[PEAK] setuptools dependencies installed from os packages
Phillip J. Eby
pje at telecommunity.com
Mon Dec 19 13:11:05 EST 2005
At 07:11 PM 12/19/2005 +0200, alexander smishlajev wrote:
>it would be very nice if setuptools could find required modules installed
>with os package management system (binary packages on windows, redhat and
>debian, ports on *bsd, ebuilds on gentoo...)
>perhaps there could be a standard way for setuptools-aware package to
>declare it's installed version?
>the long story: i am trying to run SQLObject tests. SQLObject test system
>verifies dependency requirements. one of the requirements is
>"FormEncode>=0.2.2". i have FormEncode-0.4 installed from windows
>installer. but SQLObject tests fail with error
>now i have two options: remove installed FormEncode and reinstall it from
>egg, or hack SQLObject.egg-info and remove requirement for FormEncode. i
>don't like the first option because setuptools don't provide a way (other
>than manual file removal) to uninstall obsolete packages, and i don't like
>the second option because it smells very bad.
>... any thoughts?
The current version of setuptools in SVN allows you to make a bdist_wininst
of an egg.
So, if you use these commands:
easy_install -eb. FormEncode
you will have a FormEncode .exe that can uninstall itself, but which is
nonetheless a valid egg. The .exe will not use a .pth, and the files will
be installed unzipped in a "traditional" package layout, but there will
also be an .egg-info directory installed to site-packages that will tell
other packages that it is installed.
If you need to do this with a package that does not use setuptools, you can
easy_install -eb. SomePackage
python -c "import setuptools; execfile('setup.py')" bdist_wininst
which will force the use of setuptools to build a bdist_wininst egg.
The "bdist_rpm" command is also supported for this, and the third-party
"bdist_nsi" (NSIS installer) and "bdist_msi" (Microsoft installer) commands
should probably work also.
If you want to create packages for some other system, you can use "install
--single-version-externally-managed" along with --root and/or --record to
prebuild an installation for packaging. If you are using something like
bdist_deb that uses "setup.py install" you will need to modify the tool to
include the --single-version-externally-managed option. And if the package
does not use setuptools, you will need the "python -c" hack shown above in
order to force the setup script to use setuptools.
To sum up: you can build system packages for eggs now, and you can build
system packages wrapping eggs even for packages that do not currently use
setuptools. But there is not a way to detect the presence and version of
arbitrary system packages on arbitary platforms.
If you wish to flag the presence of such packages, however, you can now add
.egg-info files to the directory on sys.path where they are installed. The
.egg-info file should be named with the project name and version (e.g.
FormEncode-0.4.egg-info) and its contents should be the distutils PKG-INFO
file found in the project's source distribution. The above-described
packaging techniques do this automatically, although they use an .egg-info
To use any of these features, you must have the latest setuptools, i.e. one
less than 48 hours old or so (these features were added late last
week). To upgrade, run:
or if you prefer to wrap setuptools itself in a bdist_wininst wrapper, do:
ez_setup.py -eb. setuptools==dev
and then install the resulting .exe.
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