virtualenv and Maya

Question

I'm trying to set up virtualenv to point at Maya 2013's executable so I can run unit tests inside it from the shell. Maya uses a custom python 2.6 executable located at /usr/autodesk/maya/bin/mayapy. I get these errors:

$ virtualenv -p /usr/autodesk/maya/bin/mayapy mayapy
Running virtualenv with interpreter /usr/autodesk/maya/bin/mayapy
PYTHONHOME is set.  You *must* activate the virtualenv before using it
Traceback (most recent call last):
  File "/usr/local/lib/python2.6/dist-packages/virtualenv.py", line 2577, in <module>
    main()
  File "/usr/local/lib/python2.6/dist-packages/virtualenv.py", line 979, in main
    no_pip=options.no_pip)
  File "/usr/local/lib/python2.6/dist-packages/virtualenv.py", line 1081, in create_environment
    site_packages=site_packages, clear=clear))
  File "/usr/local/lib/python2.6/dist-packages/virtualenv.py", line 1289, in install_python
    writefile(site_filename_dst, SITE_PY)
  File "/usr/local/lib/python2.6/dist-packages/virtualenv.py", line 445, in writefile
    f = open(dest, 'wb')
IOError: [Errno 2] No such file or directory: 'mayapy/lib/python26.zip/site.py'

I've read virtualenv's page, the output of virtualenv -h, a few basic virtualenv writeups like this one, and searched google and SO for both virtualenv and maya+virtualenv pairings, all to no avail.

Here's the verbose output:

$ virtualenv -vv -p /usr/autodesk/maya/bin/mayapy mayapy
Running virtualenv with interpreter /usr/autodesk/maya/bin/mayapy
PYTHONHOME is set.  You *must* activate the virtualenv before using it
Directory mayapy/lib/python2.6 already exists
Symlinking Python bootstrap modules
  Cannot import bootstrap module: os
  Ignoring built-in bootstrap module: posix
  Cannot import bootstrap module: posixpath
  Cannot import bootstrap module: nt
  Cannot import bootstrap module: ntpath
  Cannot import bootstrap module: genericpath
  Cannot import bootstrap module: fnmatch
  Cannot import bootstrap module: locale
  Cannot import bootstrap module: encodings
  Cannot import bootstrap module: codecs
  Cannot import bootstrap module: stat
  Cannot import bootstrap module: UserDict
  File mayapy/lib/python2.6/lib-dynload/readline.so already exists
  Cannot import bootstrap module: copy_reg
  Cannot import bootstrap module: types
  Cannot import bootstrap module: re
  Cannot import bootstrap module: sre
  Cannot import bootstrap module: sre_parse
  Cannot import bootstrap module: sre_constants
  Cannot import bootstrap module: sre_compile
  File mayapy/lib/python2.6/lib-dynload/zlib.so already exists
  Cannot import bootstrap module: warnings
  Cannot import bootstrap module: linecache
  Cannot import bootstrap module: _abcoll
  Cannot import bootstrap module: abc
Directory mayapy/lib/python2.6/site-packages already exists
Writing mayapy/lib/python26.zip/site.py
Traceback (most recent call last):
  File "/usr/local/lib/python2.6/dist-packages/virtualenv.py", line 2577, in <module>
    main()
  File "/usr/local/lib/python2.6/dist-packages/virtualenv.py", line 979, in main
    no_pip=options.no_pip)
  File "/usr/local/lib/python2.6/dist-packages/virtualenv.py", line 1081, in create_environment
    site_packages=site_packages, clear=clear))
  File "/usr/local/lib/python2.6/dist-packages/virtualenv.py", line 1289, in install_python
    writefile(site_filename_dst, SITE_PY)
  File "/usr/local/lib/python2.6/dist-packages/virtualenv.py", line 445, in writefile
    f = open(dest, 'wb')
IOError: [Errno 2] No such file or directory: 'mayapy/lib/python26.zip/site.py'

Answer 1

An alternative that's good for unittesting without messing with your maya runtime environment is to run your tests inside an instance of maya.standalone. If your tests all include something like this:

import maya.standalone
try: 
    maya.standalone.initialize()
except:
    pass # initialize raises if you call it more than once, but it's harmless if you catch it.

you can run them from the mayapy intepreter without running maya in gui mode.

Answer 2

Download the latest virtualenv and call it virtualenv with the version of python you want to virtualize:

/usr/autodesk/maya/bin/mayapy where/i/saved/virtualenv mayapy