helper script to wait until some process is listening to a given TCP port

waitfor.py

#!/usr/bin/python

from socket import socket, gethostbyname, AF_INET, SOCK_STREAM
from sys import argv, exit
from time import sleep


def waitfor(*ports, **kw):
    timeout = kw.get('timeout', 30)
    host = kw.get('host', 'localhost')
    ip = gethostbyname(host)
    ports = set(*ports)
    while ports and timeout > 0:
        for port in list(ports):
            s = socket(AF_INET, SOCK_STREAM)
            if s.connect_ex((ip, port)) == 0:
                ports.remove(port)
            s.close()
        if ports:
            sleep(1)
            timeout -= 1
    return not bool(ports)


if __name__ == '__main__':
    exit(not waitfor(map(int, argv[1:])))   # False is 0 for `exit`!