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views:

193

answers:

2

I use this bit of code in my script to pinpoint, in a cross-platform way, where exactly it's being run from:

SCRIPT_ROOT = os.path.dirname(os.path.realpath(__file__))

Pretty simple. I then go on to use SCRIPT_ROOT in other areas of my script to make sure everything is properly relative. My problem occurs when I run it through py2exe, because the generated executable doesn't set __file__, therefore my script breaks. Does anyone know how to fix or work around this?

+1  A: 

Try this:

import os
import sys
os.path.realpath(os.path.dirname(sys.argv[0]))
prestomation
+3  A: 

Here is the py2exe documentation reference and here are the relevant items:

  • sys.executable is set to the full pathname of the exe-file.
  • The first item in sys.argv is the full pathname of the executable, the rest are the command line arguments.
  • sys.frozen only exists in the executable. It is set to "console_exe" for a console executable, to "windows_exe" for a console-less gui executable, and to "dll" for a inprocess dll server.
  • __file__ is not defined (you might want to use sys.argv[0] instead)

It is not apparent from those docs whether "the exe-file" and "the executable" are the same thing, and thus whether sys.executable and sys.argv[0] are the same thing. Looking at code that worked for both script.py and py2exe_executable.exe last time I had to do this, I find something like:

if hasattr(sys, 'frozen'):
    basis = sys.executable
else:
    basis = sys.argv[0]
required_folder = os.path.split(basis)[0]

As I say that worked, but I don't recall why I thought that was necessary instead of just using sys.argv[0].

Using only basis was adequate for the job in hand (read files in that directory). For a more permanent record, split something like os.path.realpath(basis).

Update Actually did a test; beats guesswork and armchair pontification :-)

Summary: Ignore sys.frozen, ignore sys.executable, go with sys.argv[0] unconditionally.

Evidence:

=== foo.py ===

# coding: ascii
import sys, os.path
print 'sys has frozen:', hasattr(sys, 'frozen')
print 'using sys.executable:', repr(os.path.dirname(os.path.realpath(sys.executable)))
print 'using sys.argv[0]:',    repr(os.path.dirname(os.path.realpath(sys.argv[0]   )))

=== setup.py ===

from distutils.core import setup
import py2exe
setup(console=['foo.py'])

=== results ===

C:\junk\so\py2exe>\python26\python foo.py
sys has frozen: False
using sys.executable: 'C:\\python26'
using sys.argv[0]: 'C:\\junk\\so\\py2exe' # where foo.py lives

C:\junk\so\py2exe>dist\foo
sys has frozen: True
using sys.executable: 'C:\\junk\\so\\py2exe\\dist'
using sys.argv[0]: 'C:\\junk\\so\\py2exe\\dist' # where foo.exe lives
John Machin
I believe that sys.executable usually points to the python interpreter itself, which is what you want under py2exe, but not otherwise.
prestomation
@prestomation: What is "the Python interpreter itself" in the py2exe case? What do you mean by "but not otherwise"?
John Machin
@John "otherwise" is when you are running an interpreted file, which is most environments. In the py2exe case, I would imagine the interpreter is your py2exe, because it's included. It looks like your most recent edit confirms that.
prestomation