Add samples to serve API through Apache mod_wsgi

The default API service (ironic.cmd.api) uses the wsgiref library.

Some deployers may want to serve the API through apache/httpd instead.

This patch adds application hooks to use with mod_wsgi, and a sample
apache2 config file to demonstrate its use with debian-based distros.

Change-Id: I44cd8e0941c350a6e5c16cf2d068c3e8d684ab47
Related-bug: #1279206

etc/apache2/ironic

@@ -0,0 +1,37 @@
+# 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 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.
+
+Listen 6385
+
+<VirtualHost *:6385>
+    WSGIDaemonProcess ironic user=stack group=stack threads=10
+    WSGIScriptAlias / /opt/stack/ironic/ironic/api/app.wsgi
+
+    SetEnv APACHE_RUN_USER stack
+    SetEnv APACHE_RUN_GROUP stack
+    WSGIProcessGroup ironic
+
+    ErrorLog /var/log/apache2/ironic_error.log
+    LogLevel info
+    CustomLog /var/log/apache2/ironic_access.log combined
+
+    <Directory /opt/stack/ironic/ironic/api>
+        WSGIProcessGroup ironic
+        WSGIApplicationGroup %{GLOBAL}
+        AllowOverride All
+        Require all granted
+    </Directory>
+</VirtualHost>

ironic/api/app.wsgi

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+# -*- mode: python -*-
+# -*- encoding: utf-8 -*-
+#
+# 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.
+"""
+Use this file for deploying the API service under Apache2 mod_wsgi.
+"""
+
+from ironic.api import app
+from ironic.common import service
+from ironic.openstack.common import gettextutils
+
+gettextutils.install('ironic')
+
+service.prepare_service([])
+
+application = app.VersionSelectorApplication()