Dieter Maurer wrote:
During our latest discussion to put my most important Zope2 products into a public repository, I have promissed to publish them on PyPI instead. Yesterday, I started work to fulfill this promiss and carefully read the PyPI related documentation -- to find out, that it is not easy to publish Zope2 products.
As the name suggests, PyPI is for Python packages. And Zope2 products rightfully are no Python packages:
When a Zope instance starts, it does potentially expensive things for its products.
I have tiny Zope instances with a few inexpensive products that start within a few seconds. And I have huge Zope instances with lots of products which parse huge XML files or have large message catalogs and take half to one minute to start.
Definitely, I do not want that all my Zope instances use the same products installed via "setuptools" somewhere under the central "site-packages".
My current ideas towards a solution:
We define a package prefix for Zope2 products, e.g. "zope2.products".
-1 to more magic namespaces!
Zope2 products are published to PyPI as "<prefix>.<productname>".
We already have that. Products.*. Basically, on Zope 2 trunk (and in 2.11), we've made Products/__init__.py declare Products.* as a namespace package. That means that you can package up an egg that uses this namespace package and upload it to the cheese shop. Several of the Plone packages, e.g. http://cheeseshop.python.org/pypi/Products.CMFDynamicViewFTI/3.0, do this.
We extend the Zope2 configuration with an option "additional-products" which lists the products used by the instance that are not at a standard place -- such as those installed by "setuptools"
I really don't see the need for this kind of complication. I would never install a Products.* package into the global python interpreter. That's a recipe for pain and incompatibility. Instead, I'd use zc.buildout or virtualenv to have a sandbox for these eggs. see http://plone.org/documentation/tutorial/buildout and http://martinaspeli.net/articles/python-package-management. Secondly, we already have something like additional-products, in that for packages outside the Products.* namespace, we do not automatically read ZCML, call initialize() and so on. Instead, we require that: - the package's ZCML is explicitly pulled in, either via a ZCML slug, or via an include from another ZCML file which is explicitly (or implicitly, if it's in Products/*) parsed. - the package uses the <five:registerPackage /> directive to declare the package a Zope 2 product, which causes its initialize() function to be called at the appropriate time. Note that anything in Products.*, whether eggs in that namespace package or plain directories in e.g. $INSTANCE_HOME/Products, behave as they always have: ZCML is auto-loaded by Five, initialize() is always called. Martin -- Acquisition is a jealous mistress