Generate doc for versioned notifications

This commit adds a new sphinx extension that inspects the nova code
and adds information about the existing versioned notifications to
the nofitications devref. This way the devref is automatically kept
up to date with relevant information.

Partially-Implements: bp versioned-notification-api
Change-Id: If65d5d81e26cb2b4a9f57a8c7d37d3de310ebe00

1 files changed, 112 insertions, 0 deletions

diff --git a/doc/ext/versioned_notifications.py b/doc/ext/versioned_notifications.py
new file mode 100644
index 0000000000..5f7fe5ed18
--- /dev/null
+++ b/doc/ext/versioned_notifications.py
@@ -0,0 +1,112 @@
+# 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.
+
+"""
+This provides a sphinx extension able to list the implemented versioned
+notifications into the developer documentation.
+
+It is used via a single directive in the .rst file
+
+  .. versioned_notifications::
+
+"""
+
+from sphinx.util.compat import Directive
+from docutils import nodes
+
+from nova.objects import base
+from nova.objects import notification
+
+
+def full_name(cls):
+    return cls.__module__ + '.' + cls.__name__
+
+
+class VersionedNotificationDirective(Directive):
+
+    LINK_PREFIX = 'https://git.openstack.org/cgit/openstack/nova/plain/'
+    SAMPLE_ROOT = 'doc/notification_samples/'
+
+    def run(self):
+        notifications = self._collect_notifications()
+        return self._build_markup(notifications)
+
+    def _collect_notifications(self):
+        notifications = []
+        ovos = base.NovaObjectRegistry.obj_classes()
+        for name, cls in ovos.items():
+            cls = cls[0]
+            if (issubclass(cls, notification.NotificationBase) and
+                    cls != notification.NotificationBase):
+
+                payload_name = cls.fields['payload'].objname
+                payload_cls = ovos[payload_name][0]
+
+                notifications.append((full_name(cls), full_name(payload_cls),
+                                      cls.sample))
+        return notifications
+
+    def _build_markup(self, notifications):
+        content = []
+        cols = ['Notification class', 'Payload class', 'Sample file link']
+        table = nodes.table()
+        content.append(table)
+        group = nodes.tgroup(cols=len(cols))
+        table.append(group)
+
+        head = nodes.thead()
+        group.append(head)
+
+        for i in range(len(cols)):
+            group.append(nodes.colspec(colwidth=1))
+
+        body = nodes.tbody()
+        group.append(body)
+
+        # fill the table header
+        row = nodes.row()
+        body.append(row)
+        for col_name in cols:
+            col = nodes.entry()
+            row.append(col)
+            text = nodes.strong(text=col_name)
+            col.append(text)
+
+        # fill the table content, one notification per row
+        for name, payload, sample in notifications:
+            row = nodes.row()
+            body.append(row)
+            col = nodes.entry()
+            row.append(col)
+            text = nodes.literal(text=name)
+            col.append(text)
+
+            col = nodes.entry()
+            row.append(col)
+            text = nodes.literal(text=payload)
+            col.append(text)
+
+            col = nodes.entry()
+            row.append(col)
+            ref = nodes.reference(refuri=self.LINK_PREFIX +
+                                  self.SAMPLE_ROOT + sample)
+            txt = nodes.inline()
+            col.append(txt)
+            txt.append(ref)
+            ref.append(nodes.literal(text=sample))
+
+        return content
+
+
+def setup(app):
+    app.add_directive('versioned_notifications',
+                      VersionedNotificationDirective)