Installation OSError: [Errno 2] No such file or directory

Hi,

I'm trying to follow the installation guide but when I tried to run the using codejail code on xserver devstack vangrat server:

import codejail.jail_code
codejail.jail_code.configure('python', '/bin/python')
import codejail.safe_exec
codejail.safe_exec.safe_exec("import os\nos.system('ls /etc')", {})

I got (OSError: [Errno 2] No such file or directory) error:

(xserver)xserver@precise64:/edx/app/xserver/xserver$ python
Python 2.7.3 (default, Feb 27 2014, 19:58:35) 
[GCC 4.6.3] on linux2
Type "help", "copyright", "credits" or "license" for more information.
>>> import codejail.jail_code                                                                                                                         
>>> codejail.jail_code.configure('python', '/edx/app/xserver/venvs/xserver/bin/python')                                                   
>>> import codejail.safe_exec
>>> codejail.safe_exec.safe_exec("import os\nos.system('ls /etc')", {})
Traceback (most recent call last):
  File "<stdin>", line 1, in <module>
  File "/edx/app/edxapp/venvs/edxapp/src/codejail/codejail/safe_exec.py", line 137, in safe_exec
    "python", code=jailed_code, stdin=stdin, files=files, slug=slug,
  File "/edx/app/edxapp/venvs/edxapp/src/codejail/codejail/jail_code.py", line 208, in jail_code
    stdout=subprocess.PIPE, stderr=subprocess.PIPE,
  File "/usr/lib/python2.7/subprocess.py", line 679, in __init__
    errread, errwrite)
  File "/usr/lib/python2.7/subprocess.py", line 1249, in _execute_child
    raise child_exception
OSError: [Errno 2] No such file or directory

Debugging codejail I found that if user is None at def configure(command, bin_path, user=None): master/codejail/jail_code.py#L26

The commands cmd at subproc = subprocess.Popen master/codejail/jail_code.py#L219 is ['TMPDIR=tmp', '/edx/app/xserver/venvs/xserver/bin/python', '-E', '-B', 'jailed_code']. Because 'TMPDIR=tmp' is the first parameter to subprocess.Popen subprocess return OSError: [Errno 2] No such file or directory.

Otherwise if I add an user (sandbox) it seems to work:

>>> codejail.jail_code.configure('python', '/edx/app/xserver/venvs/xserver/bin/python', 'sandbox')
>>> codejail.safe_exec.safe_exec("import os\nos.system('ls /etc')", {})

cmd at subproc = subprocess.Popenmaster/codejail/jail_code.py#L219 is ['sudo', '-u', 'sandbox', 'TMPDIR=tmp', '/edx/app/xserver/venvs/xserver-sandbox/bin/python', '-E', '-B', 'jailed_code']

Is codejail work without an user?

Start in codejail/jail_code.py at configure() and the subprocess.Popen call around line 219. Reproduce the installation-guide example without a user and inspect how the command is assembled. Done means the no-user configuration no longer produces OSError: [Errno 2], or the supported requirement is made explicit.