Add wsgi module to Designate and remove wsgi script

Changes in python packaging tooling mean that the wsgi_scripts
functionality via PBR may not longer function.

This patch switches Designate from using the PBR wsgi_scripts method to
using a new wsgi module that provides the same behavior as the generated
wsgi scripts provided.

A related devstack patch enables devstack to setup uWSGI to use the new
module path instead of the generated wsgi scripts.

This also aligns Designate to a new proposed OpenStack goal[1].

[1] https://review.opendev.org/c/openstack/governance/+/902807

In order to make the CI work, this patch was merged with:

zuul: Drop centos9 and make grenade non-voting

The requirements repo has dropped upper-constraints for python3.9, so
the centos9-based jobs are no longer working on master, let's drop them.

Also the grenade jobs are broken due to the referenced bug, make them
temporarily non-voting, so that we can merge the fix[0] on master first,
backport it, and then re-enable them.

[0] https://review.opendev.org/c/openstack/designate/+/902846

Related-Bug: 2109577
Depends-On: https://review.opendev.org/c/openstack/devstack/+/902758
Change-Id: If90056ae1de4a6a3557fc870497e6233088bfb02

.zuul.yaml

@@ -51,16 +51,6 @@
     post-run: playbooks/designate-bind9/post.yaml
     parent: designate-base
 
-- job:
-    name: designate-bind9-centos9stream-fips
-    parent: designate-bind9
-    nodeset: devstack-single-node-centos-9-stream
-    description: |
-      Functional testing for a FIPS enabled Centos 9 stream system
-    pre-run: playbooks/enable-fips.yaml
-    vars:
-      nslookup_target: 'opendev.org'
-
 - job:
     name: designate-bind9-keystone-old-default-roles
     post-run: playbooks/designate-bind9/post.yaml
@@ -83,15 +73,6 @@
             enforce_scope:
               designate: False
 
-- job:
-    name: designate-bind9-centos-9-stream
-    parent: designate-bind9
-    nodeset: devstack-single-node-centos-9-stream
-    vars:
-      devstack_localrc:
-        DESIGNATE_COORDINATION_URL: "etcd3+http://{{ hostvars['controller']['nodepool']['private_ipv4'] }}:2379?api_version=v3"
-
-
 - job:
     name: designate-bind9-catalog-zones
     parent: designate-bind9
@@ -218,14 +199,11 @@
     check:
       jobs:
         - designate-bind9
-        - designate-bind9-centos9stream-fips:
-            voting: false
-        - designate-bind9-centos-9-stream:
-            voting: false
         - designate-bind9-keystone-old-default-roles
         - designate-pdns4
         - designate-grenade-bind9
-        - designate-grenade-pdns4
+        - designate-grenade-pdns4:
+            voting: false
         - designate-grenade-bind9-skip-level
         - designate-grenade-pdns4-skip-level
         - designate-ipv6-only-pdns4
@@ -236,7 +214,6 @@
         - designate-bind9
         - designate-bind9-keystone-old-default-roles
         - designate-pdns4
-        - designate-grenade-pdns4
         - designate-grenade-pdns4-skip-level
         - designate-ipv6-only-pdns4
         - designate-ipv6-only-bind9

designate/wsgi/api.py

@@ -0,0 +1,24 @@
+# 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 the Designate API."""
+
+import threading
+
+from designate.api import wsgi
+
+application = None
+
+lock = threading.Lock()
+with lock:
+    if application is None:
+        application = wsgi.init_application()

devstack/lib/wsgi

@@ -1,7 +1,7 @@
 #!/usr/bin/env bash
 
 function designate_configure_uwsgi {
-    write_uwsgi_config "$DESIGNATE_UWSGI_CONF" "$DESIGNATE_UWSGI" "/dns"
+    write_uwsgi_config "$DESIGNATE_UWSGI_CONF" "$DESIGNATE_UWSGI" "/dns" "" "designate-api-wsgi"
 
     # We are using the http transport to work around an issue with
     # broken connections when using the uwsgi protocol of a local socket

devstack/settings

@@ -60,7 +60,7 @@ DESIGNATE_ROOTWRAP_CONF=$DESIGNATE_CONF_DIR/rootwrap.conf
 DESIGNATE_APIPASTE_CONF=$DESIGNATE_CONF_DIR/api-paste.ini
 DESIGNATE_PLUGINS=$DESIGNATE_DIR/devstack/designate_plugins
 
-DESIGNATE_UWSGI=$DESIGNATE_BIN_DIR/designate-api-wsgi
+DESIGNATE_UWSGI=designate.wsgi.api:application
 DESIGNATE_UWSGI_CONF=$DESIGNATE_CONF_DIR/designate-api-uwsgi.ini
 
 # Default repositories

releasenotes/notes/remove-wsgi-scripts-d848069ac50cf062.yaml

@@ -0,0 +1,29 @@
+---
+features:
+  - |
+    A new module, ``designate.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/designate-api-wsgi
+
+    You can now use:
+
+    .. code-block:: ini
+
+        [uwsgi]
+        module = designate.wsgi.api:application
+
+    This also simplifies deployment with other WSGI servers that expect module
+    paths such as gunicorn.
+upgrade:
+  - |
+    The WSGI script ``designate-api-wsgi`` has been removed. Deployment tooling
+    should instead reference the Python module path for the wsgi module in
+    Designate, ``designate.wsgi.api:application`` if their chosen WSGI server
+    supports this (gunicorn, uWSGI, etc.) or implement a .wsgi script
+    themselves if not (mod_wsgi).

setup.cfg

@@ -119,6 +119,3 @@ designate.heartbeat_emitter =
 designate.notification.plugin =
   default = designate.notifications:Default
   audit = designate.notifications:Audit
-
-wsgi_scripts =
-    designate-api-wsgi = designate.api.wsgi:init_application