Re: [gentoo-dev] Versioning of Python scripts
В Сбт, 19/12/2009 в 16:24 +0100, Arfrever Frehtes Taifersar Arahesis
пишет:
- Scripts of packages supporting only e.g. Python 2 can be executed
(without necessity
of using of e.g. python2 /usr/bin/${script}) after activating of e.g.
Python 3.
- Scripts of packages supporting multiple Python versions ignore active
Python version.
The best solution, which removes these 2 disadvantages and preserves the
advantage, seems
to be to rename Python scripts to include Python version [1] in filenames,
and create wrapper
scripts, which call appropriate target scripts [2].
But still additional wrapper scripts and increased number of scripts in
total is not really nice. What do you think about another solution:
Separate possible script's python API versions into database, e.g.
in /var/db/pyabi/${CATEGORY}/${PN}-${SLOT}. Create python wrapper only
for unmerged but still in use (found from pyabi db) python versions,
e.g. /usr/bin/python3.2 in case you've unmerged python, but scripts
still reference python3.2.
This way scripts that use python versions that are still in the tree
will work without any overhead, fewer scripts in /{usr,}bin and during
python merge/unmerge it is possible to warn user about scripts that use
unmerged python versions (and thus run with some overhead). I guess
still we can add some user defined variable to prefer some python
versions over another...
- Scripts of packages supporting multiple Python versions cannot be easily
(without
necessity of using of e.g. python3.1 /usr/bin/${script}) executed with
a Python
version different than active Python version.
If you develop on python then... write your own wrappers or
use /usr/bin/python and that's it! In case you are not I'm not sure why
such switching is useful. Could you elaborate?
--
Peter.
Re: [gentoo-dev] Versioning of Python scripts
2009-12-21 11:50:14 Brian Harring napisał(a):
On Sat, Dec 19, 2009 at 04:24:49PM +0100, Arfrever Frehtes Taifersar Arahesis
wrote:
Distutils/Setuptools/Distribute modify shebangs of installed Python
scripts, so that they
contain path of Python interpreter with version included (e.g.
#!/usr/bin/python3.2).
This behavior has both advantage and disadvantages:
- Scripts of packages supporting only e.g. Python 2 can be executed
(without necessity
of using of e.g. python2 /usr/bin/${script}) after activating of e.g.
Python 3.
- Scripts of packages supporting multiple Python versions ignore active
Python version.
- Scripts of packages supporting multiple Python versions cannot be
easily (without
necessity of using of e.g. python3.1 /usr/bin/${script}) executed
with a Python
version different than active Python version.
The best solution, which removes these 2 disadvantages and preserves the
advantage, seems
to be to rename Python scripts to include Python version [1] in filenames,
and create wrapper
scripts, which call appropriate target scripts [2]. Some files sometimes
try to execute
e.g. /usr/bin/python /usr/bin/${script}, so wrapper scripts must be
implemented in Python.
Wrapper scripts try to execute ${wrapper_script}-${PYTHON_ABI} files
(e.g. py.test will
execute py.test-3.1, when Python 3.1 is set as active Python version).
distutils.eclass will automatically rename some scripts [3] in
${D}usr/bin and call
the function, which generates wrapper scripts. In case somebody is
interested in reading of
source code of python_generate_wrapper_scripts() function and potential
suggesting of
improvements, I'm attaching this function and 2 example wrapper scripts.
I'm planning to
commit addition of this function in next week.
Not really a huge fan of the EPYTHON var... can you clarify it's real
world usage?
It simplifies development of ebuilds of packages having non-Distutils-based
build systems.
E.g. ebuilds of packages, which support only Python2, install some executables
or libraries
(e.g. /usr/lib/kvirc/4.0/modules/libkvipythoncore.so of net-irc/kvirc) linked
against
libpythonX.Y.so and don't install any Python modules, will be able to simply
call
'python_set_active_version 2', which will export EPYTHON variable with
appropriate value.
Ebuilds should never manually set EPYTHON variable.
I can see that causing all sorts of mayhem as it passes
it's way down through python scripts invoking other scripts-
specifically thinking of a py3k only script being forced to 3.1, then
invoking a py2k script.
EPYTHON variable should be respected only by scripts, which are used during
building, testing
or installation of other packages and need to be called with appropriate Python
version.
Examples: py.test, trial
distutils_src_install() will call python_generate_wrapper_scripts() (at least
by default)
without -E option.
Beyond that, please provide a way to *disable* this for a pkg.
OK.
--
Arfrever Frehtes Taifersar Arahesis
signature.asc
Description: This is a digitally signed message part.
Re: [gentoo-dev] Versioning of Python scripts
On Sat, Dec 19, 2009 at 04:24:49PM +0100, Arfrever Frehtes Taifersar Arahesis
wrote:
Distutils/Setuptools/Distribute modify shebangs of installed Python scripts,
so that they
contain path of Python interpreter with version included (e.g.
#!/usr/bin/python3.2).
This behavior has both advantage and disadvantages:
- Scripts of packages supporting only e.g. Python 2 can be executed
(without necessity
of using of e.g. python2 /usr/bin/${script}) after activating of e.g.
Python 3.
- Scripts of packages supporting multiple Python versions ignore active
Python version.
- Scripts of packages supporting multiple Python versions cannot be easily
(without
necessity of using of e.g. python3.1 /usr/bin/${script}) executed with
a Python
version different than active Python version.
The best solution, which removes these 2 disadvantages and preserves the
advantage, seems
to be to rename Python scripts to include Python version [1] in filenames,
and create wrapper
scripts, which call appropriate target scripts [2]. Some files sometimes try
to execute
e.g. /usr/bin/python /usr/bin/${script}, so wrapper scripts must be
implemented in Python.
Wrapper scripts try to execute ${wrapper_script}-${PYTHON_ABI} files (e.g.
py.test will
execute py.test-3.1, when Python 3.1 is set as active Python version).
distutils.eclass will automatically rename some scripts [3] in ${D}usr/bin
and call
the function, which generates wrapper scripts. In case somebody is interested
in reading of
source code of python_generate_wrapper_scripts() function and potential
suggesting of
improvements, I'm attaching this function and 2 example wrapper scripts. I'm
planning to
commit addition of this function in next week.
Not really a huge fan of the EPYTHON var... can you clarify it's real
world usage? I can see that causing all sorts of mayhem as it passes
it's way down through python scripts invoking other scripts-
specifically thinking of a py3k only script being forced to 3.1, then
invoking a py2k script.
Beyond that, please provide a way to *disable* this for a pkg. At
least for pkgcore, I've already been looking at ways to deal with
this and would rather solve it at the pkg level (since EPYTHON let
alone eselect may not exist for certain target deployments of
pkgcore itself).
Basically, no point in having wrapper scripts if the target already
can do it's own version of this, hence wanting a way to disable it in
the ebuild- that's just for the script mangling, library installing
for multiple python abis is a seperate thing.
Aside from that, punting on the re import might be nice primarily for
speed reasons (no it's not a huge import in cost, but this is an extra
~.025 per python script invoked, ignoring the ~.3 to ~.02 for eselect
dependant on cache status).
~harring
pgpO4dhZ5T5bd.pgp
Description: PGP signature
