guess_ports.py

#!/usr/bin/env python
import logging
import random
import socket
import sys
import urllib

HOST = "localhost"
PORT = 3000
N_INSTANCES = 4

logger = logging.getLogger('port_guesser')
logger.addHandler(logging.StreamHandler(sys.stderr))
logger.setLevel(logging.DEBUG)


def socket_exists(host, port):
    logger.info('Checking whether %s:%s is reachable' % (host, port))
    try:
        socket.create_connection([host, port])
    except socket.error:
        return False
    else:
        return True

def port_is_chunker(host, port):
    try:
        handle = urllib.urlopen("http://%s:%s" % (host, port))
        head = handle.info()
        return 'TwistedWeb' in head['server']
    except Exception:
        return False

def get_baseport(host):
    baseport = 1024
    while not socket_exists(HOST, baseport) or not port_is_chunker(HOST, baseport):
        baseport = baseport + 1
        if baseport == PORT:
            baseport = baseport + 1
    return baseport

def main():
    ports = []
    baseport = get_baseport(HOST)
    ports.append(baseport)
    for i in range(N_INSTANCES-1):
        baseport+=1
        ports.append(baseport)
    logger.info('Found chunk ports: %s' % ports)
    

if __name__ == '__main__':
    main()