pvc/node-daemon/pvcd/dnsmasq-zookeeper-leases.py

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#!/usr/bin/python3
import argparse
import configparser
import os, sys
import kazoo.client
import re
#
# Variables
#
#
# General Functions
#
def get_zookeeper_key():
# Get the interface from environment (passed by dnsmasq)
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try:
interface = os.environ['DNSMASQ_INTERFACE']
except:
exit(1)
# Get the ID of the interface (the digits)
network_vni = re.findall('\d+', interface)[0]
# Create the key
zookeeper_key = '/networks/{}/dhcp_leases'.format(network_vni)
return zookeeper_key
def get_lease_expiry():
try:
expiry = os.environ['DNSMASQ_LEASE_EXPIRES']
except:
expiry = '0'
return expiry
def get_client_id():
try:
client_id = os.environ['DNSMASQ_CLIENT_ID']
except:
client_id = '*'
return client_id
def connect_zookeeper():
# We expect the environ to contain the config file
try:
pvcd_config_file = os.environ['PVCD_CONFIG_FILE']
except:
# Default place
pvcd_config_file = '/etc/pvc/pvcd.conf'
o_config = configparser.ConfigParser()
o_config.read(pvcd_config_file)
try:
zk_host = o_config['default']['coordinators']
except:
try:
zk_host = o_config[socket.gethostname()]['coordinators']
except:
exit(1)
zk_conn = kazoo.client.KazooClient(hosts=zk_host)
try:
zk_conn.start()
except:
exit(1)
return zk_conn
def read_data(zk_conn, key):
return zk_conn.get(key)[0].decode('ascii')
def get_lease(zk_conn, zk_leases_key, macaddr):
expiry = read_data(zk_conn, '{}/{}/expiry'.format(zk_leases_key, macaddr))
ipaddr = read_data(zk_conn, '{}/{}/ipaddr'.format(zk_leases_key, macaddr))
hostname = read_data(zk_conn, '{}/{}/hostname'.format(zk_leases_key, macaddr))
clientid = read_data(zk_conn, '{}/{}/clientid'.format(zk_leases_key, macaddr))
return expiry, ipaddr, hostname, clientid
#
# Command Functions
#
def read_lease_database(zk_conn, zk_leases_key):
leases_list = zk_conn.get_children(zk_leases_key)
output_list = []
for macaddr in leases_list:
expiry, ipaddr, hostname, clientid = get_lease(zk_conn, zk_leases_key, macaddr)
data_string = '{} {} {} {} {}'.format(expiry, macaddr, ipaddr, hostname, clientid)
print('Reading lease from Zookeeper: {}'.format(data_string), file=sys.stderr)
output_list.append('{}'.format(data_string))
# Output list
print('\n'.join(output_list))
def add_lease(zk_conn, zk_leases_key, expiry, macaddr, ipaddr, hostname, clientid):
transaction = zk_conn.transaction()
transaction.create('{}/{}'.format(zk_leases_key, macaddr), ''.encode('ascii'))
transaction.create('{}/{}/expiry'.format(zk_leases_key, macaddr), expiry.encode('ascii'))
transaction.create('{}/{}/ipaddr'.format(zk_leases_key, macaddr), ipaddr.encode('ascii'))
transaction.create('{}/{}/hostname'.format(zk_leases_key, macaddr), hostname.encode('ascii'))
transaction.create('{}/{}/clientid'.format(zk_leases_key, macaddr), clientid.encode('ascii'))
transaction.commit()
def del_lease(zk_conn, zk_leases_key, macaddr, expiry):
zk_conn.delete('{}/{}'.format(zk_leases_key, macaddr), recursive=True)
#
# Instantiate the parser
#
parser = argparse.ArgumentParser(description='Store or retrieve dnsmasq leases in Zookeeper')
parser.add_argument('action', type=str, help='Action')
parser.add_argument('macaddr', type=str, help='MAC Address', nargs='?', default=None)
parser.add_argument('ipaddr', type=str, help='IP Address', nargs='?', default=None)
parser.add_argument('hostname', type=str, help='Hostname', nargs='?', default=None)
args = parser.parse_args()
action = args.action
macaddr = args.macaddr
ipaddr = args.ipaddr
hostname = args.hostname
zk_conn = connect_zookeeper()
zk_leases_key = get_zookeeper_key()
if action == 'init':
read_lease_database(zk_conn, zk_leases_key)
exit(0)
expiry = get_lease_expiry()
clientid = get_client_id()
#
# Choose action
#
print('Lease action - {} {} {} {}'.format(action, macaddr, ipaddr, hostname), file=sys.stderr)
if action == 'add':
add_lease(zk_conn, zk_leases_key, expiry, macaddr, ipaddr, hostname, clientid)
elif action == 'del':
del_lease(zk_conn, zk_leases_key, macaddr, expiry)
elif action == 'old':
pass