linkspeed.py

def get_link_speed(network_interface):
    """
    This will find the link speed for a given network device.  Returns None
    if an error occurs.
    :param network_interface:
    :return: LinkSpeed or None if an error occurs.
    """
    speed_path = os.path.join(os.sep, 'sys', 'class', 'net',
                              network_interface, 'speed')
    # I'm not sure where else we'd check if this doesn't exist
    if not os.path.exists(speed_path):
        return LinkSpeed.UNKNOWN

    try:
        with open(speed_path, 'r') as sysfs:
            speed = sysfs.readlines()

            # Did we actually read anything?
            if not speed:
                return LinkSpeed.UNKNOWN

            # Try to find a sysctl match for this particular speed
            for name, member in LinkSpeed.__members__.items():
                if member.value == int(speed[0].strip()):
                    return member
            # Default to UNKNOWN if we can't find a match
            return LinkSpeed.UNKNOWN
    except IOError as e:
        log("Unable to open {path} because of error: {error}".format(
            path=speed_path,
            error=e.message,
        ))
        return LinkSpeed.UNKNOWN