Re: calling python script from exported bash function, module import fails

[Benjamin Leutner]

Hi,

I could reproduce the issue on another Ubuntu Gnome machine and also on the
plain Ubuntu VirtualBox image from osboxes.org.

Furthermore, I noticed that I don't even need to call the exported 
function.
As long as I pass any function via --env in parallel it will break.
So here's an even shorter example to reproduce it in the virtualbox image:

Image: 64bit Ubuntu Yakkety Yak
http://www.osboxes.org/ubuntu/


sudo apt install python-setuptools
(wget -O - pi.dk/3 || curl pi.dk/3/) | sudo bash

function fun {
    echo $1
}
export -f fun

## Works fine
parallel  'python -c "import setuptools"' ::: 2

## Breaks
parallel --env fun 'python -c "import setuptools"' ::: 2



I tried calling uname -p also from inside the python code and it returns 
'x86_64' correctly in both cases.






On 23.12.2016 01:24, Ole Tange wrote:
> On Thu, Dec 22, 2016 at 5:28 PM, Benjamin Leutner
> <benjamin.leutner@uni-wuerzburg.de> wrote:
>
> > Here's the modified example:
> >
> > function FUN {
> > echo -e "\n----- Try number: ${1}  -----"
> > echo "Host: $(hostname), Level:  $SHLVL"
> > python -c "
> > import setuptools
> > print 'import succesful'"
> > }
> > export -f FUN
> >
> > # without env
> > parallel 'FUN {}' ::: 1
> >
> > # with env for function
> > parallel --env FUN 'FUN {}' ::: 2
> >
> > # with env for everything
> > parallel --env _ 'FUN {}' ::: 3
> All work for me. So this is a local problem on your machine.
>
> Therefore see if you can reproduce the error on one of these
> VirtualBox images:
> http://sourceforge.net/projects/virtualboximage/files/
> http://www.osboxes.org/virtualbox-images/
>
> > 1) is fine, 2) and 3) give me :
> > Traceback (most recent call last):
> >    File "<string>", line 2, in <module>
> >    File "/usr/lib/python2.7/dist-packages/setuptools/__init__.py", line 14,
> > in <module>
> >      from setuptools.extension import Extension
> >    File "/usr/lib/python2.7/dist-packages/setuptools/extension.py", line 10,
> > in <module>
> >      from .dist import _get_unpatched
> >    File "/usr/lib/python2.7/dist-packages/setuptools/dist.py", line 22, in
> > <module>
> >      from setuptools import windows_support
> >    File "/usr/lib/python2.7/dist-packages/setuptools/windows_support.py",
> > line 11, in <module>
> >      @windows_only
> >    File "/usr/lib/python2.7/dist-packages/setuptools/windows_support.py",
> > line 6, in windows_only
> >      if platform.system() != 'Windows':
> >    File "/usr/lib/python2.7/platform.py", line 1286, in system
> >      return uname()[0]
> >    File "/usr/lib/python2.7/platform.py", line 1253, in uname
> >      processor = _syscmd_uname('-p','')
> >    File "/usr/lib/python2.7/platform.py", line 988, in _syscmd_uname
> >      rc = f.close()
> > IOError: [Errno 10] No child processes
> The traceback indicates Python tries to run system("uname", "-p"), but
> fails due to no child process.
>
>
> /Ole


--
Benjamin Leutner M.Sc.
PhD candidate

Department of Remote Sensing
University of Wuerzburg
Campus Hubland Nord 86
97074 Wuerzburg, Germany

Tel: +49-(0)931-31 89594
Email: benjamin.leutner@uni-wuerzburg.de
Web: http://www.fernerkundung.uni-wuerzburg.de