Sometimes, during the recovery of a network service, it might be useful to run a script to check when the server is online again.
We can write a client that will wait for a particular network service forever or for a timeout. In this example, by default, we would like to check when a web server is up in localhost. If you specified some other remote host or port, that information will be used instead.
Listing 3.3 shows waiting for a remote network service, as follows:
#!/usr/bin/env python
# Python Network Programming Cookbook, Second Edition -- Chapter - 3
# This program is optimized for Python 2.7.12 and Python 3.5.2.
# It may run on any other version with/without modifications.
import argparse
import socket
import errno
from time import time as now
DEFAULT_TIMEOUT = 120
DEFAULT_SERVER_HOST = 'localhost'
DEFAULT_SERVER_PORT = 80
class NetServiceChecker(object):
""" Wait for a network service to come online"""
def...