sysconfig⌗

The process of bundling Python code into a format that eases distribution and sharing. First up, I find it helps to get a concrete understanding of how the specific python distro I’m working with is configured, of paricular interest are the various system paths that will be visited for package dependencies. The built-in sysconfig module neatly manages and surfaces this information.

python -m sysconfig

On a Windows system:

PS C:\Users\ben\git\brightsnakes> python -m sysconfig
Platform: "win-amd64"
Python version: "3.11"
Current installation scheme: "nt"

Paths:
        data = "C:\Python311"
        include = "C:\Python311\Include"
        platinclude = "C:\Python311\Include"
        platlib = "C:\Python311\Lib\site-packages"
        platstdlib = "C:\Python311\Lib"
        purelib = "C:\Python311\Lib\site-packages"
        scripts = "C:\Python311\Scripts"
        stdlib = "C:\Python311\Lib"
...

On a Linux system:

$ python3 -m sysconfig
Platform: "linux-x86_64"
Python version: "3.10"
Current installation scheme: "posix_local"

Paths:
        data = "/usr/local"
        include = "/usr/include/python3.10"
        platinclude = "/usr/include/python3.10"
        platlib = "/usr/local/lib/python3.10/dist-packages"
        platstdlib = "/usr/lib/python3.10"
        purelib = "/usr/local/lib/python3.10/dist-packages"
        scripts = "/usr/local/bin"
        stdlib = "/usr/lib/python3.10"
...

On a Linux system under a virtualenv:

$ poetry run python3 -m sysconfig
Platform: "linux-x86_64"
Python version: "3.11"
Current installation scheme: "venv"

Paths:
        data = "/home/bms/.cache/pypoetry/virtualenvs/brightsnakes-u3bhK9-x-py3.11"
        include = "/usr/include/python3.11"
        platinclude = "/usr/include/python3.11"
        platlib = "/home/bms/.cache/pypoetry/virtualenvs/brightsnakes-u3bhK9-x-py3.11/lib/python3.11/site-packages"
        platstdlib = "/home/bms/.cache/pypoetry/virtualenvs/brightsnakes-u3bhK9-x-py3.11/lib/python3.11"
        purelib = "/home/bms/.cache/pypoetry/virtualenvs/brightsnakes-u3bhK9-x-py3.11/lib/python3.11/site-packages"
        scripts = "/home/bms/.cache/pypoetry/virtualenvs/brightsnakes-u3bhK9-x-py3.11/bin"
        stdlib = "/usr/lib/python3.11"

TODO: how to add custom package paths, using env vars, or sysconfig directly

Version number⌗

There’s several ways to approach managing a single source of truth version number for a package, such as keeping a VERSION text file and having setup.py read it, or abandon keeping a version in your repo at all and instead infer this from Git using setuptools_scm, or in the case of poetry the poetry-dynamic-versioning[plugin] plugin.

Project Structure⌗

A typical Python package consists of a directory (aka package) containing an __init__.py other Python source files. The __init__.py file is executed when the package is imported, and it’s often left empty but must exist in order for Python to recognise the directory as a standard package.

Setup Script⌗

The setup script (setup.py or pyproject.toml for recent versions) specifies metadata about the package like its name, version, author, and dependencies. It also instructs the packaging tools on how to build the package.

Distribution Archives⌗

Once the package and setup script are prepared, you can use tools like setuptools and wheel to create distribution archives (like .tar.gz or .whl files). These archives contain everything needed to install the package, including the package code and the setup script.

Distribution⌗

Finally, you can distribute the package by uploading the distribution archives to the Python Package Index (PyPI), a public repository of software for the Python programming language. Users can then install your package using pip, the standard package installer for Python.

Poetry⌗ 

poetry self add "poetry-dynamic-versioning[plugin]"
poetry source add --priority=supplemental private http://localhost:8080/simple/
poetry publish --repository private