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Beginners Guide : pip and virtualenv

68 points by myusuf3 15y ago

flexterra 15y ago
You should try virtualenvwrapper, it makes the process of activating and changing between virtualenvs a breeze.
- myusuf3 15y ago
  upcoming post :P
- stock_toaster 15y ago
  I liked virtualenvwrapper, but it added considerable (noticable) latency to my terminal startups. I ended up removing it and went back to manual virtualenv activation (with a couple of small helper bash functions of course).
  - antrix 15y ago
    Same here. At times, it gets so bad that I have to hit Ctrl+C and then it dumps out a nice big trace before giving me my shell prompt.
    - myusuf3 15y ago
      I have never seen that. it just loads a script into path. interesting.
pyre 15y ago
Also worth mentioning pythonbrew which goes a step further and allows you to manage separate Python builds.
pdubroy 15y ago
One of the nice things about virtualenv is that it installs a copy of pip into every virtual environment you create. If you always have one of the environments active, there's no need to even install pip globally.
- Pewpewarrows 15y ago
  Except for when you DO want to install a package globally. Utilities like pyflakes and fabric, for example.
  - pdubroy 15y ago
    On my personal machines (effectively single-user), I find there's no need to install packages globally. I have a default virtual environment that I activate in my .profile, and anything that's not project-specific gets installed there. Not saying everyone should do this, but it works well for me.
    - myusuf3 15y ago
      thats such a hassle. though, why dont you just install global requirements in the base machine, you wont always have to keep turning on virtualenvs.
2mur 15y ago
Nice article. I use virtualenv heavily and still do the symlinking dance. I keep my django trunk in a ~/libraries folder and symlink the django folder to the /path/to/virtualenv/lib/pythonX.X/site-packages folder. I'm not sure that I have a compelling reason for doing so.
- izak30 15y ago
  cd ~Path/to/django; pip install -e .; It feels better than symlinking to me. I would really only do this if I had a custom patched django though. If speed/bandwidth is a concern, just make sure your pip cache is setup properly.
- myusuf3 15y ago
  I would suggest to stop doing that since thats the point of virtualenv; it is a bit of pain since it doesn't put django-admin.py in path but you can always refer to it.
waterside81 15y ago
pip & virtualenv saved me a world of hurt upgrading from Snow Leopard to Lion. The upgrade completely wiped out any global packages I had in Python/2.6 - so I did lose a few packages that I needed to rebuild, but not many.

68 points by myusuf3 15y ago

flexterra 15y ago

You should try virtualenvwrapper, it makes the process of activating and changing between virtualenvs a breeze.

myusuf3 15y ago
upcoming post :P
stock_toaster 15y ago
I liked virtualenvwrapper, but it added considerable (noticable) latency to my terminal startups. I ended up removing it and went back to manual virtualenv activation (with a couple of small helper bash functions of course).
- antrix 15y ago
  Same here. At times, it gets so bad that I have to hit Ctrl+C and then it dumps out a nice big trace before giving me my shell prompt.
  - myusuf3 15y ago
    I have never seen that. it just loads a script into path. interesting.

pyre 15y ago

Also worth mentioning pythonbrew which goes a step further and allows you to manage separate Python builds.

pdubroy 15y ago

One of the nice things about virtualenv is that it installs a copy of pip into every virtual environment you create. If you always have one of the environments active, there's no need to even install pip globally.

Pewpewarrows 15y ago
Except for when you DO want to install a package globally. Utilities like pyflakes and fabric, for example.
- pdubroy 15y ago
  On my personal machines (effectively single-user), I find there's no need to install packages globally. I have a default virtual environment that I activate in my .profile, and anything that's not project-specific gets installed there. Not saying everyone should do this, but it works well for me.
  - myusuf3 15y ago
    thats such a hassle. though, why dont you just install global requirements in the base machine, you wont always have to keep turning on virtualenvs.

2mur 15y ago

Nice article. I use virtualenv heavily and still do the symlinking dance. I keep my django trunk in a ~/libraries folder and symlink the django folder to the /path/to/virtualenv/lib/pythonX.X/site-packages folder. I'm not sure that I have a compelling reason for doing so.

izak30 15y ago
cd ~Path/to/django; pip install -e .; It feels better than symlinking to me. I would really only do this if I had a custom patched django though. If speed/bandwidth is a concern, just make sure your pip cache is setup properly.
myusuf3 15y ago
I would suggest to stop doing that since thats the point of virtualenv; it is a bit of pain since it doesn't put django-admin.py in path but you can always refer to it.

waterside81 15y ago

pip & virtualenv saved me a world of hurt upgrading from Snow Leopard to Lion. The upgrade completely wiped out any global packages I had in Python/2.6 - so I did lose a few packages that I needed to rebuild, but not many.