Create a gist now

Instantly share code, notes, and snippets.

What would you like to do?
Prototype of an extension to provide acess to virtual python environment on an IPython notebook cell
# -*- coding: utf-8 -*-
Tests for the virtualenvmagic extension
Author: Flávio Codeço Coelho - @fccoelho
import os
import as nt
def setup():
ip = get_ipython()
def test_virtualenv():
ip = get_ipython()
result = ip.run_cell_magic('virtualenv','pypyEnv','import sys;print sys.version')
nt.assert_true('PyPy' in result)
# -*- coding: utf-8 -*-
Virtualenv magic
Requires virtualenv and virtualenv Wrapper
Author: Flávio Codeço Coelho - @fccoelho
Thanks to @turicas for helpful tips
import sys
import os
import shlex
from subprocess import Popen, PIPE
from IPython.core.magic import cell_magic
def virtualenv(line, cell):
This magic enables the execution of code in a cell on a
pre-existing virtual env. It Requires Virtualenv and VirtualenvWrapper
to be installed in the system.
The virtual env to be used must be created in advance.
To activate this magic just write at the top of the cell:
%%virtualenv my_env
import sys
print sys.version
if not os.path.exists(os.environ['WORKON_HOME']+'/'+line):
print >> sys.stderr, "Environment {} does no exist.".format(line)
env_activate_cmd = 'bash -c "source {}/{}/bin/activate && python -"'.format(os.environ['WORKON_HOME'],line)
cmd = shlex.split(env_activate_cmd)
p = Popen(cmd, stdout=PIPE, stderr=PIPE, stdin=PIPE)
out,err = p.communicate(cell)
if err:
print >> sys.stderr, err
return out
_loaded = False
def load_ipython_extension(ip):
"""Load the extension in IPython."""
global _loaded
if not _loaded:
if 'WORKON_HOME' in os.environ:
ip.register_magic_function(virtualenv, 'cell')
_loaded = True
print >> sys.stderr, "You must have Virtualenv and VirtualenvWrapper installed."

fccoelho commented Jun 5, 2012

@minrk : Would this be a start of a virtualenv cell?

it requires virtualenv to be installed and the env to exist prior to using this

Rather than calling get_ipython() or InteractiveShell(), an IPython extension should offer a load_ipython_extension(ip) method, which will be called with the shell object when it's loaded. Docs:

(The rationale for this is that we have a long term goal to allow more than one InteractiveShell object in the same process - so we're trying not to treat it like a singleton)


fccoelho commented Jun 7, 2012

I'll study other extensions and modify my code to conform.
thanks @takluyver


fccoelho commented Jun 8, 2012

Thanks @turicas for the tip on how to make the bash command work...

turicas commented Jun 9, 2012

@fccoelho, PEP8, please! :-)

Sign up for free to join this conversation on GitHub. Already have an account? Sign in to comment