Add uWSGI support

This patch implements uWSGI support for ironic API service.
ironic/api/app.wsgi is deprecated in favor of pbr generated
ironic-api-wsgi

Co-Authored-By: anascko <ovoshchana@mirantis.com>

Change-Id: Ieb68c1042e31b77f9a549fd90afe31a65008deca
Closes-Bug: #1719260
Closes-Bug: #1668966

doc/source/install/include/configure-ironic-api-mod_wsgi.rst

@@ -43,8 +43,9 @@ Bare Metal service comes with an example file for configuring the
       ``APACHE_RUN_GROUP`` directives to set the user and group values to
       an appropriate user on your server.
 
-   #. Modify the ``WSGIScriptAlias`` directive to point to the
-      ``ironic/api/app.wsgi`` script.
+   #. Modify the ``WSGIScriptAlias`` directive to point to the automatically
+      generated ``ironic-api-wsgi`` script that is located in `IRONIC_BIN`
+      directory.
 
    #. Modify the ``Directory`` directive to set the path to the Ironic API code.
 
@@ -68,5 +69,5 @@ Bare Metal service comes with an example file for configuring the
         sudo systemctl reload apache2
 
 .. note::
-   The file ``ironic/api/app.wsgi`` is installed with the rest of the Bare Metal
-   service application code, and should not need to be modified.
+   The file ``ironic-api-wsgi`` is automatically generated by pbr and is
+   available in `IRONIC_BIN` directory. It should not be modified.

etc/apache2/ironic

@@ -12,13 +12,14 @@
 
 # This is an example Apache2 configuration file for using the
 # Ironic API through mod_wsgi.  This version assumes you are
-# running devstack to configure the software.
+# running devstack to configure the software, and PBR has generated
+# and installed the ironic-api-wsgi script while installing ironic.
 
 Listen 6385
 
 <VirtualHost *:6385>
     WSGIDaemonProcess ironic user=stack group=stack threads=10 display-name=%{GROUP}
-    WSGIScriptAlias / /opt/stack/ironic/ironic/api/app.wsgi
+    WSGIScriptAlias / /usr/local/bin/ironic-api-wsgi
 
     SetEnv APACHE_RUN_USER stack
     SetEnv APACHE_RUN_GROUP stack

ironic/api/app.wsgi

@@ -16,24 +16,6 @@
 Use this file for deploying the API service under Apache2 mod_wsgi.
 """
 
-import sys
+from ironic.api import wsgi
 
-from oslo_config import cfg
-import oslo_i18n as i18n
-from oslo_log import log
-
-from ironic.api import app
-from ironic.common import service
-
-
-CONF = cfg.CONF
-
-i18n.install('ironic')
-
-service.prepare_service(sys.argv)
-
-LOG = log.getLogger(__name__)
-LOG.debug("Configuration:")
-CONF.log_opt_values(LOG, log.DEBUG)
-
-application = app.VersionSelectorApplication()
+application = wsgi.initialize_wsgi_app(show_deprecated=True)

ironic/api/wsgi.py

@@ -0,0 +1,41 @@
+# 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 script for Ironic API, installed by pbr."""
+
+import sys
+
+from oslo_config import cfg
+import oslo_i18n as i18n
+from oslo_log import log
+
+from ironic.api import app
+from ironic.common import service
+
+
+CONF = cfg.CONF
+LOG = log.getLogger(__name__)
+
+
+def initialize_wsgi_app(show_deprecated=False):
+    i18n.install('ironic')
+
+    service.prepare_service(sys.argv)
+
+    LOG.debug("Configuration:")
+    CONF.log_opt_values(LOG, log.DEBUG)
+
+    if show_deprecated:
+        LOG.warning("Using ironic/api/app.wsgi is deprecated and it will "
+                    "be removed in Rocky release. Please use automatically "
+                    "generated ironic-api-wsgi instead.")
+
+    return app.VersionSelectorApplication()

releasenotes/notes/wsgi-applications-5d36cf2a8885a56d.yaml

@@ -0,0 +1,10 @@
+---
+upgrade:
+  - An Ironic API WSGI application script ``ironic-api-wsgi`` is now available.
+    It is auto-generated by ``pbr`` and allows to run the API service
+    using WSGI server (for example Nginx and uWSGI or Apache with mod_wsgi).
+deprecations:
+  - Using ``ironic/api/app.wsgi`` script is deprecated and it will be removed
+    in Rocky release.
+    Please switch to automatically generated ``ironic-api-wsgi`` script
+    instead.

setup.cfg

@@ -44,6 +44,9 @@ console_scripts =
     ironic-conductor = ironic.cmd.conductor:main
     ironic-rootwrap = oslo_rootwrap.cmd:main
 
+wsgi_scripts =
+    ironic-api-wsgi = ironic.api.wsgi:initialize_wsgi_app
+
 ironic.dhcp =
     neutron = ironic.dhcp.neutron:NeutronDHCPApi
     none = ironic.dhcp.none:NoneDHCPApi