## # copyright 2009, James William Pye # http://python.projects.postgresql.org ## """ socket tools """ import random import socket import math import errno __all__ = ['find_available_port'] def find_available_port( interface : "attempt to bind to interface" = 'localhost', address_family : "address family to use (default: AF_INET)" = socket.AF_INET, limit : "Number tries to make before giving up" = 1024, port_range = (6600, 56600) ) -> (int, None): """ Find an available port on the given interface for the given address family. Returns a port number that was successfully bound to or `None` if the attempt limit was reached. """ i = 0 while i < limit: i += 1 port = ( math.floor( random.random() * (port_range[1] - port_range[0]) ) + port_range[0] ) s = socket.socket(address_family, socket.SOCK_STREAM,) try: s.bind(('localhost', port)) except socket.error as e: if e.errno in (errno.EACCES, errno.EADDRINUSE, errno.EINTR): # try again continue finally: s.close() break else: port = None return port