Single-source: There is only one truth

single-source helps to reduce the entropy in your Python project by keeping single source of truth.

The targets of this library are modern Python projects which want to have one source of truth for version, name and etc.

At the moment, the library provides the single point for a package version.

It supports Python 3.6+.

Quick start

# root_package/__init__.py
from pathlib import Path
from single_source import get_version

__version__ = get_version(__name__, Path(__file__).parent.parent)

Root of the problem

You use modern pyproject.toml and want to keep the version of your package here:

# pyproject.toml
[tool.poetry]
name = "modern-project"
version = "0.1.0"

Let's imagine the version of your package is required in some place of the code.

Since you need the version in your Python code, you may want to duplicate the version by putting it as a string variable to some python file:

# modern_project/__init__.py
__version__ = "0.1.0"

# modern_project/version.py
version = "0.1.0"

Then you realize you don't want to have the version in a python file and in pyproject.toml at the same time. It's harder to keep them consistent and easier to forget to bump both versions before release.

Also, you don't want to build the wheel by creating some script for auto incrementing the version in both places (and use it in your CI flow, for example). Instead you want use poetry version commands.

Installation

You can install single-source via pip

pip3 install single-source

or via poetry

poetry add single-source

The library also available as a conda package in conda-forge channel

conda install single-source --channel conda-forge

Advanced usage

Changing default value

If it's not possible to get the version from package metadata or there is no pyproject.toml get_version returns "" - empty string by default. You can change this value by providing a value as a default_return keyword argument.

from pathlib import Path
from single_source import get_version

path_to_pyproject_dir = Path(__file__).parent.parent
__version__ = get_version(__name__, path_to_pyproject_dir, default_return=None)

Raising an exception

You may want to raise an exception in case the version of the package has not been found.

from pathlib import Path
from single_source import get_version, VersionNotFoundError

path_to_pyproject_dir = Path(__file__).parent.parent
try:
    __version__ = get_version(__name__, path_to_pyproject_dir, fail=True)
except VersionNotFoundError:
    pass

Not only pyproject.toml

You can use single-source even if you still store the version of your library in setup.py or in any other utf-8 encoded text file.

First, try without custom regex, probably it can parse the version

If the default internal regex does not find the version in your file, the only thing you need to provide is a custom regex to get_version:

from single_source import get_version

custom_regex = r"\s*version\s*=\s*[\"']\s*([-.\w]{3,})\s*[\"']\s*"

path_to_file = "~/my-project/some_file_with_version.txt"
__version__ = get_version(__name__, path_to_file, version_regex=custom_regex)

Version must be in the first group () in the custom regex.

Contributing

Pull requests are welcome. For major changes, please open an issue first to discuss what you would like to change.

Please make sure to update tests as appropriate.

License

MIT