Get the URL for the latest LXC image. Basic processor, uses the ";" separated characteristics to search for and find the path of the image rootfs. Presently the image search is hard coded to [ ubuntu;trusty;amd64;default ] .

lxc-upstream-image-search.py

#!/usr/bin/env python

import urlparse
import requests

LXC_IMAGE_INDEX = 'https://images.linuxcontainers.org:8443/meta/1.0/index-system'
INDEX_URL = urlparse.urlparse(LXC_IMAGE_INDEX)


def main(image='ubuntu;trusty;amd64;default'):
    req = requests.get(LXC_IMAGE_INDEX)
    image_entry = [i for i in req.content.split() if image in i][0].split(';')
    image_path = urlparse.urljoin('%s://%s' %(INDEX_URL.scheme, INDEX_URL.netloc), image_entry[-1])
    if not image_path.endswith('/'):
        image_path = '%s/' % image_path

    return urlparse.urljoin(image_path, 'rootfs.tar.xz')

if __name__ == '__main__':
    print(main())