A simple python 3.0 script to log data from two different serial ports at one time

serial_port_logger.py

import serial
import sys
import time
import argparse

parser = argparse.ArgumentParser(description='Dump serial data from basis')
parser.add_argument('portA', type=str, help='Serial port A')
parser.add_argument('portB', type=str, help='Serial port B')
parser.add_argument('--baud', type=int, default=1000000, help='The baud rate of both devices')
parser.add_argument('--labelA', type=str, default='A')
parser.add_argument('--labelB', type=str, default='B')
parser.add_argument('--log', action='store_true', default=False)
args = parser.parse_args()

porta = serial.Serial(args.portA, args.baud, timeout=1)
portb = serial.Serial(args.portB, args.baud, timeout=1)

astr = bytearray()
bstr = bytearray()
gota = 0.0
gotb = 0.0
logfile = None

if args.log:
    logfile = open(time.strftime('serial_logfile_%d%m%y_%H%M%S.txt', time.gmtime()), 'w')

def parseLine(src, line):
    ret = []
    for byte in line:
        ret.append('%02x' % byte)
    outline = '[%.3f] %s: %s' % (time.time(), src, ''.join(ret))
    print(outline)
    if args.log:
        logfile.write(outline+'\n')
        logfile.flush()

try:
    while(True):
        while(porta.inWaiting()):
            if len(bstr) > 0:
                parseLine(args.labelB, bstr)
                bstr = bytearray()
            astr.append(ord(porta.read(1)))
            gota = time.time()
        while(portb.inWaiting()):
            if len(astr) > 0:
                parseLine(args.labelA, astr)
                astr = bytearray()
            bstr.append(ord(portb.read(1)))
            gotb = time.time()
        if (time.time() - gota > 0.9) and (len(astr) > 0):
            parseLine(args.labelA, astr)
            astr = bytearray()
        if (time.time() - gotb > 0.9) and (len(bstr) > 0):
            parseLine(args.labelB, bstr)
            bstr = bytearray()
except KeyboardInterrupt:
    porta.close()
    portb.close()
    if args.log:
        logfile.close()
    sys.exit(1)