#!/usr/bin/env python3
# -*- coding: utf-8 -*-
# Copyright 2017, Florent Thiery
'''
Checks that DNS records are provided by the customer servers
'''
import subprocess
import os
import sys
import imp

GREEN = '\033[92m'
RED = '\033[91m'
DEF = '\033[0m'

def get_dns_servers():
    servers = list()
    with open('/etc/resolv.conf', 'r') as f:
        d = f.read().strip()
        for l in d.split('\n'):
            if l.startswith('nameserver '):
                servers.append(l.split('nameserver ')[1])
    return servers

resolvers = get_dns_servers()

def get_result(output):
    for line in output.split('\n'):
        if "has address " in line:
            return line.split("has address ")[1]

def check_dns(hostname):
    all_ok = True
    for resolver in resolvers:
        status, output = subprocess.getstatusoutput("host %s %s" % (hostname, resolver))
        success = (status == 0)
        if success:
            color = GREEN
            address = get_result(output)
        else:
            color = RED
            all_ok = False
            address = "FAIL"
        print('%sDNS resolution of %s on server %s returned %s%s' % (color, hostname, resolver, address, DEF))
    return all_ok

if os.path.isfile('../utils.py'):
    all_ok = True
    es_utils = imp.load_source('es_utils', '../utils.py')
    conf = es_utils.load_conf()
    servers = (
        'MS_SERVER_NAME',
        'MONITOR_SERVER_NAME',
        'CM_SERVER_NAME',
    )
    for s in servers:
        hostname = conf.get('MS_SERVER_NAME')
        ok = check_dns(hostname)
        if not ok:
            all_ok = False

if not all_ok:
    sys.exit(1)
else:
    sys.exit(0)