parse_mappings.py

def _parse_block_device_mappings(user_input):
    """
    Parse block device mappings per AWS CLI tools syntax (modified to add IOPS)

    http://docs.aws.amazon.com/AWSEC2/latest/UserGuide/block-device-mapping-concepts.html

    Syntax:
    /dev/xvd[a-z]=[snapshot-id|ephemeral]:[size in GB]:[Delete on Term]:[IOPS]
    - Leave inapplicable fields blank
    - Delete on Termination defaults to True
    - IOPS limits are not validated
    - EBS sizing is not validated

    Mount an Ephemeral Drive:
    /dev/xvdb1=ephemeral0

    Mount multiple Ephemeral Drives:
    /dev/xvdb1=ephemeral0,/dev/xvdb2=ephemeral1

    Mount a Snapshot:
    /dev/xvdp=snap-1234abcd

    Mount a Snapshot to a 100GB drive:
    /dev/xvdp=snap-1234abcd:100

    Mount a Snapshot to a 100GB drive and do not delete on termination:
    /dev/xvdp=snap-1234abcd:100:false

    Mount a Fresh 100GB EBS device
    /dev/xvdp=:100

    Mount a Fresh 100GB EBS Device and do not delete on termination:
    /dev/xvdp=:100:false

    Mount a Fresh 100GB EBS Device with 1000 IOPS
    /dev/xvdp=:100::1000
    """
    block_device_map = BlockDeviceMapping()
    mappings = user_input.split(",")
    for mapping in mappings:
        mount_point, drive = mapping.split("=")
        block_type = BlockDeviceType()
        if "ephemeral" in drive:
            pass
        elif "snapshot" in drive:
            pass
        elif ":" in drive:
            pass
        else:
            pass
        block_device_map[mount_point] = block_type