#! /usr/bin/env python3
#
# Uses GET, PUT, and POST requests in the Infoblox RESTful Web API (WAPI) to
# either create a new Host record or add an IP to an existing Host record.
#
# Requires ipam.py
#
# Author: dmrz

import argparse
import ipaddress
import sys

argparser = argparse.ArgumentParser(
    formatter_class=argparse.RawDescriptionHelpFormatter,
    description="""
Creates a new Host record with the specified primary fqdn and IP.  If a Host
record already exists with the specified fqdn, adds IP to that Host record
instead.  If IP is already registered to another Host, aborts with a warning.
""",
    epilog="""
Examples:
 %(prog)s foo.sandbox.illinois.edu 192.168.0.5
 %(prog)s foo.sandbox.illinois.edu 2001:db8::5
""")
argparser.add_argument('fqdn', help='a fully-qualified domain name')
argparser.add_argument('ip', help='an IPv4 or IPv6 address')
args = argparser.parse_args()


### interesting work starts here

import ipam

s = ipam.Session(
        # Comment this out if you don't want to see debugging
        debug_enable=1
        )
WAPI = s.WAPI  # used in request URLs below


def add_host_ip(fqdn, ipaddr):
    ip = ipaddress.ip_address(ipaddr)

    # check if IP already has a Host
    if ip.version == 4:
        response = s.get(WAPI+'/record:host', params={
            'ipv4addr': ipaddr,
            '_return_fields': ['name']
            })
    else:
        response = s.get(WAPI+'/record:host', params={
            # search is picky about IPv6 spelling
            'ipv6addr': ip.compressed,
            '_return_fields': ['name']
            })
    existing_hosts_for_ip = response.json()
    for host in existing_hosts_for_ip:
        name = host['name']
        sys.exit("Abort: IP '{}' already in use by Host '{}', "
                "creating another Host would result in duplicate PTRs"
                .format(ipaddr, name))

    # check if Host already exists (note ':' for case-insensitive search)
    existing_hosts_for_fqdn = s.get(WAPI+'/record:host', params={
        'name:': fqdn
        }).json()
    if existing_hosts_for_fqdn:
        # use PUT to modify the existing Host record (note special '+' behavior
        # supported by these fields to add a new IP without altering others)
        host = existing_hosts_for_fqdn[0]
        hostref = host['_ref']
        if ip.version == 4:
            s.put(WAPI+'/'+hostref, json={
                "ipv4addrs+": [{"ipv4addr": ipaddr}]
                })
        else:
            s.put(WAPI+'/'+hostref, json={
                "ipv6addrs+": [{"ipv6addr": ipaddr}]
                })
        print("Added IP '{}' to Host '{}'".format(ipaddr, fqdn))
    else:
        # use POST to create a new Host record
        if ip.version == 4:
            s.post(WAPI+'/record:host', json={
                "name": fqdn,
                "ipv4addrs": [{"ipv4addr": ipaddr}]
                })
        else:
            s.post(WAPI+'/record:host', json={
                "name": fqdn,
                "ipv6addrs": [{"ipv6addr": ipaddr}]
                })
        print("Created new Host '{}'".format(fqdn))


add_host_ip(args.fqdn, args.ip)