Add new keystone.wsgi module

This allows deployment tooling to easily switch from passing a binary
path to passing a Python module path. We'll use it shortly.

Change-Id: I36bb9ab43c3263b5064f35f4fc550722a0e83279

doc/source/conf.py

@@ -58,6 +58,7 @@ apidoc_excluded_paths = [
     'tests/*',
     'tests',
     'test',
+    'wsgi',
     # TODO(gmann): with new release of SQLAlchemy(1.4.27) TypeDecorator used
     # in common/sql/core.py file started failing. Remove this oncethe issue of
     # TypeDecorator is fixed.

httpd/keystone-uwsgi-admin.ini

@@ -1,5 +1,5 @@
 [uwsgi]
-wsgi-file = /usr/local/bin/keystone-wsgi-admin
+module = keystone.wsgi.api:application
 
 # Versions of mod_proxy_uwsgi>=2.0.6 should use a UNIX socket, see
 # http://uwsgi-docs.readthedocs.org/en/latest/Apache.html#mod-proxy-uwsgi

httpd/keystone-uwsgi-public.ini

@@ -1,5 +1,5 @@
 [uwsgi]
-wsgi-file = /usr/local/bin/keystone-wsgi-public
+module = keystone.wsgi.api:application
 
 # Versions of mod_proxy_uwsgi>=2.0.6 should use a UNIX socket, see
 # http://uwsgi-docs.readthedocs.org/en/latest/Apache.html#mod-proxy-uwsgi

keystone/wsgi/api.py

@@ -0,0 +1,22 @@
+# 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.
+
+"""WSGI application entry-point for Keystone API."""
+
+import threading
+
+from keystone.server import wsgi
+
+application = None
+with threading.Lock():
+    if application is None:
+        application = wsgi.initialize_public_application()

releasenotes/notes/add-keystone-wsgi-module-afae3f86df07eca9.yaml

@@ -0,0 +1,22 @@
+---
+features:
+  - |
+    A new module, ``keystone.wsgi``, has been added as a place to gather WSGI
+    ``application`` objects. This is intended to ease deployment by providing
+    a consistent location for these objects. For example, if using uWSGI then
+    instead of:
+
+    .. code-block:: ini
+
+        [uwsgi]
+        wsgi-file = /bin/keystone-wsgi-public
+
+    You can now use:
+
+    .. code-block:: ini
+
+        [uwsgi]
+        module = keystone.wsgi.api:application
+
+    This also simplifies deployment with other WSGI servers that expect module
+    paths such as gunicorn.