On Apr 22, 2007, at 10:32 AM, David Pratt wrote:
In looking at the way I am developing, my goals are package reuse
and thin glue in an app package (that is also the app egg) to bind
packages to make an application consisting mostly of installation,
security, testing and perhaps skinning. That said, I do not really
want or care about organizing packages neatly under a single src
folder to pull them together into a larger egg. To keep it simple,
I just want to list the eggs I use in app part of my buildout.
I wonder what you are trying to contrast here. Your goal of being
able to just list eggs sounds reasonable. Who would disagree with it?
You are penalized for this approach in app buildouts since more
small independent eggs (holding some generic functionality) with
their own dependencies equals more checks.
What checks are you referring to?
Being explicit like this
Like what? I don't understand what the "this" is that you are
increases the amount of time for the buildout to run, particularly
if there are plenty of eggs with many dependencies. Think in
numbers like 150 - 200+ eggs with zope and zope app - no exaggeration.
Are you referring to Buildout's checking for new egg versions?
Judicious use of the -N option can cut down on this a lot.
An approach that that leads to shorter app buildouts is to group
packages under the main app setup.py. This is currently what fits
with the development approach spelled out in the app recipe docs
but it has downsides also.
I don't understand what you are referring to. Which app recipe are
you referring to?
This is nice for speed in running a buildout but don't like the
fact that the main setup has got to capture dependencies for the
collection as a whole because you just a bigger egg with multiple
packages where you still need to track down dependencies. True,
some of these may be packages from external eggs you need to list,
but probably more are packages that you have assembled within your
app (that may be desirable to re-use) but where you have not been
being explicit about the dependencies (since these are determined
in an egg not a package).
Could you give some examples of what you're talking about. I'm
trying to follow you but can't. You seem to be discussing whether
dependencies should be listed in a setup file and suggesting that it
somehow affects buildout performance. buildout performance isn't
affected by *where* dependencies are defined. If your package has
dependencies, then list them. This is othogonal to performance.
Personally, I don't want to take the time to try to pull the
dependencies together in an app that is a collection of packages
like this - since it is a chore not worthy of a human.A machine can
do this better than I can (and it is welcome to the task!). Also,
apps are prone to change - each change equals more time re-
examining this over this again and again amidst a constantly
changing landscape of package revisions - yuk.
Are you referring to Python dependencies or ZCML dependencies?
If you are the author of a package, you should know what other
packages you're using. You should know when this changes. In
theory, determining these dependencies could be automated. No one
has automated it yet.
When you add that as a zope3/python developer you are mostly
working at a package level, you realize that spelling dependencies
with more granularity in an egg is much more attractive and just
easier overall than figuring this out for an app with a cluster of
packages afterwards (on top of how this all goes together with
other external/namespace packages like zope, zope.app, z3c, zc etc,
I wish I knew what you were trying to say here.
Are you saying that if A depends on B and B depends on C and A
doesn't use C directly that A should not have to list C as a
dependency? If so, I don't think anyone would disagree with you.
I feel the same way about the site.zcml. In the initial docs on the
What app recipe. Please be specific.
a smaller site.zcml is recommended since you can tuck most of the
meat in your app configuration. In experimenting, the bottom line
is it doesn't really matter where it is - because is really the
same size regardless of where the pieces reside. So I have been
considering - what am I really trying to do here - and how much
grief do I want to encumber putting it all together. The semantics
of having a large site.zcml that takes care of app configuration is
not inconsistent with the fact that I am using the buildout to
configure and build my app. So in the end I would be happy to
consider a larger site.zcml that does the work of organizing
includes to all packages in the app. And at the package level being
left with just making the includes within it (such as including a
browser or an ftest sub package) to complete the configuration tree.
Are you saying that If A depends on B and B depends on C that you
expect A to only have to include B's ZCML and rely on B's ZCML to
include C's ZCML? I think that's a reasonable strategy.
(It would be more reasonable if we filed some holes in ZCML
overriding, but that's a different topic.)
That said, I don't relish to time it will take to looking at
ordering all of the includes in a site.zcml.
You shouldn't have to.
Overall, it should not matter really as far as I can see. If egg1
needs the contents of egg2, it stands to reason that that package
includes of egg2 need to be pushed higher in the site.zcml that
those of egg1. Further if we adhere to good information in the egg
we should not have to worry that imports of packages in eggs will
not work. So I tend to believe that some means of scoring,
weighting or boosting could be used together with the exploration
of each egg for a configuration (*-configure.zcml, *-meta.zcml) to
autogenerate the site.zcml as the buildout proceeds.
I don't think this is necessary. An egg that has ZCML should load
the ZCML from other eggs it depends on. This means that these eggs
have to be designed this way.
Jim Fulton mailto:[EMAIL PROTECTED] Python
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