Add sample config file to nova docs

This commit adds sample config file generation to the nova devref
using the oslo.config sphinxconfiggen module which was recently added.
This will generate a new sample config each time build sphinx is run.
This is then used on a new docs page where you can either view the file
in its entirety, or download the file. The sphinx module was added in
the oslo.config 2.3.0 release.

Change-Id: I6d9150d81c8204bee8f775021a854928671bdd02

.gitignore

@@ -39,3 +39,4 @@ nosetests.xml
 nova/tests/cover/*
 nova/vcsversion.py
 tools/conf/nova.conf*
+doc/source/_static/nova.conf.sample

doc/source/conf.py

@@ -34,8 +34,12 @@ extensions = ['sphinx.ext.autodoc',
               'oslosphinx',
               "ext.support_matrix",
               'sphinxcontrib.seqdiag',
+              'oslo_config.sphinxconfiggen',
               ]
 
+config_generator_config_file = '../../etc/nova/nova-config-generator.conf'
+sample_config_basename = '_static/nova'
+
 todo_include_todos = True
 
 # The suffix of source filenames.

doc/source/index.rst

@@ -180,6 +180,15 @@ Advanced testing and guides
     testing/libvirt-numa
     testing/serial-console
 
+Sample Configuration File
+-------------------------
+
+.. toctree::
+    :maxdepth: 1
+
+    sample_config
+
+
 Man Pages
 ----------
 

doc/source/sample_config.rst

@@ -0,0 +1,12 @@
+==========================
+Nova Configuration Options
+==========================
+
+The following is a sample Nova configuration for adaptation and use. It is
+auto-generated from Nova when this documentation is built, so
+if you are having issues with an option, please compare your version of
+Nova with the version of this documentation.
+
+The sample configuration can also be viewed in `file form <_static/nova.conf.sample>`_.
+
+.. literalinclude:: _static/nova.conf.sample