[ZODB-Dev] ZODB.config and py2exe

[Michael Bernstein]

Hi Folks,

I realize that this is a bit off-topic for this list, but there doesn't 
seem to be a more-appropriate list, and I figure you might be interested 
in this rather strange bug.

To cut a long story short, I have a simple ZODB-based CLI app that I was 
trying to package up with py2exe for distribution. The app itself is 
hardly more than a vehicle for me to experiment with various things, so 
I'll spare you the specifics.

Suffice it to say that use of ZODB.config causes the .exe to crash on 
startup.

My environment is Python 2.3.4 on Windows 2000, ZODB 3.2, and py2exe 0.5.

Here is the relevant python code:

==============================
import ZODB.config

db = ZODB.config.databaseFromURL('bookdb.conf')
conn = db.open()
dbroot = conn.root()
==============================

And the traceback:

Traceback (most recent call last):
   File "bookcap.py", line 20, in ?
   File "ZODB\config.pyc", line 51, in databaseFromURL
   File "ZODB\config.pyc", line 34, in getDbSchema
   File "ZConfig\loader.pyc", line 36, in loadSchema
   File "ZConfig\loader.pyc", line 68, in loadURL
   File "ZConfig\loader.pyc", line 100, in openResource
ZConfig.ConfigurationError: error opening resource C:\Documents and 
Settings\Michael 
Bernstein\Desktop\BookCapCLI\dist\library.zip\ZODB\config.xml: <urlopen 
error unknown url type: c>

Examining the created library.zip file finds that the config.xml file 
from the ZODB package was not included.

I tried to find a py2exe option to force the inclusion of the file, but 
AFAICT you can only specify modules or packages for inclusion in 
library.zip, not arbitrary files within packages.

In the end, the fix for me was fairly simple, I just avoided using a 
bookdb.conf config file, and hard coded the ZODB setup:

==============================
from ZODB import FileStorage, DB

storage = FileStorage.FileStorage('bookcap.fs')
db = DB(storage)
conn = db.open()
dbroot = conn.root()
==============================

...which works perfectly well in both the original and .exe versions of 
the app.

This is hardly a major inconvenience for a small app such as mine, but 
as I grow it, not having the ability to use declarative configuration 
files could become annoying, and so I thought I would mention it here in 
case this interaction between py2exe and ZODB is not a known issue.

Cheers,

-- 
- Michael R. Bernstein  |  Author of Zope Bible
   michaelbernstein.com  |  & Zope.org Webmaster
      panhedron.com      |    PythonPhotos.org