Add X-OpenStack-Request-Id header

Make sure request id is returned in the X-OpenStack-Request-Id response
header so that clients/users can determine the id used to look up
corresponding logs.

Change-Id: Ied7b98629423545c23ce664b22525f3d8fb9d253
Signed-off-by: Takashi Kajinami <kajinamit@oss.nttdata.com>

releasenotes/notes/request-id-cbc8150626c0ccc3.yaml

@@ -0,0 +1,5 @@
+---
+features:
+  - |
+    Now API returnes unique request identifier string in
+    the ``X-OpenStack-Request-Id`` header.

zaqar/transport/wsgi/driver.py

@@ -18,6 +18,7 @@ import socket
 from wsgiref import simple_server
 
 from oslo_log import log as logging
+from oslo_middleware import request_id
 from oslo_utils import netutils
 
 from zaqar.common import decorators
@@ -148,6 +149,8 @@ class Driver(transport.DriverBase):
 
         self.app = auth.SignedAndExtraSpecHeadersAuth(self.app, auth_app)
 
+        self.app = request_id.RequestId(self.app)
+
         # NOTE(wangxiyuan): Install CORS, this middleware should be called
         # before Keystone auth.
         self.app = cors.install_cors(self.app, auth_app, self._conf)