[Twisted-Python] buildProtocol never called

travis+ml-twisted at subspacefield.org travis+ml-twisted at subspacefield.org
Sat Jul 4 20:08:42 EDT 2009

On Sat, May 30, 2009 at 06:17:54PM -0500, travis+ml-twisted at subspacefield.org wrote:
> The problem I'm having is this; I upgraded my firewall from OpenBSD
> 4.2 or so to OpenBSD 4.5, and now I'm working with newer versions of
> all the software including Twisted.
> The program works fine normally, and can run in the background, but if I
> invoke a daemonize() routine that turns it into a network daemon, it
> refuses to serve incoming TCP connections.  Actually the TCP connection
> is made, but the software never responds to it.
> Specifically, my twisted.internet.protocol.Factory instance is created,
> but buildProtocol is never called.
> Before I dive deeply into debugging the software, I thought I'd ask if
> anyone knew off the top of their head any reason why Twisted might not
> act the same if it was daemonized (no controlling terminal, no
> stdin/out/err, forked as a background process).

I ran ktrace/kdump against the binary and it appears that python likes to
open file handles to the script and certain modules for file descriptors
5-7 or so (depending on how much you import), and if you close those file
descriptors, unusual things happen when python tries to access them.

In the end I decided it was not important enough to close all the parent's
file descriptors, and it runs fine as a deamon leaving them open.
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