adding version.py

docs/version.py

@@ -0,0 +1,45 @@
+# Source: https://github.com/Changaco/version.py
+
+from os.path import dirname, isdir, join
+import re
+from subprocess import CalledProcessError, check_output
+
+
+PREFIX = ''
+
+tag_re = re.compile(r'\btag: %s([0-9][^,]*)\b' % PREFIX)
+version_re = re.compile('^Version: (.+)$', re.M)
+
+
+def get_version():
+    # Return the version if it has been injected into the file by git-archive
+    version = tag_re.search('$Format:%D$')
+    if version:
+        return version.group(1)
+
+    d = dirname(__file__)
+
+    if isdir(join(d, '.git')):
+        # Get the version using "git describe".
+        cmd = 'git describe --tags --match %s[0-9]* --dirty' % PREFIX
+        try:
+            version = check_output(cmd.split()).decode().strip()[len(PREFIX):]
+        except CalledProcessError:
+            raise RuntimeError('Unable to get version number from git tags')
+
+        # PEP 440 compatibility
+        if '-' in version:
+            if version.endswith('-dirty'):
+                raise RuntimeError('The working tree is dirty')
+            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())