Issue importing subprocess32

Question

I am trying to install subprocess32 with my python 2.7 installation via buildroot. It appeared to install correctly but when I import it on the embedded system I get an error:

>>> import subprocess32
/usr/lib/python2.7/site-packages/subprocess32.py:472: RuntimeWarning: The _posixsubprocess module is not being used. Child process reliability may suffer if your pro
gram uses threads.
  "program uses threads.", RuntimeWarning)

Following this path I tried to import _posixsubprocess

import _posixsubprocess
Traceback (most recent call last):
  File "<stdin>", line 1, in <module>
ImportError: dynamic module does not define init function (init_posixsubprocess)

subprocess32 seems to have it's own version and it's not working in this case?

Here is my make file:

#############################################################
#
# Subprocess32 module for python
#
#############################################################

SUBPROCESS32_VERSION = 3.2.7
SUBPROCESS32_SOURCE = subprocess32-$(SUBPROCESS32_VERSION).tar.gz
SUBPROCESS32_SITE = https://pypi.python.org/pypi/subprocess32

SUBPROCESS32_DEPENDENCIES = python

define SUBPROCESS32_BUILD_CMDS
        (cd $(@D); $(HOST_DIR)/usr/bin/python setup.py build)
endef

define SUBPROCESS32_INSTALL_TARGET_CMDS
        (cd $(@D); $(HOST_DIR)/usr/bin/python setup.py install --prefix=$(TARGET_DIR)/usr)
endef

$(eval $(call GENTARGETS,package,subprocess32))

There is a similar post about this Python Error The _posixsubprocess module is not being used However the answer is a link in the comments which is dead. Any ideas for my problem?

setup.py:

#!/usr/bin/python

import os
import sys
from distutils.core import setup, Extension


def main():
    if sys.version_info[0] != 2:
        sys.stderr.write('This backport is for Python 2.x only.\n')
        sys.exit(1)

    ext = Extension('_posixsubprocess', ['_posixsubprocess.c'],
                    depends=['_posixsubprocess_helpers.c'])
    if os.name == 'posix':
        ext_modules = [ext]
    else:
        ext_modules = []

    setup(
      name='subprocess32',
      version='3.2.7',
      description='A backport of the subprocess module from Python 3.2/3.3 for use on 2.x.',
      long_description="""
This is a backport of the subprocess standard library module from
Python 3.2 & 3.3 for use on Python 2.
It includes bugfixes and some new features.  On POSIX systems it is
guaranteed to be reliable when used in threaded applications.
It includes timeout support from Python 3.3 but otherwise matches
3.2's API.  It has not been tested on Windows.""",
      license='PSF license',

      maintainer='Gregory P. Smith',
      maintainer_email='[email protected]',
      url='https://github.com/google/python-subprocess32',

      ext_modules=ext_modules,
      py_modules=['subprocess32'],

      classifiers=[
          'Intended Audience :: Developers',
          'Topic :: Software Development :: Libraries',
          'Development Status :: 5 - Production/Stable',
          'License :: OSI Approved :: Python Software Foundation License',
          'Operating System :: POSIX',
          'Operating System :: POSIX :: BSD',
          'Operating System :: POSIX :: Linux',
          'Operating System :: POSIX :: SunOS/Solaris',
          'Programming Language :: Python :: 2.4',
          'Programming Language :: Python :: 2.5',
          'Programming Language :: Python :: 2.6',
          'Programming Language :: Python :: 2.7',
          'Programming Language :: Python :: 2 :: Only',
          'Programming Language :: Python :: Implementation :: CPython',
      ],
    )


if __name__ == '__main__':
    main()

Mesencephalon

Answer 1

The issue was that distutils was using the wrong compiler for building shared objects (other objects used the right compiler). Setting the below LDSHARED variable during the build phase solved the issue:

 LDSHARED="$(TARGET_CC) -pthread -shared"

Mesencephalon

Answer 2

I'm not sure which Buildroot version you're using, but if it's still a version that uses the GENTARGETS macro and that doesn't have the python-package infrastructure, then it must be a really, really, really old version. Please upgrade first, as many, many fixes have been made in recent years in the Python support.

Feet

To be honest I don't even know what version of buildroot it is, yes it is old but upgrading it is not an option right now. I'm not sure if the issue is with it or subprocess32 also. That big of a change would have many problems happening elsewhere as well I think. – Mesencephalon