ami.py

def retrieve_ubuntu_amis(region=u'us-east-1', dist=u'raring', arch=u'amd64', store=u'ebs'):
    import requests
    import json
    from lxml import etree
    from time import time
    from StringIO import StringIO

    now = int(time())
    url = 'http://cloud-images.ubuntu.com/locator/ec2/releasesTable?_={}'.format(now)
    response = requests.get(url)
    
    # piece of shit malformed JSON
    components = response.content.split(',')
    good_JSON = ','.join(components[:-1]) + components[-1]

    the_images = json.loads(good_JSON)
    for image in the_images['aaData']:
        if image[0] == region and image[1] == dist \
            and image[3] == arch and image[4] == store:
            #crap... ami is embedded in html. LET'S PULL IT OUT!
            parser = etree.HTMLParser()
            tree   = etree.parse(StringIO(image[6]), parser)
            return tree.xpath('//a/text()')[0]