[Zope-dev] Re: ploneout - Or how using zc.buildout for a common
Zope2 project might look like
optilude at gmx.net
Thu Jan 25 19:52:54 EST 2007
Rob Miller wrote:
> honestly, it seems to me that buildout tries to do too much. it's trying to
> handle both repeatable deployment recipes AND providing a sandbox within which
> to run things. there may not be a point to having an extra layer on top of
> buildout, but buildout sure does seem to me a bit heavy if all i want is a
> sandbox. so now i have to learn the workingenv way if i just need a sandbox,
> but i have to learn the buildout way if i also want repeatable deployments?
Potentially. But I find it kind of reassuring to have a well-defined
list of which eggs are part of my "special" environment i.e. the one
tied to my instance.
>> As said already, I think once you've got buildout, there's no need for
>> workingen, except if you think that "Zope stinks" ;)
> this is shortsighted, IMO. i know zope quite well, but i bounced off of
> buildout b/c it required too much knowledge to even get started. i think it's
> much more likely that people from the greater python community will pick up
> and start using workingenv than they will zc.buildout.
Again, I think the two are orthogonal.
And honestly, I found zc.buildout pretty easy to understand. I resisted
it for a while, it seems liked it *should* be complex, and I won't
pretend to understand how it manages eggs in any detail, but I don't
think it matters.
Look at http://dev.plone.org/plone/browser/ploneout/trunk/buildout.cfg -
I find that pretty self-explanatory. I tried to document how it works at
a high level and how you may use it here
And writing a new recipe is as simple as this:
All that is plain python code, the only thing you need to understand
about buildout is that it has a dict-like object called 'options' which
reflects the options in the current part's section in buildout.cfg, and
a higher level dict-like object called 'buildout' which has the options
for all the parts (so buildout['foo'] are the options for part [foo] in
buidout.cfg). Each part is associated with a recipie. Recipies are ordered.
> personally, i like chris mcdonough's approach with his buildit package. it
> does two things:
> - it retrieves files from anywhere on the 'net (cvs, svn, tarball, whatever)
> and puts them where you want them on your target machine(s)
You can do that quite easily with buildout as well. I would like to make
a more generic recipe for retrieving tarballs for e.g. zope
installation, and I think it'd be as hard as figuring out which python
function to use to download something.
> - it launches external scripts that then perform whatever final configuration
> you may want to perform.
Again, if you want a recipe to do that, it's trivial to write (10 lines
of code?). Instead of an external script, though, I would probably find
it easier to write that as a buildout recipe in python.
> buildit is also recipe driven, and it's smart enough to pick up where it left
> off on a previous run, a'la make. i'd guess that you could use buildit and
> workingenv to accomplish pretty much everything you can do w/ zc.buildout, and
> you wouldn't have to bend your brain so much to do so.
I'm just struggling to see why it's so hard to figure out how buildout
works. Perhaps it just fits my brain. But honestly, once Hanno showed me
his initial steps with ploneout and I'd taken ten minutes with pdb
inside the __init__() and install() functions (the only two...) in his
recipe the pieces fitted together in my head almost instantly.
I don't greatly care how the standard zc.recipe.egg mechanism installs
eggs because it works and because I can see clearly where they come
from, how I create new ones and I'm satisfied that they are available ot
my python interpreter. If I did care, I'm sure I wouldn't find it that
hard to trace, though.
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