Phillip J. Eby wrote: > I wanted to get this in before the Py3K PEP deadline, since this is a > Python 2.6 PEP that would presumably impact 3.x as well. Feedback welcome. > > > PEP: 365 > Title: Adding the pkg_resources module > Version: $Revision: 55032 $ > Last-Modified: $Date: 2007-04-30 20:24:48 -0400 (Mon, 30 Apr 2007) $ > Author: Phillip J. Eby <[EMAIL PROTECTED]> > Status: Draft > Type: Standards Track > Content-Type: text/x-rst > Created: 30-Apr-2007 > Post-History: 30-Apr-2007 > > > Abstract > ======== > > This PEP proposes adding an enhanced version of the ``pkg_resources`` > module to the standard library. > > ``pkg_resources`` is a module used to find and manage Python > package/version dependencies and access bundled files and resources, > including those inside of zipped ``.egg`` files. Currently, > ``pkg_resources`` is only available through installing the entire > ``setuptools`` distribution, but it does not depend on any other part > of setuptools; in effect, it comprises the entire runtime support > library for Python Eggs, and is independently useful. > > In addition, with one feature addition, this module could support > easy bootstrap installation of several Python package management > tools, including ``setuptools``, ``workingenv``, and ``zc.buildout``. > > > Proposal > ======== > > Rather than proposing to include ``setuptools`` in the standard > library, this PEP proposes only that ``pkg_resources`` be added to the > standard library for Python 2.6 and 3.0. ``pkg_resources`` is > considerably more stable than the rest of setuptools, with virtually > no new features being added in the last 12 months. > > However, this PEP also proposes that a new feature be added to > ``pkg_resources``, before being added to the stdlib. Specifically, it > should be possible to do something like:: > > python -m pkg_resources SomePackage==1.2 > > to request downloading and installation of ``SomePackage`` from PyPI. > This feature would *not* be a replacement for ``easy_install``; > instead, it would rely on ``SomePackage`` having pure-Python ``.egg`` > files listed for download via the PyPI XML-RPC API, and the eggs would > be placed in the ``$PYTHONEGGS`` cache, where they would **not** be > importable by default. (And no scripts would be installed) However, > if the download egg contains installation bootstrap code, it will be > given a chance to run. > > These restrictions would allow the code to be extremely simple, yet > still powerful enough to support users downloading package management > tools such as ``setuptools``, ``workingenv`` and ``zc.buildout``, > simply by supplying the tool's name on the command line. > > > Rationale > ========= > > Many users have requested that ``setuptools`` be included in the > standard library, to save users needing to go through the awkward > process of bootstrapping it. However, most of the bootstrapping > complexity comes from the fact that setuptools-installed code cannot > use the ``pkg_resources`` runtime module unless setuptools is already > installed. Thus, installing setuptools requires (in a sense) that > setuptools already be installed. > > Other Python package management tools, such as ``workingenv`` and > ``zc.buildout``, have similar bootstrapping issues, since they both > make use of setuptools, but also want to provide users with something > approaching a "one-step install". The complexity of creating bootstrap > utilities for these and any other such tools that arise in future, is > greatly reduced if ``pkg_resources`` is already present, and is also > able to download pre-packaged eggs from PyPI. > > (It would also mean that setuptools would not need to be installed > in order to simply *use* eggs, as opposed to building them.) > > Finally, in addition to providing access to eggs built via setuptools > or other packaging tools, it should be noted that since Python 2.5, > the distutils install package metadata (aka ``PKG-INFO``) files that > can be read by ``pkg_resources`` to identify what distributions are > already on ``sys.path``. In environments where Python packages are > installed using system package tools (like RPM), the ``pkg_resources`` > module provides an API for detecting what versions of what packages > are installed, even if those packages were installed via the distutils > instead of setuptools. > > > Implementation and Documentation > ================================ > > The ``pkg_resources`` implementation is maintained in the Python > SVN repository under ``/sandbox/trunk/setuptools/``; see > ``pkg_resources.py`` and ``pkg_resources.txt``. Documentation for the > egg format(s) supported by ``pkg_resources`` can be found in > ``doc/formats.txt``. HTML versions of these documents are available > at: > > * http://peak.telecommunity.com/DevCenter/PkgResources and > > * http://peak.telecommunity.com/DevCenter/EggFormats > > (These HTML versions are for setuptools 0.6; they may not reflect all > of the changes found in the Subversion trunk's ``.txt`` versions.) > > > Copyright > ========= > > This document has been placed in the public domain.
I'm really surprised that there hasn't been more comment on this. -- Talin _______________________________________________ Python-Dev mailing list Python-Dev@python.org http://mail.python.org/mailman/listinfo/python-dev Unsubscribe: http://mail.python.org/mailman/options/python-dev/archive%40mail-archive.com
