A quick glimpse at Distutils2 alpha3 – part 2

by Tarek Ziadé

It seems that doing a little bit of teasing on the next release generates valuable feedback. So I’ll do more 🙂

In the next version we have this really useful module called depgraph (full doc). It creates a dependency graph to study installed distribution, but also to-be-installed distributions. This is the basis of any installer script but is also useful for users who want to know what’s installed.

Setuptools has a module called pkg_resources that would allow to create such a feature, but distutils2 used an enhanced version of the stdlib module pkgutil which now supports PEP 376 but also offers a compatibility mode to be able to browse packages that were installed by pre-PEP 376 installers like Pip or easy_install. The new pkgutil module lives in a _backport package in distutils2 but will be pushed back to the stdlib as soon as we reach a stable version for distutils2.  It will make pkg_resources obsolete for the part that let you iterate on installed projects and will provide more. (Note that pkg_resources contains much more features besides.)

But enough talking, try to build your depgraph yourself ! depgraph can be called as a script to generate dependency graphs in the stdout, or as .dot (graphviz) files.

Here’s a small demo:

# installing the latest tip
$ sudo easy_install http://bitbucket.org/tarek/distutils2/get/bdfaec90d665.gz
Downloading http://bitbucket.org/tarek/distutils2/get/bdfaec90d665.gz
Processing bdfaec90d665.gz

# what do we have installed ?
$ python -m distutils2.depgraph
Dependency graph:
 PasteDeploy 1.3.3
 virtualenv 1.4.9
 pyflakes 0.4.0
 Distutils2 1.0a3
 ropemode 0.1-rc2
   rope 0.9.3 [rope (>= 0.9.2)]

# let's create a dot file of the dependencies
# if a distribution don't have a dependency it's not added - so you don't get crazy graphs
$ python -m distutils2.depgraph -d
Dot file written at "depgraph.dot"

# let's create an image
$ dot -Tpng depgraph.dot > depgraph.png

Try it out and let us know how it worked for you !