build: Invert version fetching.

A lot of systems expect the version number to be in the package metadata
so make that the source of truth and update the code to pull the version
variable from there instead of the other way around.

Author: feanil

backend/docs/conf.py

@@ -18,28 +18,13 @@
 from subprocess import check_call
 
 from django import setup as django_setup
-
-
-def get_version(*file_paths):
-    """
-    Extract the version string from the file.
-
-    Input:
-     - file_paths: relative path fragments to file with
-                   version string
-    """
-    filename = os.path.join(os.path.dirname(__file__), *file_paths)
-    version_file = open(filename, encoding="utf8").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.')
+from importlib.metadata import version as get_version
 
 
 REPO_ROOT = os.path.dirname(os.path.dirname(os.path.abspath(__file__)))
 sys.path.append(REPO_ROOT)
 
-VERSION = get_version('../sample_plugin', '__init__.py')
+VERSION = get_version('openedx-sample-plugin')
 # Configure Django for autodoc usage
 os.environ['DJANGO_SETTINGS_MODULE'] = 'test_settings'
 django_setup()

backend/pyproject.toml

@@ -7,6 +7,7 @@ name = "openedx-sample-plugin"
 description = "A sample backend plugin for the Open edX Platform"
 requires-python = ">=3.11"
 license="Apache-2.0"
+version = "0.1.0"
 authors = [
     {name = "Open edX Project", email = "[email protected]"},
 ]
@@ -24,7 +25,7 @@ keywords= [
     "edx",
 ]
 
-dynamic = ["version", "readme", "dependencies"]
+dynamic = ["readme", "dependencies"]
 
 [project.entry-points."lms.djangoapp"]
 sample_plugin = "sample_plugin.apps:SamplePluginConfig"
@@ -37,7 +38,6 @@ Homepage = "https://openedx.org/openedx/sample-plugin"
 Repository = "https://openedx.org/openedx/sample-plugin"
 
 [tool.setuptools.dynamic]
-version = {attr = "sample_plugin.__version__"}
 readme = {file = ["README.rst", "CHANGELOG.rst"]}
 dependencies = {file = "requirements/base.in"}
 

backend/sample_plugin/__init__.py

@@ -2,4 +2,8 @@
 A sample backend plugin for the Open edX Platform.
 """
 
-__version__ = "0.1.0"
+from importlib.metadata import version as get_version
+
+# The name of the package is `openedx-sample-plugin` but __package__ is `sample_plugin` so we hardcode the name of the
+# package here so that the version fetching works correctly.  A lot of examples will show using `__package__`.
+__version__ = get_version('openedx-sample-plugin')