Generic TCP Server for external requests

Code:
require('copas')

--[[
Resident script for TCP server
Manage client connexions
Receive requests from clients
Also send events through tcpQ storage

debug variables are set in the user library
]]--

--communication port to listen on
local tcp_port = 6789

if (tcp_debug) then
  alert ("TCP Server start")
end


-- send a message to the peers
function tcp_sendmessage(message)
  if (tcp_debug_tcp) then
    alert ("tcp_sendmessage : ".. message)
     end
  for id, sock in pairs(tcp_clients) do
    sock:send(message .. '\r\n')
  end
end

    
-- incoming data handler, manage each message sent by clients to LM
function tcp_datahandler(sock, data)
  local ip, port
  ip, port = sock:getpeername()
    
  if tcp_debug_tcp then
    alert('tcp_datahandler receive data from %s:%d - %s', ip, port, data)
  end

-- add your code to process data

end


-- connection handler, manage new peers
function tcp_connhandler(sock)

  -- enable keep-alive to check for disconnect events
  sock:setoption('keepalive', true)

  local ip, port, data, err, id

  -- get ip and port from socket
  ip, port = sock:getpeername()

  -- client id
  id = string.format('%s:%d', ip, port)

  alert('tcp_connhandler connection from %s', id)

  -- save socket reference
  tcp_clients[ id ] = sock

  -- main reader loop
  while true do
    -- wait for single line of data (until \n, \r is ignored)
    data, err = copas.receive(sock, '*l')

    -- error while receiving
    if err then
      alert('tcp_connhandler closed connection from %s:%d', ip, port)
      -- remove socket reference
      tcp_clients[ id ] = nil
      return
    end

    -- handle data frame
    tcp_datahandler(sock, data)
  end
end



-- init server handler
if not tcp_ready then
  
  if (tcp_debug) then
    alert ("TCP Server init start")
  end

     -- list of client sockets
  tcp_clients = {}

  --variable for the queue
  tcp_Q = {}
  --empty the storage queue
  storage.set('tcpQ', tcp_Q)

  -- bind to port
  tcp_tcpserver = socket.bind('*', tcp_port)

  -- error while binding, try again later
  if not tcp_tcpserver then
    os.sleep(5)
    error('tcp server realization init error: cannot bind')
  end

  -- set server connection handler
  copas.addserver(tcp_tcpserver, tcp_connhandler)

  tcp_ready = true
  
  if (tcp_debug) then
    alert ("TCP Server init end")
     end
end

-- loop to manage packets
while true do

  --retreive the queue
  tcp_Q = storage.get('tcpQ')
  storage.set('tcpQ', {})

  --sending the queue
  for index, value in ipairs(tcp_Q) do
    if tcp_debug then
         alert("TCP Server sending item "..tostring(index).." : "..tostring(value))
    end
    tcp_sendmessage(value)
  end

  --wait for tcp request during 0.1s
  copas.step(0.1)
end

if (tcp_debug) then
  alert ("TCP Server closed")
end