internal NotFound error can lead to 500 error in modern devstack setup

[Chris Dent]

I'm using a recent devstack in late October 2018, no special keystone configuration, it is running under uwsgi and apache2.

If I make a request of the service to a bogus URL:

====
curl -v http://localhost/identity/v3/narf

> GET /identity/v3/narf HTTP/1.1
> Host: localhost
> User-Agent: curl/7.58.0
> Accept: */*
>
< HTTP/1.1 500 INTERNAL SERVER ERROR
< Date: Fri, 26 Oct 2018 10:08:34 GMT
< Server: Apache/2.4.29 (Ubuntu)
< Content-Type: application/json
< Content-Length: 138
< Vary: X-Auth-Token
< x-openstack-request-id: req-cfafa26b-75a9-4573-9076-61ff9290c6a7
< Connection: close
<
{"error":{"code":500,"message":"An unexpected error prevented the server from fulfilling your request.","title":"Internal Server Error"}}
====

I stumbled upon this because I was experimenting with pulling the catalog and requests /v3/catalog instead of /v3/services

Which doesn't seem ideal :)

[Colleen Murphy (krinkle)]

git bisect shows this is the commit that introduced it https://review.openstack.org/609796

[OpenStack Infra (hudson-openstack)]

Fix proposed to branch: master
Review: https://review.openstack.org/613961

[OpenStack Infra (hudson-openstack)]

Reviewed: https://review.openstack.org/613961
Committed: https://git.openstack.org/cgit/openstack/keystone/commit/?id=ee490d82262804ce1d6cee301594294733a71b79
Submitter: Zuul
Branch: master

commit ee490d82262804ce1d6cee301594294733a71b79
Author: Morgan Fainberg <email address hidden>
Date: Mon Oct 29 08:26:31 2018 -0700

    Unregister "Exception" from flask handler

    Unregister the default Exception from the flask error handler. This
    is to allow flask 404 to bubble up outside of test cases normally with
    out raising a 500 error.

    Change-Id: I2159952acae0234472ee3fea7f387278cbefa6c3
    Closes-Bug: #1800124

[OpenStack Infra (hudson-openstack)]

This issue was fixed in the openstack/keystone 15.0.0.0rc1 release candidate.