Enable configfile autogeneration

This patch enables configfile autogeneration. It is triggered

* implicitly on every sphinx build
  output dir: doc/source/html/_static/nova_dpm.conf.sample
  for doc inclusion
* explicilty by tox -egenconfig
  output dir: etc/nova/nova_dpm.conf.sample
* explicitly by tox -edocs
  output dir: etc/nova/nova_dpm.conf.sample

In addition the return type of nova_dpm.conf.dpm.list_opts needed
to be changed to the default format (list of tuples).

Change-Id: Ib298b274f877d651dd846cac6525789c458da407
Closes-Bug: #1657701

.gitignore

@@ -57,3 +57,7 @@ ChangeLog
 
 # Files created by releasenotes build
 releasenotes/build
+
+# Ignore autogenerated config files
+etc/nova/nova_dpm.conf.sample
+doc/source/_static/nova_dpm.conf.sample

doc/source/conf.py

@@ -26,9 +26,14 @@ extensions = [
     'sphinx.ext.autodoc',
     #'sphinx.ext.intersphinx',
     'sphinxcontrib.seqdiag',
-    'oslosphinx'
+    'oslosphinx',
+    'oslo_config.sphinxconfiggen'
+
 ]
 
+config_generator_config_file = '../../etc/nova/nova-dpm-config-generator.conf'
+sample_config_basename = '_static/nova_dpm'
+
 # autodoc generation is a bit aggressive and a nuisance when doing heavy
 # text edit cycles.
 # execute "export SPHINX_DEBUG=1" in your terminal to disable

doc/source/index.rst

@@ -52,6 +52,7 @@ Contents:
     installation
     usage
     contributing
+    sample_config
 
 Specifications
 ==============

doc/source/sample_config.rst

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

etc/nova/nova-dpm-config-generator.conf

@@ -0,0 +1,4 @@
+[DEFAULT]
+output_file = etc/nova/nova_dpm.conf.sample
+wrap_width = 80
+namespace = nova_dpm

nova_dpm/conf/dpm.py

@@ -59,4 +59,4 @@ def register_opts(conf):
 
 
 def list_opts():
-    return {dpm_group: ALL_DPM_OPTS}
+    return [(dpm_group, ALL_DPM_OPTS)]

setup.cfg

@@ -52,3 +52,6 @@ all_files = 1
 build-dir = releasenotes/build
 source-dir = releasenotes/source
 
+[entry_points]
+oslo.config.opts =
+    nova_dpm = nova_dpm.conf.dpm:list_opts

tox.ini

@@ -4,6 +4,7 @@ envlist = py35,py34,py27,pep8
 skipsdist = True
 
 [testenv]
+usedevelop = True
 # NOTE(markus_z): We need the commands keyword, otherwise tox 2.5.0 throws an error.
 # See https://bugs.launchpad.net/charm-aodh/+bug/1642981 and
 # https://github.com/tox-dev/tox/issues/316
@@ -29,7 +30,9 @@ commands =
   coverage report
 
 [testenv:docs]
-commands = python setup.py build_sphinx
+commands =
+  python setup.py build_sphinx
+  oslo-config-generator --config-file=etc/nova/nova-dpm-config-generator.conf
 
 [testenv:debug]
 commands = oslo_debug_helper {posargs}
@@ -41,3 +44,6 @@ show-source = True
 ignore = E123,E125
 builtins = _
 exclude=.venv,.git,.tox,dist,doc,*lib/python*,*egg,build,.tmp
+
+[testenv:genconfig]
+commands = oslo-config-generator --config-file=etc/nova/nova-dpm-config-generator.conf