Add support to have Senlin API run under Apache

Add scripts for running Senlin API service under apache2, will add
related devstack support in another patch.

Implements bp: run-senlin-api-under-apache

Change-Id: I18872546a653c5de26360b6289dd1f5886c4a2b7

senlin/api/common/wsgi.py

@@ -673,7 +673,13 @@ class Resource(object):
             # Attach openstack-api-version header
             if hasattr(response, 'headers'):
                 for hdr, val in response.headers.items():
-                    response.headers[hdr] = six.text_type(val)
+                    # Note(lvdongbing): Ensure header is a python 2 or 3
+                    # native string (thus not unicode in python 2 but stay
+                    # a string in python 3). Because mod-wsgi checks that
+                    # response header values are what's described as
+                    # "native strings". This means whatever `str` is in
+                    # either python 2 or 3, but never `unicode`.
+                    response.headers[hdr] = str(val)
                 ver = request.version_request
                 if not ver.is_null():
                     ver_res = ' '.join(['clustering', str(ver)])

senlin/cmd/api_wsgi.py

@@ -0,0 +1,41 @@
+#!/usr/bin/env python
+#
+#    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 senlin-api.
+
+Use this file for deploying senlin-api under Apache2(mode-wsgi).
+"""
+
+
+from oslo_config import cfg
+import oslo_i18n as i18n
+from oslo_log import log as logging
+
+from senlin.api.common import wsgi
+from senlin.common import messaging
+from senlin.common import profiler
+from senlin import version
+
+
+def init_app():
+    i18n.enable_lazy()
+
+    logging.register_options(cfg.CONF)
+    cfg.CONF(project='senlin', prog='senlin-api',
+             version=version.version_info.version_string())
+    logging.setup(cfg.CONF, 'senlin-api')
+    messaging.setup()
+
+    profiler.setup('senlin-api', cfg.CONF.host)
+    return wsgi.load_paste_app()

setup.cfg

@@ -29,6 +29,9 @@ console_scripts =
     senlin-engine = senlin.cmd.engine:main
     senlin-manage = senlin.cmd.manage:main
 
+wsgi_scripts =
+    senlin-wsgi-api = senlin.cmd.api_wsgi:init_app
+
 oslo.config.opts =
     senlin.config = senlin.common.config:list_opts