RE: [Zope-dev] Problem with starting thread in the initialization of a product ( Linux)

22 Aug 2001


      Thanks, Steve, it worked! I ran the zope as myself with port 8080. But in
the real case, we'll run it as root with port 80. So I'll try to hack z2.py
and see if I'm of good luck. Thanks again.

Lily Li
...
-----Original Message-----
From: Steve Alexander [mailto:steve@cat-box.net]
Sent: Wednesday, August 22, 2001 4:20 PM
To: Lily Li
Cc: 'zope-dev@zope.org'
Subject: Re: [Zope-dev] Problem with starting thread in the
initialization of a product ( Linux)
Lily Li wrote:
...
Hi friends,
I've encountered a serious problem when trying to port my 
product from win32
system to Linux.
As we need several threads running as long as zope is up 
running, we started
the thread (tried both daemon one and non-daemon one) in 
the initialization
of the product like (in __init__.py):
import threading
def initialize(context):
                 .........
                 .........
                  t = threading.Thread()
                  t.setDaemon(1)
                  t.start()
Then zope will stop responding to any HTTP request. If the 
thread is not
started, the zope will run correctly. Does anyone has the 
similar experience
with it? It seems that the problem is caused by starting thread when
initializing. I did threading thing before but started by 
HTTP request and
it worked fine. Besides, this code works fine on win32 systems.
If anyone could give me any help as soon as possible, it's highly
appreciated.
Let me guess:
You've installed Zope as root.
The problem is that Zope changes uid and gid after initializing the 
products. There's a bug/misfeature with Linux in that when a process 
changes uid/gid, any existing threads do not change with it.
If you look up the list archives for problems with Xron, you'll see 
reports of similar problems.
The solutions are to do one of the following:
* If you don't need Zope to access port 80, or any privilaged 
port, run 
Zope as a non-root user.
* Modify Zope to change uid/gid before initializing products.
* Modify Zope to notify products with a call-back after it 
has changed 
uid/gid, so that products can do things like launch threads.
* Modify Linux to fix the problem.
--
Steve Alexander
Software Engineer
Cat-Box limited