#!/usr/bin/env python
from novaclient import client
from os import environ
import re

"""
Script to set hostnames / IP addresses mapping
in /etc/hosts
"""

try:
    USERNAME = environ['OS_USERNAME']
    PASSWORD = environ['OS_PASSWORD']
    AUTH_URL = environ['OS_AUTH_URL']
except Exception as e:
    raise Exception("Missing one or more authentication details: %s" % e)

try:
    PROJECT_NAME = environ['OS_PROJECT_NAME']
except Exception as e:
    PROJECT_NAME = environ['OS_TENANT_NAME']

try:
    OS_CLOUD = environ['OS_CLOUDNAME']
except Exception as e:
    raise Exception("Missing OS_CLOUDNAME")

if OS_CLOUD != 'undercloud':
    raise Exception("You need to load the undercloud authentication details")


def main():

    """ Example names:
        overcloud-controller-2
        overcloud-novacompute-0 """

    # Regex to extract short name from
    full_name_regex = r'^overcloud\-(.+?)$'

    nova = client.Client('2', USERNAME, PASSWORD, PROJECT_NAME,
                         AUTH_URL, connection_pool=True)

    prep_list = dict()

    # Get all servers
    servers = nova.servers.list()

    for server in servers:

        # Get networks/IP for ctlplane
        networks = server.networks
        if ('ctlplane' in networks and len(networks['ctlplane'])):

            short_name = ''

            # Extract shortnames
            m = re.search(full_name_regex, server.name)
            if m:
                short_name_prep = m.group(1)
                short_name_prep = re.sub('-','', short_name_prep)
                short_name = re.sub('nova','', short_name_prep)

            # Save in temporary dict
            prep_list[networks['ctlplane'][0]] = server.name + ' ' + short_name

    print "Add the following to your /etc/hosts:\n"
    print '###setHostsStart###'
    for k, v in prep_list.items():
        print "%s\t%s" % (k ,v)
    print '###setHostsEnd###'

if __name__ == "__main__":
    main()