Ipython: IPython installed within virtualenv. WARNING "Please install IPython inside the virtualtenv"

[amelio-vazquez-reina]

I have installed the latest stable version of IPython within a virtualenv created with the latest stable version of virtualenv on the latest Python 2.7 and I still got a warning saying that I should install IPython inside the virtualenv.

In case there are any doubts, I created a virtualenv and activated it with source [virtenv]/bin/activate, then installed ipython with pip install ipython. To make sure I was running the right ipython, I did which ipython it correctly points to the ipython binary within the virtual environment. Yet, when I call ipython, I get the WARNING message:

WARNING: Attempting to work in a virtualenv. If you encounter problems, please install IPython inside the virtualenv.

Why do I get the warning?

[minrk]

Try printing these from inside IPython:

import os, sys, IPython
print os.environ['VIRTUAL_ENV']
print sys.executable
print IPython.__file__
print sys.path

[amelio-vazquez-reina]

Thanks @minrk. Below are the outputs:

Before I call IPython from the command line, my prompt correctly shows as:
([name of virtual env]) [my regular prompt]

Then, once I am in IPython:

print os.environ['VIRTUAL_ENV']
# correctly prints the path to the environment 

print sys.executable
# Prints the external path to Python (?)

print IPython.__file__
# Prints the external path to the ipython installation's __init__.pyc (?)

print sys.path
# Prints the path to the site-packages folder from the virtualenv at the top.
# Then the bin path of the Python's external installation (?)
# Then some paths to individual packages from the external installation (?)
# Then the paths to individual packages from the virtualenv (and it misses the virtualenv's installation of IPython, ?)
# Then a few more paths to individual packages of the external installation (?)
# Finally the IPython from the external installation (?)

If I exit my IPython session, my prompt correctly shows as:
([name of virtual env]) [my regular prompt]

To clarify, when I say external installation_, I mean an installation _not* within the virtualenv, and not part of a system installation either, but one that I have included at the top of $PATH and of $LD_LIBRARY_PATH and that I know works correctly.

Perhaps there is an environment variable that I am missing and that is confusing IPython to believe that I am using the system installation and not the external installation that I want to use in combination with my virtualenv and that I include at the beginning of PATH and LD_LIBRARY_PATH ?

[minrk]

what do you get with head $(which ipython)?

[minrk]

one more: sys.argv

[minrk]

If sys.executable is wrong, then things went awry before any Python packages were loaded. This is precisely what would happen if the system ipython was instead of one installed into the env (e.g. if you did /usr/bin/ipython with the env active, which we should all expect to be badly behaved).

[minrk]

It's possible the fix is as simple as a hash -r, can you try that?

[amelio-vazquez-reina]

Thanks @minrk. head $(which ipython) returns:

#!/path_to_my_virtual_env/bin/python
# EASY-INSTALL-ENTRY-SCRIPT: 'ipython==0.13.1','console_scripts','ipython'
__requires__ = 'ipython==0.13.1'
import sys
from pkg_resources import load_entry_point

sys.exit(
   load_entry_point('ipython==0.13.1', 'console_scripts', 'ipython')()
)

And print sys.argv returns the path to the external Python installation.

[amelio-vazquez-reina]

Running hash -r from the terminal seems to have worked!

I now get a different warning though
WARNING: IPython History requires SQLite, your history will not be saved

which is interesting, since I don't get this message if I deactivate my virtualenv and run ipython from the external installation.

[minrk]

I assume this is what you did:

1. you ran ipython and saw this warning
2. you installed ipython into the env
3. in the same shell session, you tried to run ipython again

Here's the relevant info, and why hash -r fixed it:

• The path of commands is cached after you called them, so it doesn't actually search your PATH for a given command more than once in a shell session.
• which is not aware of this cache, so which ipython does not necessarily point to the ipython that will be called if it has been called before in the shell session.
• hash -r simply resets this cache, so that which will be accurate once again.

As for sqlite, what Python did you use for the virtualenv?

[amelio-vazquez-reina]

@minrk Yes, that's correct! Thanks. I am using Python 2.7 x64

[minrk]

Did you build Python yourself? If so, you need to make sure libsqlite is present and available when you compile Python.

[amelio-vazquez-reina]

Thanks @minrk. libsqlite seems to be available to the external IPython, i.e. the one I run when I do not activate the virtual environment (although this is not the one from the system installation, since I have modified PATH and LD_LIBRARY_PATH to include an external installation at the top). That said, I guess that it's possible that the external IPython is using libsqlite from the system installation (probably from other paths in LD_LIBRARY_PATH). Would that be possible?

Either way, thanks again for all your help. The original issue I reported is solved, so we can safely close the ticket.

[minrk]

it's generally a compile time issue - I think you need the headers, etc. (you can't fix it without recompiling Python)

[jacksonjack]

I set the .py profile executive software to Notebook,so it never did run!
Then ,I find it！
Thank you!