Python dependencies

Python project dependencies management

Various combinations of tools:

Example of using venv+pip

1. You need to have global python3 installed first.

2. Create a new virtual environment in a local folder:

   cd repo-dir
   python3 -m venv .venv
   

3. Activate the env

   source .venv/bin/activate
   # For deactivation:
   # deactivate
   

4. Prepare pip

   python3 -m pip install --upgrade pip
   python3 -m pip --version
   

5. Using requirements.txt for package specification Check requirements file format.

   # requirements.txt
   numpy
   

6. Pip install depencies

   python -m pip install -r requirements.txt
   

Install and Uninstall

Packages installed by python setup.py install. [stackoverflow reference] Note: Avoid using python setup.py install use pip install . To uninstall, you need to remove all installed files manually, and also undo any other stuff that installation did manually. To record a list of installed files, you can use:

python setup.py install --record files.txt

Once you want to uninstall you can use xargs to do the removal:

xargs rm -rf < files.txt

Trouble Shooting

1. ModuleNotFound Error If you run “pip -V” or “pip list -v | grep -i " in the cli it will display where pip will install.

If you run ‘import sysconfig; print(sysconfig.get_paths()[“purelib”])’ it will show where python looks for packages.

If you know which interpreter you want to use, you can ensure an install will be going to the right place by running “python3 -m pip install mymodule”.

Sometime even the package is in the right path, python still can’t find it. It might due to wrong version of the package. Try to reinstall a right version.

(filix2) xxx$ pip list -v | grep piat
piat 2024.10.17 /home/colligo/miniforge3/envs/filix2/lib/python3.10/site-packages pip
(filix2) xxx$ python
Python 3.10.15 | packaged by conda-forge | (main, Oct 16 2024, 01:24:24) [GCC 13.3.0] on linux
Type "help", "copyright", "credits" or "license" for more information.
>>> import piat
Traceback (most recent call last):
  File "<stdin>", line 1, in <module>
ModuleNotFoundError: No module named 'piat'
>>> import sysconfig
>>> print(sysconfig.get_paths()["purelib"])
/home/colligo/miniforge3/envs/filix2/lib/python3.10/site-packages
>>> 

1. Pip install version error Check the available versions of a project:

   pip index versions <project-name>
   

   References

• Managing Python Dependencies
• Install packages in a virtual environment using pip and venv