Python does not find module installed with pipx [duplicate]

Question

Debian Stable wants me to install Python modules using pipx. So I do

pipx install auditwheel
pipx ensurepath
python3 -m pipx ensurepath
python3

Output:

Python 3.11.2 (main, Mar 13 2023, 12:18:29) [GCC 12.2.0] on linux
Type "help", "copyright", "credits" or "license" for more information.

And:

import auditwheel

Output:

Traceback (most recent call last):
  File "<stdin>", line 1, in <module>
ModuleNotFoundError: No module named 'auditwheel'

What am I doing wrong?

Answer 1

From Python 3.11 onward, Debian encourages the users to create a separate Python virtual environment to install Python packages.

Because Debian declares its Python install to be externally-managed, pip (and other installers) will refuse to install packages system-wide. Installation is only possible in virtual environments or separate Python installs.

This is because Python package installers (like pip) are unaware of the constraints that APT-managed packages have on libraries and versions. See PEP 668 for a full discussion of the problems that can occur when multiple installers operate on the same Python install.

Therefore, the optimal way is to create a virtual environment, say MyEnv, and install packages therein:

mkdir -p $HOME/.venvs  # Create a folder for all virtual environments
python3 -m venv $HOME/.venvs/MyEnv  # Create MyEnv

This will create a directory $HOME/.venvs/MyEnv with a configuration file pyvenv.cfg which includes some details for this virtual environment, such as the Python executable and Python version.

Verify the version of the Python in the virtual environment:

$HOME/.venvs/MyEnv/bin/python --version

The executables of the created virtual environment are found under $HOME/.venvs/MyEnv/bin.

To install a package into the virtual environment, use

$HOME/.venvs/MyEnv/bin/python -m pip install <some-package>

To 'activate' the virtual environment, i.e. adding its configuration variables into the shell environment, use

source $HOME/.venvs/MyEnv/bin/activate

Consult Python's guide to virtualenv and pip at Install packages in a virtual environment using pip and venv.

Answer 2

pipx is not exactly the same as pip.

pipx installs applications in an isolated environment. It will not help if you want to compile and import a module. You can use a virtual environment as AlQuemist suggests.