add recent versions links to sidebar

The last five tags (that start with a number) are used as version
numbers and linked to. This updates the sphinx extension so that
every user of the theme gets this info automatically with no need
to update the conf.py on a per-project basis.

Change-Id: I9bf17872bd23bed3cab9b5e2349d615c7001cb66

oslosphinx/__init__.py

@@ -16,6 +16,7 @@
 import re
 import six
 from six.moves.urllib import parse
+import string
 import subprocess
 
 
@@ -42,6 +43,20 @@ def _guess_cgit_link():
 def _html_page_context(app, pagename, templatename, context, doctree):
     # Insert the cgit link into the template context.
     context['cgit_link'] = app.config.oslosphinx_cgit_link
+
+    git_cmd = ["git", "tag"]
+    try:
+        raw_version_list = subprocess.Popen(
+            git_cmd, stdout=subprocess.PIPE).communicate()[0]
+    except OSError:
+        app.warn('Cannot get tags from git repository. '
+                 'Not setting "other_versions".')
+        raw_version_list = ''
+
+    # grab last five that start with a number and reverse the order
+    other_versions = [t for t in raw_version_list.split('\n')
+                      if t and t[0] in string.digits][:-6:-1]
+    context['other_versions'] = other_versions
     return None
 
 

oslosphinx/theme/openstack/layout.html

@@ -30,6 +30,16 @@ <h4>{{ _('Next topic') }}</h4>
                                   title="{{ _('next chapter') }}">{{ next.title }}</a></p>
           {%- endif %}
           {%- endblock %}
+          {%- block otherversions %}
+            {%- if other_versions %}
+              <h3>{{ _('Other Versions') }}</h3>
+              <ul class="this-page-menu">
+              {%- for ver in other_versions: %}
+                  <li><a href="/{{ver}}" rel="nofollow">{{ ver }}</a></li>
+              {%- endfor %}
+              </ul>
+            {%- endif %}
+          {%- endblock %}
           {%- block projectsource %}
             {%- if cgit_link %}
             <h3>{{ _('Project Source') }}</h3>