Use stevedore directive to document plugins.

Add directives to the documentation to bring in docstrings from the
plugins used by glance.

Change-Id: I06df808446c749588b719001e172721db6d43660

doc/source/artifact-types.rst

@@ -0,0 +1,21 @@
+..
+      Copyright 2015 OpenStack Foundation
+      All Rights Reserved.
+
+      Licensed under the Apache License, Version 2.0 (the "License"); you may
+      not use this file except in compliance with the License. You may obtain
+      a copy of the License at
+
+          http://www.apache.org/licenses/LICENSE-2.0
+
+      Unless required by applicable law or agreed to in writing, software
+      distributed under the License is distributed on an "AS IS" BASIS, WITHOUT
+      WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. See the
+      License for the specific language governing permissions and limitations
+      under the License.
+
+Glance Artifact Types
+=====================
+
+.. list-plugins:: glance.artifacts.types
+   :detailed:

doc/source/conf.py

@@ -47,6 +47,7 @@ extensions = ['sphinx.ext.coverage',
               'sphinx.ext.pngmath',
               'sphinx.ext.graphviz',
               'oslosphinx',
+              'stevedore.sphinxext',
               ]
 
 # Add any paths that contain templates here, relative to this directory.

doc/source/database_architecture.rst

@@ -188,3 +188,19 @@ of an *Image* object.
    :alt: Glance images DB schema
 
 .. centered:: Image 1. Glance images DB schema
+
+
+Glance Database Backends
+~~~~~~~~~~~~~~~~~~~~~~~~
+
+Migration Backends
+------------------
+
+.. list-plugins:: glance.database.migration_backend
+   :detailed:
+
+Metadata Backends
+-----------------
+
+.. list-plugins:: glance.database.metadata_backend
+   :detailed:

doc/source/flows.rst

@@ -0,0 +1,30 @@
+..
+      Copyright 2015 OpenStack Foundation
+      All Rights Reserved.
+
+      Licensed under the Apache License, Version 2.0 (the "License"); you may
+      not use this file except in compliance with the License. You may obtain
+      a copy of the License at
+
+          http://www.apache.org/licenses/LICENSE-2.0
+
+      Unless required by applicable law or agreed to in writing, software
+      distributed under the License is distributed on an "AS IS" BASIS, WITHOUT
+      WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. See the
+      License for the specific language governing permissions and limitations
+      under the License.
+
+Glance Flow Plugins
+===================
+
+Flows
+-----
+
+.. list-plugins:: glance.flows
+   :detailed:
+
+Import Flows
+------------
+
+.. list-plugins:: glance.flows.import
+   :detailed:

doc/source/image-location-strategy-modules.rst

@@ -0,0 +1,21 @@
+..
+      Copyright 2015 OpenStack Foundation
+      All Rights Reserved.
+
+      Licensed under the Apache License, Version 2.0 (the "License"); you may
+      not use this file except in compliance with the License. You may obtain
+      a copy of the License at
+
+          http://www.apache.org/licenses/LICENSE-2.0
+
+      Unless required by applicable law or agreed to in writing, software
+      distributed under the License is distributed on an "AS IS" BASIS, WITHOUT
+      WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. See the
+      License for the specific language governing permissions and limitations
+      under the License.
+
+Image Location Strategy Modules
+===============================
+
+.. list-plugins:: glance.common.image_location_strategy.modules
+   :detailed:

doc/source/index.rst

@@ -68,6 +68,9 @@ Installing/Configuring Glance
    configuring
    authentication
    policies
+   image-location-strategy-modules
+   artifact-types
+   flows
 
 Operating Glance
 ================

glance/async/flows/convert.py

@@ -100,6 +100,12 @@ class _Convert(task.Task):
 
 
 def get_flow(**kwargs):
+    """Return task flow for converting images to different formats.
+
+    :param task_id: Task ID.
+    :param task_type: Type of the task.
+    :param image_repo: Image repository used.
+    """
     task_id = kwargs.get('task_id')
     task_type = kwargs.get('task_type')
     image_repo = kwargs.get('image_repo')

glance/async/flows/introspect.py

@@ -76,6 +76,13 @@ class _Introspect(utils.OptionalTask):
 
 
 def get_flow(**kwargs):
+    """Return task flow for introspecting images to obtain metadata about the
+    image.
+
+    :param task_id: Task ID
+    :param task_type: Type of the task.
+    :param image_repo: Image repository used.
+    """
     task_id = kwargs.get('task_id')
     task_type = kwargs.get('task_type')
     image_repo = kwargs.get('image_repo')