Develop Reference

Python on Gentoo is missing sqlite

I use a Gentoo-based Docker image for CI with multiple versions of Python. Recently, I've started experiencing errors because one tool (coveralls) requires sqlite, which is missing. sqlite is part of the Python standard library.
This can be checked from the command line
>>> removing all .pyc files
>>> executing command
me#5b35f99c08af /source $ python
Python 3.6.9 (default, Dec 27 2019, 12:15:49)
[GCC 7.3.0] on linux
Type "help", "copyright", "credits" or "license" for more information.
>>> import sqlite3
Traceback (most recent call last):
File "<stdin>", line 1, in <module>
ModuleNotFoundError: No module named 'sqlite3'
I couldn't find any notes in the Gentoo packaging database about this, but I'm not really familiar with it as an OS. I assume there must have been a problem building some relevant library.
Python has been installed like this:
RUN emerge -q -u dev-lang/python:3.6
But the error occurs for all the versions I'm currently testing with: >= 3.5. Any ideas as to what I'm doing wrong?

Importing asyncio throws error

In my terminal, I wanted to test something with asyncio. Here's what I did:
$ python3.6
Python 3.6.2 (v3.6.2:5fd33b5926, Jul 16 2017, 20:11:06)
[GCC 4.2.1 (Apple Inc. build 5666) (dot 3)] on darwin
Type "help", "copyright", "credits" or "license" for more information.
>>> import asyncio
And this threw an error as follows:
Traceback (most recent call last):
File "<stdin>", line 1, in <module>
File "/Library/Frameworks/Python.framework/Versions/3.6/lib/python3.6/asyncio/__init__.py", line 42, in <module>
tasks.__all__ +
AttributeError: module 'asyncio.tasks' has no attribute '__all__'
Why does it throw this error, and how can I fix it? (I checked in my python 3.5 interpreter the same way and got no error, so maybe the library got corrupted?)
I've run Python with the -v switch, the output produced after running import asyncio at the prompt is rather large, so it is available in this GitHub gist.

Your local installation has been corrupted. From the python -v output you provided:
# bytecode is stale for 'asyncio.tasks'
# code object from /Library/Frameworks/Python.framework/Versions/3.6/lib/python3.6/asyncio/tasks.py
import 'asyncio.tasks' # <_frozen_importlib_external.SourceFileLoader object at 0x104cf7860>
The bytecode is stale message means that asyncio/tasks.py file is newer than the accompanying asyncio/__pycache__/tasks.cpython-36.pyc file. This indicates that something has altered the tasks.py file, causing the contents to be different from what was shipped with your Python binary.
For comparison, the sibling module asyncio.events was loaded from the bytecode cache, which was provided by the Python installer at install time:
# code object from '/Library/Frameworks/Python.framework/Versions/3.6/lib/python3.6/asyncio/__pycache__/events.cpython-36.pyc'
import 'asyncio.events' # <_frozen_importlib_external.SourceFileLoader object at 0x104ccf4e0>
The code object for that module was loaded from the asyncio/__pycache__/events.cpython-36.pyc file.
You could re-install Python from the OS X installer, but at this point I'd just grab the newer 3.6.5 release instead.
You could also try to re-instate the original contents by downloading the original source from the v3.6.2 tag, but then you'll have to make sure the bytecode is regenerated (run sudo python -m compileall /Library/Frameworks/Python.framework/Versions/3.6/lib/python3.6/asyncio/tasks.py) and you'll need to check for any other such changed files (try find /Library/Frameworks/Python.framework/Versions/3.6/lib/python3.6 -name \*.py -newer /Library/Frameworks/Python.framework/Versions/3.6/lib/python3.6/asyncio/__init__.py)

It seems that it's a bug
Try to upgrade your Python via brew
brew upgrade python3
Currently, Python 3.6.5 is available and there is no such problem

