Add http_proxy_to_wsgi middleware

It allows the application to detect the real endpoint used by clients,
when API is deployed behind forwarders such as load balancers.

Change-Id: I63d477e6bea2cf214ca050fedeec2240d864ab3b
Signed-off-by: Takashi Kajinami <kajinamit@oss.nttdata.com>

etc/cyborg/api-paste.ini

@@ -1,5 +1,5 @@
 [pipeline:main]
-pipeline = cors request_id authtoken api_v2
+pipeline = cors http_proxy_to_wsgi request_id authtoken api_v2
 
 [app:api_v2]
 paste.app_factory = cyborg.api.app:app_factory
@@ -17,3 +17,6 @@ paste.filter_factory = oslo_middleware:RequestId.factory
 [filter:cors]
 paste.filter_factory =  oslo_middleware.cors:filter_factory
 oslo_config_project = cyborg
+
+[filter:http_proxy_to_wsgi]
+paste.filter_factory = oslo_middleware.http_proxy_to_wsgi:HTTPProxyToWSGI.factory

tools/config/cyborg-config-generator.conf

@@ -5,6 +5,7 @@ namespace = cyborg
 namespace = oslo.db
 namespace = oslo.messaging
 namespace = oslo.middleware.cors
+namespace = oslo.middleware.http_proxy_to_wsgi
 namespace = oslo.policy
 namespace = oslo.log
 namespace = oslo.service.service