How to install local package

[the-sean-c]

Hi, I'm trying to locally install a package in the src folder. At the simplest, this would look something like the src/example_package that pdm makes by default when you run pdm init. However, if I try to install that package, using pdm add ./src/example_package/, then I get this error:

[RequirementError]: The local path 'src/example_package' is not installable.

This seems to me to be the way it should work based on the docs. What am I doing wrong?

[pawamoy]

There is no pyproject.toml in src/example_package, so no Python installation tool would know how to install it. If you want to list a local package as a dependency of your project, you can indeed use pdm add, but you have to point it at the root folder which contains pyproject.toml. Also, you don't need to add the current project as a dependency of itself! In your case I believe you can just run pdm install.

[the-sean-c]

Hmm. I tried pdm install, but it gave me [KeyError]: 'name'.

Instead, I deleted the project and started again with pdm init, this time when it asked "Is the project a library that is installable?", I said yes. now after pdm install pdm picks up the packages under src automatically. This is like poetry, which is what I expected to happen.

Looks like that solved it, thanks!

[Hopsakee]

I could still use some help here. I'm afraid I'm missing some very basic knowledge.

My projectfolder has this structure:

PDMtest/
    ├── src/
    │   └── __init__.py
    │   └── print_helper.py
    └── tests/
    │   └── runner_tests.py
    └── runner_root.py

runner_tests.py and runner_root.py both look like this:

from src import print_helper

print_helper.all_of_it()

Now. The file runner_tests.py gives an import error:

ModuleNotFoundError: No module named 'src'

While the file runner_root.py runs just fine.

Can someone explain what I'm missing?

I tried:

• After pdm init => "Is the project a library that is installable?", YES
• pdm add -e ./src
• pdm add ./src

And some other pdm add commands.

The 'pdm add' like commands give errors like this:

[PdmUsageError]: Cannot add editables to the default or optional dependency group

Or

[RequirementError]: The local path 'src' is not installable.

I also tried adding to my pyproject.toml

dependencies = [
    "file:///${PROJECT_ROOT}/src",
    ]

This gives the [RequirementError] when I do pdm install.

What does work is adding the src folder to my pythonpath like this in the runner_tests.py file:

import sys
import os
sys.path.insert(0, os.path.abspath(os.path.join(os.path.dirname(__file__), '..')))

But to me that looks like a workaround instead of a solution. Are there any more robust and pythonic PDM ways to use the code that is located in a folder from within a file that is itself located in another folder?

[pawamoy]

As mentioned above, you don't need to add the sources as a dependency of the project itself (it doesn't make sense anyway to try and add src as a dependency).

When using the src-layout, you are supposed to have this file tree:

project/
    src/
        your_package/
            __init__.py

You are missing your_package in your tree.

Surely you don't want to name your package "src", right 😄

Then, in your runner modules, import from your_package:

from your_package import print_helper

Finally, to run either of your runner scripts, use pdm run python runner_root.py, or pdm run python tests/runner_tests.py (but in the latter case I suppose you're rather using something like pytest, so that rather be pdm run pytest). PDM takes care of finding your package in src and putting it in PYTHONPATH/sys.path for you.

[pawamoy]

More info on src-layout vs. flat-layout: https://packaging.python.org/en/latest/discussions/src-layout-vs-flat-layout/.

[Hopsakee]

@pawamoy Thanks. This really helped, in combination with the earlier advise to pdm init with "installable library".

Indeed, I wasn't planning on naming my package 'src'. 😄 But the fact that I suggested that, in my attempt to make my example as simple as possible, already suggests I couldn't wrap my head around what I was doing exactly. 😆 Your reference to the src-layout vs flat-layout was very helpful. Thanks.

[pawamoy]

Glad I could help! The different layouts cause a lot of confusion, you're not the only one ^^