pdm 0.2.0

Python Development Master

PDM - Python Development Master

A modern Python package manager with PEP 582 support. 中文版本说明

What is PDM?

PDM is meant to be a next generation Python package management tool. It is originally built for personal interest. If you feel you are going well with Pipenv or Poetry and don't want to introduce another package manager, just stick to it. But if you are missing something that is not present in those tools, you can probably find some goodness in pdm.

Highlights of features

• PEP 582 local package installer and runner, no virtualenv involved at all.
• Simple and relatively fast dependency resolver, mainly for large binary distributions.
• A PEP 517 build backend.

Why not virtualenv?

Now the majority of Python packaging tools also act as virtualenv managers. It is for the benifit of isolating project environments. But things will get tricky when it comes to nested venvs: One installs the virtualenv manager using a venv capsulated Python, and create more venvs using the tool which is based on a capsulated Python. One day a minor release of Python out and one has to check all those venvs and upgrade them if required.

While PEP 582, in the other hand, introduce a way to decouple Python interpreter with project environments. It is a relative new proposal and there are not many tools supporting it, among which there is pyflow, but it is written with Rust and can't get much help from the big Python community. Moreover, due to the same reason, it can't act as a PEP 517 backend.

Installation:

PDM requires python version 3.7 or higher.

It is recommended to install pdm in an isolated enviroment, with pipx.

$ pipx install pdm

Or you can install it under user site:

$ pip install --user pdm

Usage

python -m pdm --help should be a good guidance.

FAQ

1. What is put in __pypackages__?

PEP 582 is a draft proposal which still needs a lot of polishment, for instance, it doesn't mention how to manage CLI executables. PDM take the decision to put bin, include together with lib under __pypackage__/X.Y.

2. How to run CLI scripts in the local package directory?

The recommended way is to prefix your command with pdm run. It is also possible to run CLI scripts directly from the outside, the PDM's installer has already injected the package path to the sys.path in the entry script file.

3. What site-packages will be loaded when using PDM?

PDM first looks to __pypackages__ but will fall back to looking in site-packages. This is not entirely hermetic and could lead to some confusion around which packages are being used, though.

4. Can I relocate or move the __pypackages__ folder for deployment?

You'd better not. The packages installed inside __pypackages__ are OS dependent. Instead, you should keep pdm.lock in VCS and do pdm sync on the target environment to deploy.

Credits

This project is strongly inspired by pyflow and poetry.

License

This project is open sourced under MIT license, see the LICENSE file for more details.