Demo of circular dependencies created while using TLSMemoryBIOProtocol

twisted_refcycle_test.py

import sys
import os
import gc

from twisted.protocols.tls import TLSMemoryBIOFactory, TLSMemoryBIOProtocol
from twisted.internet.protocol import Protocol, Factory
from twisted.internet import ssl, defer, error
from twisted.internet.task import react
from twisted.protocols.loopback import loopbackAsync
import psutil


N = 10000
K = 100
print('N =', N, ', K =', K)


class DummyServerProtocol(Protocol):
    def dataReceived(self, data):
        self.transport.loseConnection()


class DummyClientProtocol(Protocol):
    def connectionMade(self):
        self.transport.write(b'hello')

    def connectionLost(self, reason):
        reason.trap(error.ConnectionDone)


cert='\n-----BEGIN CERTIFICATE-----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\nO08ok5x1jZ1jbd5B3QAuYsowWOo=\n-----END CERTIFICATE-----\n'
key='-----BEGIN PRIVATE KEY-----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\nbEjF+34RqDT+zg==\n-----END PRIVATE KEY-----\n'

serverCert = ssl.PrivateCertificate.loadPEM(cert + key)
server_factory = TLSMemoryBIOFactory(serverCert.options(), False, Factory.forProtocol(DummyServerProtocol))

options = ssl.optionsForClientTLS(u'localhost', ssl.Certificate.loadPEM(cert))
client_factory = TLSMemoryBIOFactory(options, True, Factory.forProtocol(DummyClientProtocol))


@defer.inlineCallbacks
def main(reactor):
    gc.collect()
    orig_colls = sum(gen['collections'] for gen in gc.get_stats())
    for _ in range(N // K):
        yield defer.gatherResults(
            loopbackAsync(
                TLSMemoryBIOProtocol(server_factory, DummyServerProtocol()),
                TLSMemoryBIOProtocol(client_factory, DummyClientProtocol())
            )
            for _ in range(K)
        )
    colls = sum(gen['collections'] for gen in gc.get_stats())
    print('collections', colls - orig_colls)
    print('mem', psutil.Process(os.getpid()).memory_info().rss//1024//1024, 'mb')


if len(sys.argv) >= 2 and sys.argv[1] == 'loose':
    gc.set_threshold(100000, 200, 100)
react(main)