config: set version in package module

Instead of 'setup.py'. It is a common practice and very convenient.

Author: glarrain

fd_gcp/__init__.py

@@ -28,3 +28,6 @@
   ``kms_crypto_key_resource_name`` (unlike ``kms_crypto_key_id``).
 
 """
+
+
+__version__ = '0.1.0'

setup.py

@@ -1,7 +1,24 @@
 #!/usr/bin/env python
+import os
+import re
+from typing import Sequence
+
 from setuptools import find_packages, setup
 
 
+def get_version(*file_paths: Sequence[str]) -> str:
+    filename = os.path.join(os.path.dirname(__file__), *file_paths)
+    version_file = open(filename).read()
+    version_match = re.search(
+        r"^__version__ = ['\"]([^'\"]*)['\"]", version_file, re.M)
+    if version_match:
+        return version_match.group(1)
+    raise RuntimeError('Unable to find version string.')
+
+
+version = get_version('fd_gcp', '__init__.py')
+
+
 with open('README.md') as readme_file:
     readme = readme_file.read()
 
@@ -24,9 +41,6 @@
     #   like 'coverage' or 'tox'.
 ]
 
-# TODO: extract from '__version__' in 'fd_gcp/__init__.py'.
-packages_version = '0.1.0'
-
 # note: the "typing information" of this project's packages is not made available to its users
 #   automatically; it needs to be packaged and distributed. The way to do so is fairly new and
 #   it is specified in PEP 561 - "Distributing and Packaging Type Information".
@@ -63,6 +77,6 @@
     test_suite='tests',
     tests_require=test_requirements,
     url='https://github.com/fyndata/gcp-utils-python',
-    version=packages_version,
+    version=version,
     zip_safe=False,
 )