[Twisted-Python] Blocking reactor.connectSSL()

Jean-Paul Calderone exarkun at divmod.com
Mon Nov 24 22:05:53 EST 2008

On Mon, 24 Nov 2008 17:19:59 -0700, asset <asset at impactdamage.com> wrote:
>Is there a workaround for reactor.connectSSL() blocking during the SSL handshake?

It only blocks while it is performing the calculations for the crypto.  It
does not block on I/O during the crypto.  Generally, this isn't a problem.
If you have a large number of handshakes happening all the time and you
have another CPU, then you might get better resource utilization if you
offload the handshake crypto to the other processor, but you might also
get a win by using SSL sessions to reduce the connection setup overhead.

>I dug around and found some indications that it could be a problem fixed in Python 2.6 and 3.0, but also that its something that is worked around in Twisted, but I havent been able to find any reference to the issue with Twisted specifically.

I'm not sure what indications these would have been.  There are no significant
changes in Twisted's SSL support for Python 2.6 and Python 3.0 is not supported
by Twisted.


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