid, EMPTY_TIMEOUT);
    end)
end, -100); -- the last thing to execute

module:hook('muc-room-destroyed', function (event)
    local room = event.room;
    if room.empty_destroy_timer then
        room.empty_destroy_timer:stop();
        room.empty_destroy_timer = nil;
    end
end, 1); -- prosody handles it at 0