Configure project name, version, release

This is currently done by pbr and we want to stop doing that. Start
overriding this via the 'builder-inited' event instead.

Change-Id: Ia2bdd815aac91bc191a4b965c4d07ea5aafa2f84

doc/source/conf.py

@@ -3,7 +3,6 @@
 # openstackdocstheme documentation build configuration file
 
 import openstackdocstheme
-from openstackdocstheme.version import version_info
 
 # Release name for PDF documents
 latex_custom_template = r"""
@@ -29,22 +28,9 @@ source_suffix = '.rst'
 # The master toctree document.
 master_doc = 'index'
 
-# "project" contains the name of the book, such as
-# 'security guide' or 'network guide'
-# It's used by the "log-a-bug" button on each page
-# and should ultimately be set automatically by the build process
-project = u'OpenStack Documentation Theme'
+# General information about the project.
 copyright = u'2015-2017, OpenStack Contributors'
 
-# The version info for the project you're documenting, acts as replacement for
-# |version| and |release|, also used in various other places throughout the
-# built documents.
-#
-# The full version, including alpha/beta/rc tags.
-release = version_info.release_string()
-# The short X.Y version.
-version = version_info.version_string()
-
 # List of patterns, relative to source directory, that match files and
 # directories to ignore when looking for source files.
 exclude_patterns = ['_build']

openstackdocstheme/ext.py

@@ -20,12 +20,14 @@ import os
 import subprocess
 
 import dulwich.repo
+from pbr import packaging
 from sphinx.ext import extlinks
 from sphinx.util import logging
 
 from openstackdocstheme import paths
 
 _series = None
+_project = None
 _giturl = 'https://git.openstack.org/cgit/{}/tree/{}'
 _html_context_data = None
 
@@ -123,6 +125,7 @@ def _get_series_name():
     global _series
     if _series is None:
         parser = configparser.ConfigParser()
+        # TODO(stephenfin): Should this be relative to some directory?
         parser.read('.gitreview')
         try:
             branch = parser.get('gerrit', 'defaultbranch')
@@ -143,11 +146,79 @@ def _setup_link_roles(app):
         app.add_role(role_name, extlinks.make_link_role(url, project_name))
 
 
+def _find_setup_cfg(srcdir):
+    """Find the 'setup.cfg' file, if it exists.
+
+    This assumes we're using 'doc/source' for documentation, but also allows
+    for single level 'doc' paths.
+    """
+    # TODO(stephenfin): Are we sure that this will always exist, e.g. for
+    # an sdist or wheel? Perhaps we should check for 'PKG-INFO' or
+    # 'METADATA' files, a la 'pbr.packaging._get_version_from_pkg_metadata'
+    for path in [
+            os.path.join(srcdir, os.pardir, 'setup.cfg'),
+            os.path.join(srcdir, os.pardir, os.pardir, 'setup.cfg')]:
+        if os.path.exists(path):
+            return path
+
+    return None
+
+
+def _get_project_name(srcdir):
+    """Return string name of project name, or None.
+
+    This assumes every project is using 'pbr' and, therefore, the metadata can
+    be extracted from 'setup.cfg'.
+
+    We don't rely on distutils/setuptools as we don't want to actually install
+    the package simply to build docs.
+    """
+    global _project
+    if _project is None:
+        parser = configparser.ConfigParser()
+
+        path = _find_setup_cfg(srcdir)
+        if not path or not parser.read(path):
+            logger.info('Could not find a setup.cfg to extract project name '
+                        'from')
+            return None
+
+        try:
+            project = parser.get('metadata', 'name')
+        except configparser.Error:
+            logger.info('Could not extract project name from setup.cfg')
+            return None
+        _project = project
+    return _project
+
+
 def _builder_inited(app):
     theme_dir = paths.get_html_theme_path()
     logger.info('Using openstackdocstheme Sphinx theme from %s' % theme_dir)
     _setup_link_roles(app)
 
+    # we only override configuration if the theme has been configured, meaning
+    # users are using these features
+    if app.config.html_theme != 'openstackdocs':
+        return
+
+    # TODO(stephenfin): Once Sphinx 1.8 is released, we should move the below
+    # to a 'config-inited' handler
+
+    project_name = _get_project_name(app.srcdir)
+    version = packaging.get_version(project_name)
+
+    # NOTE(stephenfin): Chances are that whatever's in 'conf.py' is probably
+    # wrong/outdated so, if we can, we intentionally overwrite it...
+    if project_name:
+        app.config.project = project_name
+
+    # ...except for version/release which, if blank, should remain that way to
+    # cater for unversioned documents
+    if app.config.version != '':
+        app.config.version = version
+        app.config.release = version
+
 
 def setup(app):
     logger.info('connecting events for openstackdocstheme')

releasenotes/notes/autoconfigure-settings-7083fdeeb121da89.yaml

@@ -0,0 +1,14 @@
+---
+features:
+  - |
+    The following configuration variables, normally defined in ``conf.py``,
+    can now be configured automatically.
+
+    - ``project``
+    - ``version``
+    - ``release``
+
+    It is not necessary to retain any configuration in ``conf.py`` and, in most
+    cases, such configuration will be ignored. The sole exceptions to this rule
+    are ``version`` and ``release`` which, if set to ``''`` will not be
+    overridden. This allows for unversioned documentation.