# This file is part of cloud-init. See LICENSE file for license information.

"""Generate multi-part mime messages for user-data """

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

from cloudinit import log
from cloudinit.handlers import INCLUSION_TYPES_MAP
from . import addLogHandlerCLI

NAME = 'make-mime'
LOG = log.getLogger(NAME)
EPILOG = ("Example: make-mime -a config.yaml:cloud-config "
          "-a script.sh:x-shellscript > user-data")


def file_content_type(text):
    """ Return file content type by reading the first line of the input. """
    try:
        filename, content_type = text.split(":", 1)
        return (open(filename, 'r'), filename, content_type.strip())
    except ValueError as e:
        raise argparse.ArgumentError(
            text, "Invalid value for %r" % (text)
        ) from e


def get_parser(parser=None):
    """Build or extend and arg parser for make-mime utility.

    @param parser: Optional existing ArgumentParser instance representing the
        subcommand which will be extended to support the args of this utility.

    @returns: ArgumentParser with proper argument configuration.
    """
    if not parser:
        parser = argparse.ArgumentParser()
    # update the parser's doc and add an epilog to show an example
    parser.description = __doc__
    parser.epilog = EPILOG
    parser.add_argument("-a", "--attach", dest="files", type=file_content_type,
                        action='append', default=[],
                        metavar="<file>:<content-type>",
                        help=("attach the given file as the specified "
                              "content-type"))
    parser.add_argument('-l', '--list-types', action='store_true',
                        default=False,
                        help='List support cloud-init content types.')
    parser.add_argument('-f', '--force', action='store_true',
                        default=False,
                        help='Ignore unknown content-type warnings')
    return parser


def get_content_types(strip_prefix=False):
    """ Return a list of cloud-init supported content types.  Optionally
        strip out the leading 'text/' of the type if strip_prefix=True.
    """
    return sorted([ctype.replace("text/", "") if strip_prefix else ctype
                   for ctype in INCLUSION_TYPES_MAP.values()])


def handle_args(name, args):
    """Create a multi-part MIME archive for use as user-data.  Optionally
       print out the list of supported content types of cloud-init.

    Also setup CLI log handlers to report to stderr since this is a development
    utility which should be run by a human on the CLI.

    @return 0 on success, 1 on failure.
    """
    addLogHandlerCLI(LOG, log.DEBUG if args.debug else log.WARNING)
    if args.list_types:
        print("\n".join(get_content_types(strip_prefix=True)))
        return 0

    sub_messages = []
    errors = []
    for i, (fh, filename, format_type) in enumerate(args.files):
        contents = fh.read()
        sub_message = MIMEText(contents, format_type, sys.getdefaultencoding())
        sub_message.add_header('Content-Disposition',
                               'attachment; filename="%s"' % (filename))
        content_type = sub_message.get_content_type().lower()
        if content_type not in get_content_types():
            level = "WARNING" if args.force else "ERROR"
            msg = (level + ": content type %r for attachment %s "
                   "may be incorrect!") % (content_type, i + 1)
            sys.stderr.write(msg + '\n')
            errors.append(msg)
        sub_messages.append(sub_message)
    if len(errors) and not args.force:
        sys.stderr.write("Invalid content-types, override with --force\n")
        return 1
    combined_message = MIMEMultipart()
    for msg in sub_messages:
        combined_message.attach(msg)
    print(combined_message)
    return 0


def main():
    args = get_parser().parse_args()
    return(handle_args(NAME, args))


if __name__ == '__main__':
    sys.exit(main())


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