[OLD] LogicMachine firmware 2020.07

Code:
if not broker then
  broker = '127.0.0.1.'

  function multiply(mult)
    return function(value)
      local num = tonumber(value)
      if num then
        return num * mult
      else
        return value
      end
    end
  end

  -- topic to object map
  mqtt_to_object = {
    ['in/topic1'] = '1/1/1',
    ['in/topic2'] = '1/1/2',
  }

  -- optional topic value conversion function
  mqtt_to_object_conv = {
    ['in/topic1'] = multiply(100),
    ['in/topic2'] = multiply(0.01),
  }

  -- object to topic map
  object_to_mqtt = {
    ['1/1/1'] = 'out/topic1',
    ['1/1/2'] = 'out/topic2',
  }

  datatypes = {}

  grp.sender = 'mq'
  require('socket')

  for addr, _ in pairs(object_to_mqtt) do
    local obj = grp.find(addr)
    if obj then
      datatypes[ addr ] = obj.datatype
    end
  end

  mclient = require('mosquitto').new()
  mclient.ON_LOG = log

  mclient.ON_CONNECT = function(res, ...)
    log('mqtt connect status', res, ...)

    if res then
      for topic, _ in pairs(mqtt_to_object) do
        mclient:subscribe(topic)
      end
    else
      mclient:disconnect()
    end
  end

  mclient.ON_MESSAGE = function(mid, topic, payload)
    local addr = mqtt_to_object[ topic ]
    if addr then
      local fn = mqtt_to_object_conv[ topic ]

      if fn then
        payload = fn(payload)
      end

      grp.write(addr, payload)
    end
  end

  mclient.ON_DISCONNECT = function(...)
    log('mqtt disconnect', ...)
    mclientfd = nil
  end

  function mconnect()
    local fd

    mclient:connect(broker)
    fd = mclient:socket()

    -- fd ref is valid
    if fd then
      mclientfd = fd
    end
  end

  mconnect()

  function publishvalue(event)
    -- message from us or client is not connected
    if event.sender == 'mq' or not mclientfd then
      return
    end

    local addr = event.dst
    local dpt = datatypes[ addr ]
    local topic = object_to_mqtt[ addr ]

    -- unknown object
    if not dpt or not topic then
      return
    end

    local value = busdatatype.decode(event.datahex, dpt)
    if value ~= nil then
      if type(value) == 'boolean' then
        value = value and 1 or 0
      end

      mclient:publish(topic, tostring(value))
    end
  end

  lbclient = require('localbus').new(1)
  lbclient:sethandler('groupwrite', publishvalue)

  lbclientfd = socket.fdmaskset(lbclient:getfd(), 'r')

  -- run timer every 5 seconds
  timer = require('timerfd').new(5)
  timerfd = socket.fdmaskset(timer:getfd(), 'r')
end

-- mqtt connected
if mclientfd then
  mclientfdset = socket.fdmaskset(mclientfd, mclient:want_write() and 'rw' or 'r')
  res, lbclientstat, timerstat, mclientstat =
      socket.selectfds(10, lbclientfd, timerfd, mclientfdset)
-- mqtt not connected
else
  res, lbclientstat, timerstat =
    socket.selectfds(10, lbclientfd, timerfd)
end

if mclientfd and mclientstat then
  if socket.fdmaskread(mclientstat) then
    mclient:loop_read()
  end

  if socket.fdmaskwrite(mclientstat) then
    mclient:loop_write()
  end
end

if lbclientstat then
  lbclient:step()
end

if timerstat then
  -- clear armed timer
  timer:read()

  if mclientfd then
    mclient:loop_misc()
  else
    mconnect()
  end
end