2. Usage: polyversion library

updated:21/11/2018 16:16:39
copyright:2018 JRC.C4(STU), European Commission (JRC)
license:MIT License

The python 2.7+ library needed by (sub-)projects managed by polyvers cmd to derive their version-ids on runtime from Git.

Specifically, the configuration file .polyvers.yaml is NOT read - you have to repeat any non-default configurations as function/method keywords when calling this API.

Here only a very rudimentary documentation is provided - consult polyvers documents provided in the link above.


Only this library is (permissive) MIT-licensed, so it can be freely vendorized by any program - the respective polyvers command-line tool is “copylefted” under EUPLv1.2.

2.1. Quickstart

There are 4 ways to use this library:
  • As a setuptools plugin;
  • through its Python-API (to dynamically version your project);
  • through its barebone cmdline tool: polyversion (installation required);
  • through the standalone executable wheel: bin/pvlib.run (no installation, but sources required; behaves identically to polyversion command).

2.1.1. setuptools usage

The polyversion library function as a setuptools “plugin”, and adds two new setup() keywords for deriving subproject versions from PKG-INFO or git tags (see polyversion.init_plugin_kw()):

  1. keyword: polyversion --> (bool | dict)

    When a dict, its keys roughly mimic those in polyversion(), and can be used like this:

    from setuptools import setup
        version=''              # omit (or None) to abort if cannot auto-version
        polyversion={           # dict or bool
            'mono_project': True, # false by default
            ...  # See `polyversion.init_plugin_kw()` for more keys.
        setup_requires=[..., 'polyversion'],
  2. keyword: polyversion_check_bdist_enabled --> bool

    When it is true, the bdist-check is enabled, and any bdist_* setup-commands (e.g. bdist_wheel) will abort if not run from engraved sources (ie from an release tag).

    To enable this check without editing the sources, add the following into your $CWD/setup.cfg file:

    polyversion_check_bdist_enabled = true

2.1.2. API usage

An API sample of using also polytime() from within your myproject.git/myproject/__init__.py file:

from polyversion import polyversion, polytime  # no hack, dependency already installed

__version__ = polyversion()  # project assumed equal to this module-name: 'myproject'
__updated__ = polytime()


Depending on your repo’s versioning scheme (eg you have a mono-project repo, with version-tags simply like vX.Y.Z), you must add in both invocations of polyversion.polyversion() above the kw-arg mono_project=True.

2.1.3. Console usage

The typical command-line usage of this library (assuming you don’t want to install the full blown polyvers command tool) is given below:

user@host:~/ $ polyversion --help
Describe the version of a *polyvers* projects from git tags.

    polyversion [PROJ-1] ...
    polyversion [-v | -V ]     # print my version information

user@host:~/ $ polyversion polyversion    # fails, not in a git repo
b'fatal: not a git repository (or any of the parent directories): .git\n'
  cmd: ['git', 'describe', '--match=cf-v*']
Traceback (most recent call last):
  File "/pyenv/site-packages/pvlib/polyversion/__main__.py", line 18, in main
  File "/pyenv/site-packages/pvlib/polyversion/__init__.py", line 340, in run
    res = polyversion(args[0], repo_path=os.curdir)
  File "/pyenv/site-packages/pvlib/polyversion/__init__.py", line 262, in polyversion
    pvtag = _my_run(cmd, cwd=repo_path)
  File "/pyenv/site-packages/pvlib/polyversion/__init__.py", line 106, in _my_run
    raise sbp.CalledProcessError(proc.returncode, cmd)
subprocess.CalledProcessError: Command '['git', 'describe', '--match=cf-v*']' returned non-zero exit status 128.

user@host:~/ $ cd polyvers.git
user@host:~/polyvers.git (dev) $ polyversion polyvers polyversion
polyvers: 0.0.2a10
polyversion: 0.0.2a9

2.1.4. Standalone wheel

Various ways to use the standalone wheel from bash (these will still work without having installed anything):

user@host:~/polyvers.git (master) $
user@host:~/polyvers.git (master) $ ./bin/pvlib.run polyversion
polyversion: 0.0.2a9
user@host:~/polyvers.git (master) $ python ./bin/pvlib.run --help
user@host:~/polyvers.git (master) $ python ./bin/pvlib.run -m polyversion  -v
version: 0.0.2a9
user@host:~/polyvers.git (master) $ PYTHONPATH=./bin/pvlib.run  python -m polyversion  -V
version: 0.0.2a9
updated: Thu, 24 May 2018 02:47:37 +0300

For the rest, consult the polyvers project: https://polyvers.readthedocs.io