Debug tool for unwrapping data URLs in Ignition configs

decompile.py

#!/usr/bin/python

import gzip
import json
import sys
from urllib.request import urlopen
import yaml

class literal(str):
    pass


def literal_representer(dumper, data):
    return dumper.represent_scalar(u'tag:yaml.org,2002:str', data, style='|')
yaml.add_representer(literal, literal_representer)


def inline(resource):
    if not resource.get('source', '').startswith('data:'):
        return False

    with urlopen(resource['source']) as resp:
        data = resp.read()
    del resource['source']

    if resource.get('compression') == 'gzip':
        del resource['compression']
        data = gzip.decompress(data)

    try:
        data = data.decode()
    except UnicodeError:
        pass

    resource['inline'] = literal(data)
    return True


def convert(data):
    conf = json.loads(data)

    for item in conf.get('ignition', {}).get('config', {}).get('merge', []):
        if inline(item):
            item['inline'] = convert(item['inline'])

    for item in conf.get('ignition', {}).get('security', {}).get('tls', {}).get('certificateAuthorities', []):
        inline(item)

    for file in conf.get('storage', {}).get('files', []):
        contents = file.get('contents', {})
        if inline(contents) and file['path'].endswith('.ign'):
            contents['inline'] = convert(contents['inline'])

    for unit in conf.get('systemd', {}).get('units', []):
        contents = unit.get('contents')
        if contents:
            unit['contents'] = literal(contents)

    return literal(yaml.dump(conf))


if __name__ == '__main__':
    if len(sys.argv) > 1:
        with open(sys.argv[1]) as fh:
            data = fh.read()
    else:
        data = sys.stdin.read()
    print(convert(data), end='')