Python 2 Bindings Net-SNMP Error - undefined symbol: netsnmp-memdup

I successfully compiled net-snmp-5.7.3 on Ubuntu. :D This is the specific version of Ubuntu:
Linux loserBox 3.13.0-32-generic #57-Ubuntu SMP Tue Jul 15 03:51:08 UTC 2014 x86_64 x86_64 x86_64 GNU/Linux
I seemed to have successfully installed the Python bindings for net-snmp too. This is included with the net-nsmp download as a different folder titled 'Python' with the setup.py file in it. However when running the command python setup.py test I noticed some problems. I thought this may be nothing to worry about so I went ahead and executed python setup.py install I was not sure what the instructions meant in the README file that say, "python setup.py test (requires a locally running agent w/ config provided)". So, this is why I installed it with the failed test or something. Anyways, I am not sure if this is a problem or not.
After successfully installing the python bindings for net-snmp I switched directories back to my Desktop and opened up an interactive python shell. From here I imported the netsnmp module and received the below error. It almost looks like there is a spelling error in the variable netsnmp_memdup that is throwing the error in the Traceback. This looks like a problem with the C code and not python.
Python 2.7.6 (default, Mar 22 2014, 22:59:56)
[GCC 4.8.2] on linux2
Type "help", "copyright", "credits" or "license" for more information.
>>> import netsnmp
/usr/lib/python2.7/dist-packages/pkg_resources.py:1031: UserWarning:
/home/loser_user/.python-eggs is writable by group/others and vulnerable to attack
when used with get_resource_filename. Consider a more secure location
(set with .set_extraction_path or the PYTHON_EGG_CACHE environment variable).
warnings.warn(msg, UserWarning)
Traceback (most recent call last):
File "<stdin>", line 1, in <module>
File "build/bdist.linux-x86_64/egg/netsnmp/__init__.py", line 1, in <module>
File "build/bdist.linux-x86_64/egg/netsnmp/client.py", line 1, in <module>
File "build/bdist.linux-x86_64/egg/netsnmp/client_intf.py", line 7, in <module>
File "build/bdist.linux-x86_64/egg/netsnmp/client_intf.py", line 6, in __bootstrap__
ImportError: /home/loser_user/.python-eggs/netsnmp_python-1.0a1-py2.7-linux-x86_64.egg-
tmp/netsnmp/client_intf.so: undefined symbol: netsnmp_memdup
Does anyone know how to fix this problem? I looked on the mailing list page on sourceforge for this project and searched the supoort archives but did not find anything.
Thanks for listening to a crazy man's Python problems.
Happy Holidays,
user_loser

Alrgihty, thanks to my good friend Naveen, we have traced this down to an actual bug in the Python Net-SNMP bindings in the 5.7.3.
There are two ways around this:
Use the Python bindings in Net-SNMP 5.7.2
See this commit on our fork of the Net-SNMP Python library (only started yesterday so bear with us): https://github.com/fgimian/easysnmp/commit/fa86af977b563f65e7d70243752d48b94a8d5686 and replicate this in your download of Net-SNMP.

OSX Port Python Library Path? Cant find ctypes

I am trying to use an application that has a dependency of ctypes, but am getting this error:
$ python peach.py -t ~/Desktop/fuzz/wav/template.xml
] Peach 2.3.6 Runtime
] Copyright (c) Michael Eddington
Traceback (most recent call last):
File "peach.py", line 335, in <module>
from Peach.Engine import *
File "/opt/Peach-2.3.6/Peach/__init__.py", line 40, in <module>
import Publishers, Transformers
File "/opt/Peach-2.3.6/Peach/Publishers/__init__.py", line 37, in <module>
import file, sql, stdout, tcp, udp, com, process, http, icmp, raw, remote, dll, smtp
File "/opt/Peach-2.3.6/Peach/Publishers/file.py", line 37, in <module>
from Peach.Engine.engine import Engine
File "/opt/Peach-2.3.6/Peach/Engine/engine.py", line 835, in <module>
from Peach.Engine.state import StateEngine
File "/opt/Peach-2.3.6/Peach/Engine/state.py", line 38, in <module>
import sys, re, types, time, struct, ctypes
File "/opt/local/Library/Frameworks/Python.framework/Versions/2.5/lib/python2.5/ctypes/__init__.py", line 10, in <module>
from _ctypes import Union, Structure, Array
ImportError: No module named _ctypes
I have installed py-ctypes from ports, but it seems to only be a Python 2.4 version:
$ port contents py-ctypes
Port py-ctypes contains:
/opt/local/lib/python2.4/site-packages/_ctypes.so
/opt/local/lib/python2.4/site-packages/_ctypes_test.so
/opt/local/lib/python2.4/site-packages/ctypes/__init__.py
/opt/local/lib/python2.4/site-packages/ctypes/__init__.pyc
/opt/local/lib/python2.4/site-packages/ctypes/_endian.py
/opt/local/lib/python2.4/site-packages/ctypes/_endian.pyc
/opt/local/lib/python2.4/site-packages/ctypes/macholib/__init__.py
/opt/local/lib/python2.4/site-packages/ctypes/macholib/__init__.pyc
/opt/local/lib/python2.4/site-packages/ctypes/macholib/dyld.py
/opt/local/lib/python2.4/site-packages/ctypes/macholib/dyld.pyc
/opt/local/lib/python2.4/site-packages/ctypes/macholib/dylib.py
/opt/local/lib/python2.4/site-packages/ctypes/macholib/dylib.pyc
I then tried to run the application via python2.4, but it seems the application uses syntax that is only available in 2.5:
$ python2.4 peach.py -t ~/Desktop/fuzz/wav/template.xml
File "peach.py", line 498
finally:
^
SyntaxError: invalid syntax
My python install is also from OSX ports, and I noticed in the Peach application, it defines python as:
#!/usr/bin/python
Will that mess with anything if my default python executable points to my port installation (and I am running 'python peach.py')?
$ which python
/opt/local/bin/python
Is there any work around for this?
ctypes for python2.5?
Ability to add 2.4 libraries to 2.5 path?

