version.py

# This program is placed into the public domain.

"""
Gets the current version number.
If in a git repository, it is the current git tag.
Otherwise it is the one contained in the PKG-INFO file.

To use this script, simply import it in your setup.py file
and use the results of get_version() as your package version:

    from version import *

    setup(
        ...
        version=get_version(),
        ...
    )
"""

from __future__ import print_function

__all__ = ('get_version')

from os.path import dirname, isdir, join
import re
from subprocess import CalledProcessError, Popen, PIPE

try:
    from subprocess import check_output
except ImportError:
    def check_output(*popenargs, **kwargs):
        r"""Run command with arguments and return its output as a byte string.

        If the exit code was non-zero it raises a CalledProcessError.  The
        CalledProcessError object will have the return code in the returncode
        attribute and output in the output attribute.

        The arguments are the same as for the Popen constructor.  Example:

        >>> check_output(["ls", "-l", "/dev/null"])
        'crw-rw-rw- 1 root root 1, 3 Oct 18  2007 /dev/null\n'

        The stdout argument is not allowed as it is used internally.
        To capture standard error in the result, use stderr=STDOUT.

        >>> check_output(["/bin/sh", "-c",
        ...               "ls -l non_existent_file ; exit 0"],
        ...              stderr=STDOUT)
        'ls: non_existent_file: No such file or directory\n'
        """
        if 'stdout' in kwargs:
            raise ValueError('stdout argument not allowed, '
                             'it will be overridden.')
        process = Popen(stdout=PIPE, *popenargs, **kwargs)
        output, unused_err = process.communicate()
        retcode = process.poll()
        if retcode:
            cmd = kwargs.get("args")
            if cmd is None:
                cmd = popenargs[0]
            raise CalledProcessError(retcode, cmd, output=output)
        return output

version_re = re.compile('^Version: (.+)$', re.M)


def get_version():
    d = dirname(__file__)

    if isdir(join(d, '.git')):
        # Get the version using "git describe".
        cmd = 'git describe --tags --match [0-9]*'.split()
        try:
            version = check_output(cmd).decode().strip()
        except CalledProcessError:
            print('Unable to get version number from git tags')
            exit(1)

        # PEP 386 compatibility
        if '-' in version:
            version = '.post'.join(version.split('-')[:2])

    else:
        # Extract the version from the PKG-INFO file.
        with open(join(d, 'PKG-INFO')) as f:
            version = version_re.search(f.read()).group(1)

    return version


if __name__ == '__main__':
    print(get_version())