def main()

in cookbooks/aws-parallelcluster-install/files/default/ec2_udev_rules/attachVolume.py [0:0]

• 65 lines of code
• 12 McCabe index (conditional complexity)

def main():
    # Get EBS volume Id
    try:
        volume_id = str(sys.argv[1])
    except IndexError:
        print("Provide an EBS volume ID to attach i.e. vol-cc789ea5")
        sys.exit(1)

    # Get IMDSv2 token
    token = get_imdsv2_token()

    # Get instance ID
    instance_id = requests.get("http://169.254.169.254/latest/meta-data/instance-id", headers=token).text

    # Get region
    region = requests.get("http://169.254.169.254/latest/meta-data/placement/availability-zone", headers=token).text
    region = region[:-1]

    # Generate a list of system paths minus the root path
    paths = [convert_dev(device) for device in get_all_devices()]

    # List of possible block devices
    block_devices = [
        "/dev/sdb",
        "/dev/sdc",
        "/dev/sdd",
        "/dev/sde",
        "/dev/sdf",
        "/dev/sdg",
        "/dev/sdh",
        "/dev/sdi",
        "/dev/sdj",
        "/dev/sdk",
        "/dev/sdl",
        "/dev/sdm",
        "/dev/sdn",
        "/dev/sdo",
        "/dev/sdp",
        "/dev/sdq",
        "/dev/sdr",
        "/dev/sds",
        "/dev/sdt",
        "/dev/sdu",
        "/dev/sdv",
        "/dev/sdw",
        "/dev/sdx",
        "/dev/sdy",
        "/dev/sdz",
    ]

    # List of available block devices after removing currently used block devices
    available_devices = [a for a in block_devices if a not in paths]

    # Parse configuration file to read proxy settings
    config = configparser.RawConfigParser()
    config.read("/etc/boto.cfg")
    proxy_config = Config()
    if config.has_option("Boto", "proxy") and config.has_option("Boto", "proxy_port"):
        proxy = config.get("Boto", "proxy")
        proxy_port = config.get("Boto", "proxy_port")
        proxy_config = Config(proxies={"https": "{0}:{1}".format(proxy, proxy_port)})

    # Connect to AWS using boto
    ec2 = boto3.client("ec2", region_name=region, config=proxy_config)

    # Attach the volume
    dev = available_devices[0]
    response = ec2.attach_volume(VolumeId=volume_id, InstanceId=instance_id, Device=dev)

    # Poll for volume to attach
    state = response.get("State")
    x = 0
    while state != "attached":
        if x == 60:
            print("Volume %s failed to mount in 300 seconds." % volume_id)
            exit(1)
        if state in ["busy", "detached"]:
            print("Volume %s in bad state %s" % (volume_id, state))
            exit(1)
        print("Volume %s in state %s ... waiting to be 'attached'" % (volume_id, state))
        time.sleep(5)
        x += 1
        try:
            state = ec2.describe_volumes(VolumeIds=[volume_id]).get("Volumes")[0].get("Attachments")[0].get("State")
        except IndexError:
            continue