A simple solution would be to use the native Python build that is included with Mac OS. This definitely works with the latest release of Mac OS X 10.6.4, which has Python 2.6.
Here is an example showing that '_ctypes' is being imported successfully:
mariah:~ joet3ch$ /usr/bin/python
Python 2.6.1 (r261:67515, Feb 11 2010, 00:51:29)
[GCC 4.2.1 (Apple Inc. build 5646)] on darwin
Type "help", "copyright", "credits" or "license" for more information.
>>> from _ctypes import Union, Structure, Array
>>>
If you have issues after this, try looking at the sys.path attribute to see which modules and versions are in your path.
Here is an example of viewing the contents of sys.path on a fresh Mac OS 10.6.4 build:
mariah:~ joet3ch$ /usr/bin/python
Python 2.6.1 (r261:67515, Feb 11 2010, 00:51:29)
[GCC 4.2.1 (Apple Inc. build 5646)] on darwin
Type "help", "copyright", "credits" or "license" for more information.
>>> import sys
>>> sys.path
['', '/System/Library/Frameworks/Python.framework/Versions/2.6/lib/python26.zip', '/System/Library/Frameworks/Python.framework/Versions/2.6/lib/python2.6', '/System/Library/Frameworks/Python.framework/Versions/2.6/lib/python2.6/plat-darwin', '/System/Library/Frameworks/Python.framework/Versions/2.6/lib/python2.6/plat-mac', '/System/Library/Frameworks/Python.framework/Versions/2.6/lib/python2.6/plat-mac/lib-scriptpackages', '/System/Library/Frameworks/Python.framework/Versions/2.6/Extras/lib/python', '/System/Library/Frameworks/Python.framework/Versions/2.6/lib/python2.6/lib-tk', '/System/Library/Frameworks/Python.framework/Versions/2.6/lib/python2.6/lib-old', '/System/Library/Frameworks/Python.framework/Versions/2.6/lib/python2.6/lib-dynload', '/Library/Python/2.6/site-packages', '/System/Library/Frameworks/Python.framework/Versions/2.6/Extras/lib/python/PyObjC', '/System/Library/Frameworks/Python.framework/Versions/2.6/Extras/lib/python/wx-2.8-mac-unicode']
>>>

ctypes is a standard Python library since version 2.5, so py-ctypes is not needed. The line at which you get an ImportError still exists in my 2.6.5 installation.
I do not own OSX, so my question is: does /opt/local/Library/Frameworks/Python.framework/Versions/2.5/lib/python2.5 belong to the standard installation of Python 2.5, or may this belong to a possibly broken installation of some framework?
In a running python shell, you could inspect the value of sys.path. Maybe there is some broken library that precedes the standard library.
The shebang line #!/usr/bin/python is interpreted by the OS if it is the first line of an executable script that is invoked directly like an ordinary program. In all other cases, this is just a comment. In particular, the line is ignored if you invoke the script as in python myscript.py or if it is imported by other Python code.

Python 2.5.2 and Solaris 8 (gcc 3.4.2) build issues

I'm trying to build python 2.5.2 on Solaris 8 using gcc 3.4.2. I can't see any immediate errors in the ./configure step but, once built and i enter the python shell doing an import time errors with :
Python 2.5.2 (r252:60911, Nov 21 2008, 18:45:42)
[GCC 3.4.2] on sunos5
Type "help", "copyright", "credits" or "license" for more information.
>>> import time
Traceback (most recent call last):
File "<stdin>", line 1, in <module>
ImportError: No module named time
What am i doing wrong? From what i can see with a cursory google is that there might be an error with libstdc++.so, but i can't find any hard details.
Any suggestions would be most welcome.
Many thanks,
Al.

The time module is not built by default in Python, if you build from a source distribution you need to explicitly enable all the modules you want to compile.
Open up Modules/Setup.dist in the python source tree and comment out the line which says:
#time timemodule.c
To enable the build of time module. Also remember that you need to recompile Python for this to take an effect.