Fix missing X-OpenStack-Request-ID header

Request ID is essential in operating OpenStack services, especially
when troubleshooting some API problems. It allows us to find out
the log lines actually related to a specific request.

However watcher api hasn't returned it properly, so operators had no
way to determine the exact ID they should search.

Add RequestID middleware to return the id in X-OpenStack-Request-Id
header, which is globally used.

Closes-Bug: #2122350
Change-Id: Ie4a8307e8e7e981cedbeaf5fe731dbd47a50bade
Signed-off-by: Takashi Kajinami <kajinamit@oss.nttdata.com>

releasenotes/notes/request-id-fdfe63effd88be78.yaml

@@ -0,0 +1,5 @@
+---
+fixes:
+  - |
+    Now request id is returned by Watcher API in the `X-OpenStack-Request-ID`
+    response header.

requirements.txt

@@ -19,6 +19,7 @@ oslo.db>=4.44.0 # Apache-2.0
 oslo.i18n>=3.20.0 # Apache-2.0
 oslo.log>=3.37.0 # Apache-2.0
 oslo.messaging>=14.1.0 # Apache-2.0
+oslo.middleware>=3.31.0 # Apache-2.0
 oslo.policy>=4.5.0 # Apache-2.0
 oslo.reports>=1.27.0 # Apache-2.0
 oslo.serialization>=2.25.0 # Apache-2.0

watcher/api/app.py

@@ -17,6 +17,7 @@
 #    under the License.
 
 
+from oslo_middleware import request_id
 import pecan
 
 from watcher.api import acl
@@ -42,13 +43,22 @@ def setup_app(config=None):
         app_conf.pop('root'),
         logging=getattr(config, 'logging', {}),
         debug=CONF.debug,
-        wrap_app=parsable_error.ParsableErrorMiddleware,
+        wrap_app=_wrap_app,
         **app_conf
     )
 
     return acl.install(app, CONF, config.app.acl_public_routes)
 
 
+def _wrap_app(app):
+    """Wraps wsgi app with additional middlewares."""
+    app = parsable_error.ParsableErrorMiddleware(app)
+
+    app = request_id.RequestId(app)
+
+    return app
+
+
 class VersionSelectorApplication(object):
     def __init__(self):
         pc = get_pecan_config()

watcher/tests/api/test_root.py

@@ -24,6 +24,12 @@ class TestRoot(base.FunctionalTest):
         # Check fields are not empty
         [self.assertNotIn(f, ['', []]) for f in data.keys()]
 
+    # NOTE(tkajinam): Request ID should be present in any request so we verify
+    # it only at the root path.
+    def test_request_id(self):
+        resp = self.get_json('/', path_prefix='', return_json=False)
+        self.assertIn('X-OpenStack-Request-Id', resp.headers)
+
 
 class TestV1Root(base.FunctionalTest):