I couldn't get the script to work, so I put together a different one here

Sources: StackOverflow Question CloudInit Docks

I couldn't get the script to work, so I put together a different one here

#!/usr/local/bin/python
# Usage
# python utils/multi.py /path/to/cloud.cfg:text/cloud-config /path/to/script.sh:text/x-shellscript

import sys
import email
from email.mime.multipart import MIMEMultipart
from email.mime.text import MIMEText

if len(sys.argv) == 1:
    print("%s input-file:type ..." % (sys.argv[0]))
    sys.exit(1)

combined_message = MIMEMultipart()
for i in sys.argv[1:]:
    (filename, format_type) = i.split(":", 1)
    with open(filename) as fh:
        contents = fh.read()
    sub_message = MIMEText(contents, format_type, sys.getdefaultencoding())
    sub_message.add_header('Content-Disposition', 'attachment; file    name="%s"' % (filename))
    combined_message.attach(sub_message)

msg = email.message_from_string(combined_message.as_string())

for part in msg.walk():
    if part.get_content_maintype() == 'text':
        if part['Content-Transfer-Encoding'] in {'quoted-printable', 'base64'}:
            payload = part.get_payload(decode=True)
            del part['Content-Transfer-Encoding']
            part.set_payload(payload)
            email.encoders.encode_7or8bit(part)

# Send the modified message to stdout
print(msg.as_bytes().decode(encoding='UTF-8'))

Sources: StackOverflow Question CloudInit Docks