Python discussion: Difference between revisions

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{{Outdated|also, this article describes discussions from old days}}
== python basics ==
== python basics ==
* '''*.pth''' files
* '''*.pth''' files
:Python supports *.pth files which contain the paths to the parent directories of your python modules one per line. Those files are placed in site-packages and are typically generated by python package managers such as easy_install.
:Python supports *.pth files which contain the paths to the parent directories of your python modules one per line. Those files are placed in site-packages and are typically generated by python package managers such as easy_install.
* PYTHONPATH
* PYTHONPATH
:The other way is to set additional paths for the required modules before running python. This is done by setting the python paths in the environment variable PYTHONPATH. A path typcially looks like this on a Nix system: /nix/store/fxpfc2hyw5qbxly8xwrxzai8lny4pcq2-ipython-0.11/lib/python2.7/site-packages/ipython-0.11-py2.7.egg
:The other way is to set additional paths for the required modules before running python. This is done by setting the python paths in the environment variable PYTHONPATH. A path typically looks like this on a Nix system: /nix/store/fxpfc2hyw5qbxly8xwrxzai8lny4pcq2-ipython-0.11/lib/python2.7/site-packages/ipython-0.11-py2.7.egg
* PYTHONUSERBASE
* PYTHONUSERBASE
:?
:?
Line 22: Line 23:


=== packaging virt-manager ===
=== packaging virt-manager ===
see '''problem 2''' in [http://permalink.gmane.org/gmane.linux.distributions.nixos/8732]
see '''problem 2''' in [https://web.archive.org/web/20150406220317/https://permalink.gmane.org/gmane.linux.distributions.nixos/8732]


=== python-gudev ===
=== python-gudev ===
i have problems packaging python-gudev:
i have problems packaging python-gudev:
  gudevmodule.c:19:23: fatal error: pygobject.h: No such file or directory
gudevmodule.c:19:23: fatal error: pygobject.h: No such file or directory
 
but looking at the exports (nix-env -i python-gudev -K; source env-vars) i can see:
but looking at the exports (nix-env -i python-gudev -K; source env-vars) i can see:
  -I/nix/store/lqsihhkhl7rhr18x7qiviihyp2byc5gw-pygobject-2.27.0/include
  -I/nix/store/lqsihhkhl7rhr18x7qiviihyp2byc5gw-pygobject-2.27.0/include


but in that folder there is only pygtk-2.0 folder:
but in that folder there is only pygtk-2.0 folder:
  ls -la /nix/store/lqsihhkhl7rhr18x7qiviihyp2byc5gw-pygobject-2.27.0/include
ls -la /nix/store/lqsihhkhl7rhr18x7qiviihyp2byc5gw-pygobject-2.27.0/include
  pygtk-2.0/
pygtk-2.0/


so in that folder i find:
so in that folder i find:
  ls -la /nix/store/lqsihhkhl7rhr18x7qiviihyp2byc5gw-pygobject-2.27.0/include/pygtk-2.0/
ls -la /nix/store/lqsihhkhl7rhr18x7qiviihyp2byc5gw-pygobject-2.27.0/include/pygtk-2.0/
  pyglib.h  pygobject.h
pyglib.h  pygobject.h


=== the problem ===
=== the problem ===
as discussed in [http://old.nabble.com/Python-3-to22076291.html#a22119842] and quoting [https://nixos.org/repos/nix/nixpkgs/trunk/pkgs/development/python-modules/pygobject/default.nix]
as discussed in [http://old.nabble.com/Python-3-to22076291.html#a22119842] and quoting [https://nixos.org/repos/nix/nixpkgs/trunk/pkgs/development/python-modules/pygobject/default.nix]
    # All python code is installed into a "gtk-2.0" sub-directory. That
# All python code is installed into a "gtk-2.0" sub-directory. That
    # sub-directory may be useful on systems which share several library
# sub-directory may be useful on systems which share several library
    # versions in the same prefix, i.e. /usr/local, but on Nix that directory
# versions in the same prefix, i.e. /usr/local, but on Nix that directory
    # is useless. Furthermore, its existence makes it very hard to guess a
# is useless. Furthermore, its existence makes it very hard to guess a
    # proper $PYTHONPATH that allows "import gtk" to succeed.
# proper $PYTHONPATH that allows "import gtk" to succeed.


so how should i package python-gudev then? the source for python-gudev (which produces the above error) can be found at [https://github.com/NixOS/nixpkgs/blob/master/pkgs/development/python-modules/python-gudev/default.nix]
so how should i package python-gudev then? the source for python-gudev (which produces the above error) can be found at [https://github.com/NixOS/nixpkgs/blob/master/pkgs/development/python-modules/python-gudev/default.nix]
== links ==
* http://dpaste.com/756606/
* https://gitorious.org/goibhniu/pages/nix-python (to be merged with this page)

Latest revision as of 04:01, 14 September 2024

python basics

  • *.pth files
Python supports *.pth files which contain the paths to the parent directories of your python modules one per line. Those files are placed in site-packages and are typically generated by python package managers such as easy_install.
  • PYTHONPATH
The other way is to set additional paths for the required modules before running python. This is done by setting the python paths in the environment variable PYTHONPATH. A path typically looks like this on a Nix system: /nix/store/fxpfc2hyw5qbxly8xwrxzai8lny4pcq2-ipython-0.11/lib/python2.7/site-packages/ipython-0.11-py2.7.egg
  • PYTHONUSERBASE
?

in general see [1]

general python integration into nixos

requirements

  • mix python 2.x and 3.x in the same profile
marcweber and qknight vote against that. it makes packaging complicated: to mix python2 and python3? We could introduce NIX_PYTHON_SITES_2 and NIX_PYTHON_SITES_3 or such. a better way is to use load-env-whatever (see [2] )
  • pyLibA (python wrapper for a library) is used by pyLibB: nix expressions must be able to use either

proposed nixos environment variables

  • NIX_PYTHON_SITES

qknight's problems

packaging virt-manager

see problem 2 in [3]

python-gudev

i have problems packaging python-gudev:

gudevmodule.c:19:23: fatal error: pygobject.h: No such file or directory

but looking at the exports (nix-env -i python-gudev -K; source env-vars) i can see:

-I/nix/store/lqsihhkhl7rhr18x7qiviihyp2byc5gw-pygobject-2.27.0/include

but in that folder there is only pygtk-2.0 folder:

ls -la /nix/store/lqsihhkhl7rhr18x7qiviihyp2byc5gw-pygobject-2.27.0/include
pygtk-2.0/

so in that folder i find:

ls -la /nix/store/lqsihhkhl7rhr18x7qiviihyp2byc5gw-pygobject-2.27.0/include/pygtk-2.0/
pyglib.h  pygobject.h

the problem

as discussed in [4] and quoting [5]

# All python code is installed into a "gtk-2.0" sub-directory. That
# sub-directory may be useful on systems which share several library
# versions in the same prefix, i.e. /usr/local, but on Nix that directory
# is useless. Furthermore, its existence makes it very hard to guess a
# proper $PYTHONPATH that allows "import gtk" to succeed.

so how should i package python-gudev then? the source for python-gudev (which produces the above error) can be found at [6]