cloudflare-nginx.py

import requests

ipv4 = 'https://www.cloudflare.com/ips-v4'
ipv6 = 'https://www.cloudflare.com/ips-v6'

def gen_set_real_ip(url):
    resp = requests.get(url)
    lines = resp.text.splitlines()
    return '\n'.join(['set_real_ip_from {};'.format(ip) for ip in lines])

map_schema = '''map $http_cf_visitor $cf_scheme {
  '{"scheme":"http"}' http;
  '{"scheme":"https"}' https;
  default $http_x_forwarded_proto;
}
'''

conf = '\n\n'.join([
    map_schema,
    '# https://www.cloudflare.com/ips/',
    gen_set_real_ip(ipv4),
    gen_set_real_ip(ipv6),
    'real_ip_header CF-Connecting-IP;'
])

print(conf)