What's the buildout:zcml option for?

Question

In one of my projects' buildout.cfg files I have something like this:

[buildout]
...
zcml =
    my.package
    plone.reload
...

Everything works fine but I'm still puzzled about what's the reason some packages do need to be listed here and why others don't.

What's the purpose of it to begin with?

While doing some research I end up on https://pypi.python.org/pypi/munin.zope/2.1 which says that if you use z3c.autoinclude and plone (+3.3) you don't need it.

Does that mean that if a distribution has the z3c.autoinclude slug on its setup.py, i.e.

entry_points="""
# -*- Entry points: -*-
[z3c.autoinclude.plugin]
target = plone
""",

you don't have to care about buildout:zcml?

Exactly, All packages you're using should have the `z3c.autoinclude slug`, so loading the zcml manually is not necessary. btw: I never defined `zcml` in buildout part like eggs. — Mathias, May 21 '15 at 05:33
BTW, the autoinclusion saves time at first hand, but there's also critical voices around, pointing out that "Explicit is better than implicit". See G. Chapelle: http://bubblenet.be/blog/lets-get-rid-of-z3c.autoinclude and D. J. Beitey:http://davidjb.com/blog/2010/07/plone-overrides-zcml-gets-auto-included-with-z3c-autoinclude/ — Ida, May 29 '15 at 08:19

aclark · Accepted Answer · 2015-05-27T21:25:20.253

5

There is no inherent functionality related to the zcml parameter in the [buildout] section, other than a convenient place to define zcml.

Typically an [instance] section will refer to it:

[instance]
recipe = plone.recipe.zope2instance
eggs = Plone
zcml = ${buildout:zcml}

edited May 27 '15 at 21:25

answered May 21 '15 at 02:39

aclark

score 1 · Answer 2 · answered Jun 07 '15 at 22:02

In buildout config files, name=value can be used in two ways:

buildout:zcml is an example of the second case.

In other words, the only reason to use buildout:zcml would be the need to use its value in various places.

However, when I need to reuse zcml, I rather define it in a plone.recipe.zope2instance part. And reuse that value in another part.

2 Answers2