Quick serial port to tcp socket muxer

serial_mux.py

#!/usr/bin/env python
import argparse, serial, socket, select

parser = argparse.ArgumentParser(description='Connect to a serial port and allow multiple TCP clients to talk to it (simultaneous output shared between all TCP clients, any client can write to port.)')
parser.add_argument('--baud', help="Baud rate", default=115200, type=int)
parser.add_argument('port', help="Port to listen on.", type=int)
parser.add_argument('serial', help="Serial port to share.")

def main():
    args = parser.parse_args()
    listen_sock = socket.socket(socket.AF_INET, socket.SOCK_STREAM)
    listen_sock.bind(('', args.port))
    listen_sock.listen(1)
    port = serial.Serial(args.serial, baudrate=args.baud)
    clients = set() # existing client connections
    while True:
        listeners = [ listen_sock, port ] + list(clients)
        pending_reads,_,_ = select.select(listeners, [], [])
        for reader in pending_reads:
            if reader == listen_sock: # new connection
                conn,_ = listen_sock.accept()
                clients.add(conn)
            elif reader == port: # new data from serial port
                data = port.read(port.inWaiting())
                for out in clients:
                    try:
                        out.send(data)
                    except socket.error:
                        clients.remove(out)
            else: # new data from a network client
                try:
                    data = reader.recv(128)
                    if len(data) == 0:
                        raise socket.error("Remove this socket")
                    port.write(data)
                except socket.error:
                    clients.remove(reader)

if __name__ == "__main__":
    main()