Middlelware to ensure request ID

The feature of the proposed middleware is simple:
* Generate request-id for each REST request
* Set the generated request-id to request environment
* Add X-OpenStack-Request-Id header to API response to return request-id

blueprint middleware-request-id

Note that to use this middleware with Context, we need to change
auth middlware so that request-id will be retreived from request env.

Change-Id: Ic7967cd62e7b743343d70f751b9238339171e013

2 files changed, 75 insertions, 0 deletions

diff --git a/openstack/common/middleware/request_id.py b/openstack/common/middleware/request_id.py
new file mode 100644
index 0000000..d71eb6e
--- /dev/null
+++ b/openstack/common/middleware/request_id.py
@@ -0,0 +1,38 @@
+# Copyright (c) 2013 NEC Corporation
+# All Rights Reserved.
+#
+#    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.
+
+"""Middleware that ensures request ID.
+
+It ensures to assign request ID for each API request and set it to
+request environment. The request ID is also added to API response.
+"""
+
+from openstack.common import context
+from openstack.common.middleware import base
+
+
+ENV_REQUEST_ID = 'openstack.request_id'
+HTTP_RESP_HEADER_REQUEST_ID = 'x-openstack-request-id'
+
+
+class RequestIdMiddleware(base.Middleware):
+
+    def process_request(self, req):
+        self.req_id = context.generate_request_id()
+        req.environ[ENV_REQUEST_ID] = self.req_id
+
+    def process_response(self, response):
+        response.headers.add(HTTP_RESP_HEADER_REQUEST_ID, self.req_id)
+        return response
diff --git a/tests/unit/middleware/test_request_id.py b/tests/unit/middleware/test_request_id.py
new file mode 100644
index 0000000..bdd903d
--- /dev/null
+++ b/tests/unit/middleware/test_request_id.py
@@ -0,0 +1,37 @@
+# Copyright (c) 2013 NEC Corporation
+# All Rights Reserved.
+#
+#    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.
+
+
+from testtools import matchers
+import webob
+import webob.dec
+
+from openstack.common.middleware import request_id
+from openstack.common import test
+
+
+class RequestIdTest(test.BaseTestCase):
+    def test_generate_request_id(self):
+        @webob.dec.wsgify
+        def application(req):
+            return req.environ[request_id.ENV_REQUEST_ID]
+
+        app = request_id.RequestIdMiddleware(application)
+        req = webob.Request.blank('/test')
+        res = req.get_response(app)
+        res_req_id = res.headers.get(request_id.HTTP_RESP_HEADER_REQUEST_ID)
+        self.assertThat(res_req_id, matchers.StartsWith('req-'))
+        # request-id in request environ is returned as response body
+        self.assertEqual(res_req_id, res.body)