libvirt kvm ansible dynamic inventory script

inventory.py

#! /usr/bin/python

import re
import sys
import subprocess as sub
import json

res = sub.Popen(["virsh", "net-dhcp-leases", "default"], stdout=sub.PIPE)
output, err = res.communicate()

# todo: make the regex work for hosts that don't start with node
nodes = []
for l in output.splitlines():
    r = re.match(r"^.* (\d+.\d+.\d+.\d+)/\d+.*(node\w+)\s+01:.*$", l)
    if r:
        nodes.append(r.group(1))

result = {
    "all": {
        "hosts": nodes
    }
}

if len(sys.argv) == 2 and sys.argv[1] == '--list':
    print(json.dumps(result))
elif len(sys.argv) == 3 and sys.argv[1] == '--host':
    result = {
        "ansible_ssh_user": "root",
        "ansible_connection": "ssh"
        # .. empty
    }
    print(json.dumps(result))
else:
    sys.stderr.write("Need an argument, either --list or --host <host>\n")