Controlling which Python to use
-------------------------------
The following assumes that your $HOME/.buildout/default.cfg has
python2.3 and python2.4 sections that define Python 2.3 and Python 2.4
executables.
We can specify the python to use by specifying the name of a section
to read the Python executable from. The default is the section
defined by the python buildout option.
We have a link server:
>>> print get(link_server),
<html><body>
<a href="demo-0.1-py2.3.egg">demo-0.1-py2.3.egg</a><br>
<a href="demo-0.1-py2.4.egg">demo-0.1-py2.4.egg</a><br>
<a href="demo-0.2-py2.3.egg">demo-0.2-py2.3.egg</a><br>
<a href="demo-0.2-py2.4.egg">demo-0.2-py2.4.egg</a><br>
<a href="demo-0.3-py2.3.egg">demo-0.3-py2.3.egg</a><br>
<a href="demo-0.3-py2.4.egg">demo-0.3-py2.4.egg</a><br>
<a href="demoneeded-1.0-py2.3.egg">demoneeded-1.0-py2.3.egg</a><br>
<a href="demoneeded-1.0-py2.4.egg">demoneeded-1.0-py2.4.egg</a><br>
<a href="demoneeded-1.1-py2.3.egg">demoneeded-1.1-py2.3.egg</a><br>
<a href="demoneeded-1.1-py2.4.egg">demoneeded-1.1-py2.4.egg</a><br>
<a href="index/">index/</a><br>
<a href="other-1.0-py2.3.egg">other-1.0-py2.3.egg</a><br>
<a href="other-1.0-py2.4.egg">other-1.0-py2.4.egg</a><br>
</body></html>
We have a sample buildout. Let's update it's configuration file to
install the demo package using Python 2.3.
>>> write(sample_buildout, 'buildout.cfg',
... """
... [buildout]
... parts = demo
... eggs-directory = eggs
...
... [demo]
... recipe = zc.recipe.egg
... distribution = demo <0.3
... find-links = %(server)s
... index = %(server)s/index
... python = python2.3
... """ % dict(server=link_server))
In our default.cfg file in the .buildout subdirectiry of our
directory, we have something like::
[python2.3]
executable = /usr/bin/python
[python2.4]
executable = /usr/local/bin/python2.4
(Of course, the paths will vary from system to system.)
Now, if we run the buildout:
>>> import os
>>> os.chdir(sample_buildout)
>>> buildout = os.path.join(sample_buildout, 'bin', 'buildout')
>>> print system(buildout),
we'll get the Python 2.3 eggs for demo and demoneeded:
>>> ls(sample_buildout, 'eggs')
- demo-0.2-py2.3.egg
- demoneeded-1.1-py2.3.egg
And the generated scripts invoke Python 2.3:
>>> f = open(os.path.join(sample_buildout, 'bin', 'demo'))
>>> f.readline().strip() == '#!' + python2_3_executable
True
>>> print f.read(),
<BLANKLINE>
import sys
sys.path[0:0] = [
'/private/tmp/tmpOEtRO8sample-buildout/eggs/demo-0.2-py2.3.egg',
'/private/tmp/tmpOEtRO8sample-buildout/eggs/demoneeded-1.1-py2.3.egg'
]
<BLANKLINE>
import eggrecipedemo
<BLANKLINE>
if __name__ == '__main__':
eggrecipedemo.main()
>>> f = open(os.path.join(sample_buildout, 'bin', 'py_demo'))
>>> f.readline().strip() == '#!' + python2_3_executable
True
>>> print f.read(),
import sys
<BLANKLINE>
if len(sys.argv) == 1:
import os
# Restart with -i
os.execl(sys.executable, sys.executable, '-i', sys.argv[0], '')
<BLANKLINE>
sys.path[0:0] = [
'/tmp/tmpiIJY3Ysample-buildout/eggs/demo-0.2-py2.3.egg',
'/tmp/tmpiIJY3Ysample-buildout/eggs/demoneeded-1.1-py2.3.egg'
]
<BLANKLINE>
if len(sys.argv) > 1 and sys.argv[1:] != ['']:
sys.argv[:] = sys.argv[1:]
execfile(sys.argv[0])
If we change the Python version to 2.4, we'll use Python 2.4 eggs:
>>> write(sample_buildout, 'buildout.cfg',
... """
... [buildout]
... parts = demo
... eggs-directory = eggs
...
... [demo]
... recipe = zc.recipe.egg
... distribution = demo <0.3
... find-links = %(server)s
... index = %(server)s/index
... python = python2.4
... """ % dict(server=link_server))
>>> print system(buildout),
>>> ls(sample_buildout, 'eggs')
- demo-0.2-py2.3.egg
- demo-0.2-py2.4.egg
- demoneeded-1.1-py2.3.egg
- demoneeded-1.1-py2.4.egg
>>> f = open(os.path.join(sample_buildout, 'bin', 'demo'))
>>> f.readline().strip() == '#!' + python2_4_executable
True
>>> print f.read(),
<BLANKLINE>
import sys
sys.path[0:0] = [
'/private/tmp/tmpOEtRO8sample-buildout/eggs/demo-0.2-py2.4.egg',
'/private/tmp/tmpOEtRO8sample-buildout/eggs/demoneeded-1.1-py2.4.egg'
]
<BLANKLINE>
import eggrecipedemo
<BLANKLINE>
if __name__ == '__main__':
eggrecipedemo.main()
>>> f = open(os.path.join(sample_buildout, 'bin', 'py_demo'))
>>> f.readline().strip() == '#!' + python2_4_executable
True
>>> print f.read(),
import sys
<BLANKLINE>
if len(sys.argv) == 1:
import os
# Restart with -i
os.execl(sys.executable, sys.executable, '-i', sys.argv[0], '')
<BLANKLINE>
sys.path[0:0] = [
'/tmp/tmpiIJY3Ysample-buildout/eggs/demo-0.2-py2.4.egg',
'/tmp/tmpiIJY3Ysample-buildout/eggs/demoneeded-1.1-py2.4.egg'
]
<BLANKLINE>
if len(sys.argv) > 1 and sys.argv[1:] != ['']:
sys.argv[:] = sys.argv[1:]
execfile(sys.argv[0])