Synnefo » snf-image

#!/usr/bin/env python

"""Decode a json encoded string with properties

This program decodes a json encoded properties string and outputs it in a

bash sourcable way. The properties are passed to the program through a JSON

string either read from a file or from standard input and are outputed to a

target file.

"""

import sys

import os

import subprocess

import json

from StringIO import StringIO

from optparse import OptionParser

def parse_arguments(input_args):

    usage = "Usage: %prog [options] <output_file>"

    parser = OptionParser(usage=usage)

    parser.add_option("-i", "--input",

                        action="store",type='string', dest="input_file",

                        help="get input from FILE instead of stdin",

                        metavar="FILE")

    opts, args = parser.parse_args(input_args)

    if len(args) != 1:

        parser.error('output file is missing')

    output_file = args[0]

    if opts.input_file is not None:

        if not os.path.isfile(opts.input_file):

            parser.error('input file does not exist')

    return (opts.input_file, output_file)

def main():

    (input_file, output_file) = parse_arguments(sys.argv[1:])

    infh = sys.stdin if input_file is None else open(input_file, 'r')

    outfh = open(output_file, 'w')

    properties = json.load(infh)

    for key, value in properties.items():

        os.environ['SNF_IMAGE_PROPERTY_' + key] = value

    output = StringIO(subprocess.check_output(['bash', '-c', 'set']))

    for line in iter(output):

        if line.startswith('SNF_IMAGE_PROPERTY_'):

            outfh.write(line)

    infh.close()

    outfh.close()

    return 0

if __name__ == "__main__":

    sys.exit(main())

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