Getting Package Version at Runtime

Automatically setting your project’s version is all well and good, but you usually also want to expose that version at runtime, usually via a __version__ variable. There are three options for doing this:

Use the version() function from importlib.metadata to get your package’s version, like so:
```
from importlib.metadata import version

__version__ = version("mypackage")
```
Note that importlib.metadata was only added to Python in version 3.8. If you wish to support older Python versions, use the importlib-metadata backport available on PyPI for those versions, e.g.:
```
import sys

if sys.version_info >= (3, 8):
    from importlib.metadata import version
else:
    from importlib_metadata import version

__version__ = version("mypackage")
```
If relying on the backport, don’t forget to include importlib-metadata; python_version < "3.8" in your project’s install_requires!
Fill out the [tool.versioningit.write] subtable in pyproject.toml so that the project version will be written to a file in your Python package which you can then import or read. For example, if your package is named mypackage and is stored in a src/ directory, you can write the version to a Python file src/mypackage/_version.py like so:
```
[tool.versioningit.write]
file = "src/mypackage/_version.py"
```
Then, within mypackage/__init__.py, you can import the version like so:
```
from ._version import __version__
```
Alternatively, you can write the version to a text file, say, src/mypackage/VERSION:
```
[tool.versioningit.write]
file = "src/mypackage/VERSION"
```
and then read the version in at runtime with:
```
from pathlib import Path
__version__ = Path(__file__).with_name("VERSION").read_text().strip()
```
(New in version 1.1.0) Use the onbuild step and its custom hooks to create sdists & wheels in which some file has been modified to contain the line __version__ = "<project version>" or similar while leaving your repository’s contents alone.

Tip

Wondering which of write and onbuild is right for your project? See this table for a comparison:

	`write`	`onbuild`
Should affected file be under version control?	No	Yes
Affected file must already exist?	No	Yes
Modifies working tree? [1]	Yes	No
Run when installing in editable mode?	Yes	No