63 lines
1.6 KiB
Python
63 lines
1.6 KiB
Python
# -*- coding: utf-8 -*-
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"""Utility functions for working with network sockets.
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Created by Sybren A. Stüvel for Chess IX, Haarlem, The Netherlands.
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Licensed under the Apache 2 license.
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"""
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import logging
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import os
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import socket
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LOG = logging.getLogger(__name__)
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def is_bindable(address):
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"""Tries to bind a listening socket to the given address.
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Returns True if this works, False otherwise. In any case the socket is
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closed before returning.
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"""
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sock = None
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try:
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sock = socket.socket()
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if os.name == 'posix':
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sock.setsockopt(socket.SOL_SOCKET, socket.SO_REUSEADDR, 1)
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sock.bind(address)
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sock.close()
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except IOError as ex:
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LOG.debug('is_bindable(%s): %s', address, ex)
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if sock:
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sock.close()
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return False
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return True
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def find_free_port(start_address):
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"""Incrementally searches for a TCP port that can be bound to.
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:param start_address: (hostname, portnr) tuple defining the host to
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bind and the portnumber to start the search
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:type start_address: tuple
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:return: the address containing the first port number that was found
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to be free.
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:rtype: tuple of (hostname, port_nr)
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"""
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(hostname, port_nr) = start_address
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LOG.debug('find_free_port(%s)', start_address)
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while not is_bindable((hostname, port_nr)):
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LOG.debug('find_free_port: %i is not bindable, trying next port', port_nr)
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port_nr += 1
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return hostname, port_nr
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def hostname() -> str:
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return socket.gethostname()
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