I’ve just spent too much time figuring this out. I’ve had to piece it together from many other sites.
I need to set up Trac .12 on CentOS 5, but want to do that without interfering with the current setup of Trac and Subversion on the system.
So in comes virtualenv. This allows you to create a virtual environment for python. Like a separate install. The beauty is, once this is set up you can install different versions of python packages (like Trac and Subversion) that don’t have to interact with each other.
To install virtualenv was pretty simple. With root permissions do
easy_install virtualenv
Now, as your normal user, you can install a virtual environment.
virtualenv --no-site-packages foo
This will create a new folder called foo with a virtual environment for python. It won’t reference any of the other installed python packages (like the old Trac version).
Now upgrade the Genshi package with
easy_install --upgrade Genshi
Then, to install Trac do
easy_install Trac==0.12
That’s the part that always hung me up. I would just do easy_install Trac which would cough up this ugly error:
Searching for trac
Reading http://pypi.python.org/simple/trac/
Reading http://trac.edgewall.org/
Reading http://trac.edgewall.org/wiki/TracDownload
Reading http://trac.edgewall.com/
Reading http://projects.edgewall.com/trac
Reading http://projects.edgewall.com/trac/wiki/TracDownload
Best match: Trac 0.12.2
Downloading ftp://ftp.edgewall.com/pub/trac/Trac-0.12.2.zip
Processing Trac-0.12.2.zip
Running setup.py -q bdist_egg --dist-dir trac-dir/trac/egg-dist-tmp-JmdQXW
Traceback (most recent call last):
File "/home/ammon/foo/bin/easy_install", line 7, in ?
sys.exit(
File "/home/ammon/foo/lib/python2.4/site-packages/setuptools-0.6c12dev_r88795-py2.4.egg/setuptools/command/easy_install.py", line 1712, in main
with_ei_usage(lambda:
File "/home/ammon/foo/lib/python2.4/site-packages/setuptools-0.6c12dev_r88795-py2.4.egg/setuptools/command/easy_install.py", line 1700, in with_ei_u
sage
return f()
File "/home/ammon/foo/lib/python2.4/site-packages/setuptools-0.6c12dev_r88795-py2.4.egg/setuptools/command/easy_install.py", line 1716, in <lambda>
distclass=DistributionWithoutHelpCommands, **kw
File "/usr/lib64/python2.4/distutils/core.py", line 149, in setup
dist.run_commands()
File "/usr/lib64/python2.4/distutils/dist.py", line 946, in run_commands
self.run_command(cmd)
File "/usr/lib64/python2.4/distutils/dist.py", line 966, in run_command
cmd_obj.run()
File "/home/ammon/foo/lib/python2.4/site-packages/setuptools-0.6c12dev_r88795-py2.4.egg/setuptools/command/easy_install.py", line 211, in run
self.easy_install(spec, not self.no_deps)
File "/home/ammon/foo/lib/python2.4/site-packages/setuptools-0.6c12dev_r88795-py2.4.egg/setuptools/command/easy_install.py", line 446, in easy_insta
ll
return self.install_item(spec, dist.location, tmpdir, deps)
File "/home/ammon/foo/lib/python2.4/site-packages/setuptools-0.6c12dev_r88795-py2.4.egg/setuptools/command/easy_install.py", line 476, in install_it
em
dists = self.install_eggs(spec, download, tmpdir)
File "/home/ammon/foo/lib/python2.4/site-packages/setuptools-0.6c12dev_r88795-py2.4.egg/setuptools/command/easy_install.py", line 655, in install_eg
gs
return self.build_and_install(setup_script, setup_base)
File "/home/ammon/foo/lib/python2.4/site-packages/setuptools-0.6c12dev_r88795-py2.4.egg/setuptools/command/easy_install.py", line 930, in build_and_
install
self.run_setup(setup_script, setup_base, args)
File "/home/ammon/foo/lib/python2.4/site-packages/setuptools-0.6c12dev_r88795-py2.4.egg/setuptools/command/easy_install.py", line 919, in run_setup
run_setup(setup_script, args)
File "/home/ammon/foo/lib/python2.4/site-packages/setuptools-0.6c12dev_r88795-py2.4.egg/setuptools/sandbox.py", line 61, in run_setup
DirectorySandbox(setup_dir).run(
File "/home/ammon/foo/lib/python2.4/site-packages/setuptools-0.6c12dev_r88795-py2.4.egg/setuptools/sandbox.py", line 105, in run
return func()
File "/home/ammon/foo/lib/python2.4/site-packages/setuptools-0.6c12dev_r88795-py2.4.egg/setuptools/sandbox.py", line 64, in <lambda>
{'__file__':setup_script, '__name__':'__main__'}
File "setup.py", line 110, in ?
File "/usr/lib64/python2.4/distutils/core.py", line 110, in setup
_setup_distribution = dist = klass(attrs)
File "/home/ammon/foo/lib/python2.4/site-packages/setuptools-0.6c12dev_r88795-py2.4.egg/setuptools/dist.py", line 260, in __init__
self.fetch_build_eggs(attrs.pop('setup_requires'))
File "/home/ammon/foo/lib/python2.4/site-packages/setuptools-0.6c12dev_r88795-py2.4.egg/setuptools/dist.py", line 283, in fetch_build_eggs
for dist in working_set.resolve(
File "/home/ammon/foo/lib/python2.4/site-packages/setuptools-0.6c12dev_r88795-py2.4.egg/pkg_resources.py", line 569, in resolve
raise VersionConflict(dist,req) # XXX put more info here
pkg_resources.VersionConflict: (Genshi 0.6dev (/usr/local/lib/python2.4/site-packages/Genshi-0.6dev-py2.4-linux-x86_64.egg), Requirement.parse('Genshi
>=0.6'))
Notice the last line referencing a version conflict with the “old” Genshi at /usr/local/lib/python2.4/site-packages. That’s the system-wide default install. So making explicit that you want to install Trac==0.12 is the way to get it installed in a virtual environment.
Now I just need to figure out how to configure Trac and Subversion using this virtual environment, and copy over a live older version of each.