Develop Reference

Cannot install python packages due to missing site-packages folder on Linux

On Linux, every time I try to install a python package I get an error that the site-packages directory is missing. For example:
error: [Errno 2] No such file or directory: '/opt/python/cp39-cp39/Lib/site-packages/'
One simple solution is to just create the missing directory; however, this is not possible in certain instances. For example, when running python -m build, a venv with a random name is created to build the package in - therefore, I cannot create the site-package folder since there is no pause where I can modify the new venv.
I have tested this on multiple machines, and this issue also appears in GitHub hosted CI/CD runners. This is especially difficult to resolve in CI/CD pipelines because I have no control over additional venvs created by build, cibuildwheel and other PyPA tools.
This error occurs when I run pip install ., python -m build and several other pip commands that involve building wheel packages. The error always occurs while pip is building the wheel.
I would appreciate any suggestions!

What is the preferred way to develop a python package without using setup.py

I am developing a python package, and I don't want to have to keep running pip install . to reinstall my package every time I change something. Using the -e or --editable doesn't seem to work unless I have a setup.py file, nor does --no-use-pep517. I have a pyproject.toml instead, as is preferred nowadays if I am not mistaken. So, what is the preferred way to do this nowadays?
My package is just a CLI script, but it imports some functions from another file in the same directory called utils.py. When developing, I can't just run the script manually rfrom the terminal, because then I get name_of_package is not a package from the line
from name_of_package.utils import function, whereas If i just have
from utils import function, I can run the script from the terminal, but when I pip install it, it says there is no module named utils.
I did install poetry and installed my dependencies, ran poetry shell and then tried to run my script with poetry run /path/to/script.py, but I kept getting an error that my package wasn't a package.

If you want to keep using setuptools as "build back-end" then you can replace the setup.py script with a setup.cfg declarative configuration file and still be able to do "editable" installations (independently of whether or not you have a pyproject.toml file).
There is now PEP 660 which standardizes editable installations. The following tools have support for PEP 660:
PDM
Flit
Hatch
Poetry
On top of setuptools-based projects, all projects that use a PEP 660 build back-end should be installable as editable by pip (python -m pip install --editable .).

compile translation files when calling setup.py install

I'm developing a Flask application using Babel. Thanks to Distutils/Setuptools Integration, all the parameters of compile/extract/... functions are stored in setup.cfg and compiling the i18n files is as easy as
./setup.py compile_catalog
Great. Now I would like this to be done automatically when running
./setup.py install
In make's words, that would be letting install target depend on compile_catalog target.
The context
We store only translation (.po) files in the code repository. .gitignore excludes .mo and .pot files from being tracked.
When a developer pulls a new revision of the code, he runs
pip install -r requirements.txt
to update dependencies and install the project in development mode. Then, using above command line, he compiles the translation binary (.mo) files.
Is there a simple and recommended way to modify setup.py to do both operations in one step? Or am I trying to misuse setuptools?
Using a script that like this would work for development purposes:
#!/bin/sh
./setup.py compile_catalog
pip install -r requirements.txt
but I would like a solution that also works when the package is installed with usual setup.py install instructions, like if installed from PyPi.
Should I understand that setuptools are not meant to be used like this, and people distributing software compile their translation files either manually or using custom scripts when creating their archives, rather than relying on setup.py to compile them at installation time?
I didn't find many posts on the Internet addressing this. The ones I found involved running pybabel command line interface from a function in setup.py, which sounds like a shame as it misses the point of setuptools integration.

I think your demand is totally valid and I'm quite surprised that there seems to be no official guideline on how to accomplish this.
The project I working on now also went multilingual and this is what I did:
In setup.cfg, make appropriate entries so that compile_catalog can be run without options.
In setup.py, subclass the install command from setuptools:
setup.py:
from setuptools import setup
from setuptools.command.install import install
class InstallWithCompile(install):
def run(self):
from babel.messages.frontend import compile_catalog
compiler = compile_catalog(self.distribution)
option_dict = self.distribution.get_option_dict('compile_catalog')
compiler.domain = [option_dict['domain'][1]]
compiler.directory = option_dict['directory'][1]
compiler.run()
super().run()
Then, when calling setup(), register our InstallWithCompile command with the name "install" and make sure that the *.mo files will be included in the package:
setup(
...
cmdclass={
'install': InstallWithCompile,
},
...
package_data={'': ['locale/*/*/*.mo', 'locale/*/*/*.po']},
)
Since babel is used during the setup, you should add it as a setup dependency:
setup_requires=[
'babel',
],
Note that a package (here, babel) appearing in both setup_requires and install_requires won't be installed correctly using python setup.py install due to an issue in setuptools, but it works fine with pip install.

Why isn't UniCurses for Python working?

I'm trying to make my first UniCurses project with Python on OpenSUSE.
I put the import statement in my .py file, but when I tried to run it, it says the module is not there... So I downloaded UniCurses from the website, and the instructions say Unix's Python already has UniCurses. That's odd, but I continued. I put the downloaded unicurses.py into my project directory, and when I tried running my file, an error message says UniCurses is not compatible with my system, and that either my Python distribution is below v2.6 or my operating system is something other than Windows or a *nix. My Python is v2.7.8, and again, my OS is a Linux distro. Why is this happening, and what should I do?
Edit: It's worth noting that the regular curses supposedly doesn't work on my system either.

Answer by Sagar Rakshe from How to install Python package from GitHub:
To install Python package from github, you need to clone that repository.
git clone https://github.com/jkbr/httpie.git
Then just run the setup.py file from that directory,
sudo python setup.py install
If you have already downloaded the file you can skip the first step and just run the python setup.py install in the folder. (I don't think sudo is necessary for python)

Python setuptools install as editable

I am packaging a python app with setuptools, typically running python setup.py install And it packages everything into an egg and installs it.
The problem is I want it to be installed as editable, so I can go into site-packages and make changes to the app source code. I haven't yet found out how to do it yet.
On my previous work environment, running python setup.py install would copy the source folder to the site-packages, but this time it doesn't do it.

You can try:
python setup.py develop
like described here.