[Zope] Integrating Zope with Excel.

[Paul Winkler]

On Wed, Sep 01, 2004 at 10:17:34AM +0100, Chris Withers wrote:
> Paul Winkler wrote:
> 
> >1) an External Method was making an http request using httplib
> >to a host that had become (wrongly) firewalled.
> >I don't know how this could completely block zope, but that
> >was the behavior I observed. A bit of using gcc as described
> >in the "Debug a Spinning Zope" article helped me identify
> >the ext. method in question and rewrite it so it can't
> >possibly block like that.
> 
> This sounds like something that should be discussed on zope-dev, but if 
> it comes down to something C-ish blocking python's thread stuff, then ti 
> may even end up on python-dev...

I don't think it's really a problem anymore:

I was using either urllib or urllib2 (don't remember).
At that time (python 2.1), socket.setdefaulttimeout() did not
exist so any request to a socket could potentially spin forever.

My theory is that, each time a request came for my 
external method, the current worker thread was then
waiting forever for a reply from the firewalled socket.
So, inevitably, sooner or later all threads were doing this
and the server was effectively hung.

But, I haven't been able to reproduce this behavior today with Zope 2.7.2,
even with socket.setdefaulttimeout(None).
I've currently got 16 pending requests for the never-finishing
external method, and I can still browse zope just fine.

-- 

Paul Winkler
http://www.slinkp.com