[Zope-dev] "Overriding Products"

[Martijn Jacobs]

Hello guys.

I have a question regarding  product importing in zope 2.7.x,  as since 
zope 2.7 this part is way more flexible then it was before. I'd like to 
accomplish the next situation :

-
A Zope base installation has Product X installed in /lib/python/Products 
which I want to change or develop further
-
x instances of Zope use the produtc from this base install.
-
At one instance I want to test and develop, without breaking the other 
instances.
-
Copying the Product X folder to the <instance_home>/Products folder is 
not an option, as import conflict errors occure if you do not remove the 
product from the base installation.
-
Copying a local version in all 4 instances is a solution, but to manage 
that will cost alot of work, especially if you have alot of instances.
-

What I really want is that you can copy the Product X folder to the 
Products (or "CustomProducts" for example) of an zope instance, and that 
zope will figure out itself that it should import that version of the 
product instead of the copy in the base installation. 'Overriding' base 
products is the name you could give this situation.

I tried alot myself, for example checking in the __init__.py if there is 
a copy of this product in <instance_home>/CustomProducts and then 
importing that product instead of my own, but I always get into trouble :

AttributeError: 'module' object has no attribute '<Classname>'

It doesn't have to work for all products, only for some of the products 
that we are developing ourselfs. We also have a different structure than 
normal products as following :
Main Product   - Sub product X
               - Sub product Y

In the __init__.py of Main product we import and initialize the 
subproducts. The idea is to put one of those subproducts in a zope 
instance/CustomProducts folder for further development and that the 
other instances of zope still uses the base version of the subproduct.

I hope you can help, thanks in advance for your time.

Kind regards,

-- 
Martijn Jacobs
East Site | Postbus 642 | 6800 AP Arnhem
t: +31 (0) 26 35 14 295 | f: +31 (0) 26 44 20 432
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