Can't install packages using pip in Virtualenv on remote using Fabric

Question

I have being using fabric to deploy an app with virtualenv. I was using fabric 1.4 and upgraded to 1.5.1 last week. My script stopped working.

It can't install the requirements. It seems it's not activating the virtualenv. In my code, I have:

with cd('%(path)s' % env):
        with prefix('source bin/activate'):
            run('pip install -U distribute')

I'm getting a permission denied error: error: could not delete '/usr/local/lib/python2.7/dist-packages/pkg_resources.py': Permission denied

The command being executed is:

Executed: /bin/bash -l -c "cd /var/www/myproject && source bin/activate && export PATH=\"\\$PATH:\\"/var/www/myproject\\" \" && pip install -U distribute"

If I ssh to the remote machine and run cd /var/www/myproject && source bin/activate && pip install -U distribute, it works just fine.

Why is my fabric script not working?

Thanks in advance

I have a slight suspicion that having fabric instantiate a virtualenv on a target host might have unwanted results.. — favoretti, Dec 27 '12 at 19:09
According to this link, it's possible, but I don't get what I'm doing wrong. http://stackoverflow.com/questions/1180411/activate-a-virtualenv-via-fabric-as-deploy-user — duduklein, Dec 27 '12 at 19:13
Well, the only difference is, you're using `run()`, rather than `sudo()`, which might be a permission issue. Try using `sudo()`? — favoretti, Dec 27 '12 at 19:29
it's strange, because as I'm in a virtualenv, it should not require sudo — duduklein, Dec 27 '12 at 19:32
It depends who created the virtualenv and whether you can do it as your own user. Other point is, fabric really executes command with that `/bin/bash -l -c "..."` prefix, if you do that as the user fabric uses on the machine, does it work as well? — favoretti, Dec 27 '12 at 19:33
using sudo, the packages are not installed in the virtualenv. I'm using the same user as fabric — duduklein, Dec 27 '12 at 19:36
Aha, so basically it means sourcing the venv fails. What if you do `source /full/path/to/bin/activate` instead of relative path? Despite the `with cd()`... — favoretti, Dec 27 '12 at 19:40

score 6 · Accepted Answer · answered Jan 31 '13 at 15:48

6

Instead of the serial approach with..

source bin/activate
pip install -U distribute

..directly use the pip executable of the virtualenv:

myenv/bin/pip install -U distribute

answered Jan 31 '13 at 15:48

Jasper van den Bosch

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score 3 · Answer 2 · answered Dec 28 '12 at 12:32

Although not exactly a solution, fabtools has a number of functions related to virtualenvs that are very handy. They do (almost) all of the hard work for you, and are probably worth using to check it isn't something else going wrong.

# Cut (and modified) from the fabtools documentation
from fabric.api import *
from fabtools import require
import fabtools

@task
def setup():
    # Require a Python package
    with fabtools.python.virtualenv('/home/myuser/env'):
        require.python.package('pyramid')

Can't install packages using pip in Virtualenv on remote using Fabric

2 Answers2