Reads from a hard-coded serial port relying on a hard-coded message format.

can-json-logger.py

import serial

LOG_FILE = 'can-message-log.txt'

def main():
    """

    :return:
    """
    my_serial_port = serial.Serial(port='COM6',
                                   baudrate=115200,
                                   parity=serial.PARITY_NONE,
                                   stopbits=serial.STOPBITS_ONE,
                                   bytesize=serial.EIGHTBITS)

    while my_serial_port.isOpen():
        json_line = my_serial_port.read_until(terminator='\n')
        file_handler = open(LOG_FILE, 'a')
        file_handler.write(json_line + "\n")
        file_handler.close()


if __name__ == '__main__':
    main()