main.py

import json
import netaddr
import urllib.request

goog_url="https://www.gstatic.com/ipranges/goog.json"
cloud_url="https://www.gstatic.com/ipranges/cloud.json"

def read_url(url):
   try:
      s = urllib.request.urlopen(url).read()
      return json.loads(s)
   except urllib.error.HTTPError:
      print("Invalid HTTP response from %s" % url)
      return {}
   except json.decoder.JSONDecodeError:
      print("Could not parse HTTP response from %s" % url)
      return {}

def main():
   goog_json=read_url(goog_url)
   cloud_json=read_url(cloud_url)

   if goog_json and cloud_json:
      print("{} published: {}".format(goog_url,goog_json.get('creationTime')))
      print("{} published: {}".format(cloud_url,cloud_json.get('creationTime')))
      goog_cidrs = netaddr.IPSet()
      for e in goog_json['prefixes']:
         if e.get('ipv4Prefix'):
            goog_cidrs.add(e.get('ipv4Prefix'))
      cloud_cidrs = netaddr.IPSet()
      for e in cloud_json['prefixes']:
         if e.get('ipv4Prefix'):
            cloud_cidrs.add(e.get('ipv4Prefix'))
      with open('ranges.txt', 'w') as f:
        for i in goog_cidrs.difference(cloud_cidrs).iter_cidrs():
          f.write("%s\n" % i)
      print("IP ranges for Google APIs and services default domains saved to file")

if __name__ == '__main__':
   main()