Incorrect version header return incorrect error response

[Jamie Hannaford]

When the OpenStack-API-Version header is sent and:

- the version is outside the range of versions supported
- and is not the string "latest"

a `406 Not Acceptable` response should be returned, like so:

HTTP/1.1 406 Not Acceptable
Openstack-API-Version: magnum 5.3
Vary: OpenStack-API-Version

 {
    "errors": [
        {
            "request_id": "2ee92f06-8ede-4fb4-8921-b507601fb59d",
            "code": "magnum.microverion-unsupported",
            "status": 406,
            "title": "Requested microversion is unsupported",
            "detail": "Version 5.3 is not supported by the API. Minimum is 1.0 and maximum is 1.2.",
            "max_version": "1.2",
            "min_version": "1.0",
            "links": [
                {
                    "rel": "help",
                    "href": "http://developer.openstack.org/api-guide/compute/microversions.html"
                }
             ]
         }
     ]
}

This is in accordance with the new API-WG guideline [1].

However, Magnum currently returns a 500 Internal Server error. To test, execute the following:

$ curl -g -i -X GET http://127.0.0.1:9511/v1/baymodels -H "X-OpenStack-Magnum-API-Version: 1.0" -H "X-Auth-Token: $TOKEN"
HTTP/1.0 500 Internal Server Error
Date: Wed, 13 Apr 2016 08:53:23 GMT
Server: WSGIServer/0.1 Python/2.7.6
Content-Type: text/plain
Content-Length: 59

A server error occurred. Please contact the administrator.

[1] https://specs.openstack.org/openstack/api-wg/guidelines/microversion_specification.html

[Eli Qiao (taget-9)]

@Jamie, I can not reproduce this issue:

$ curl -g -i -X GET http://10.238.157.49:9511/v1/baymodels -H "X-OpenStack-Magnum-API-Version: 1.0" -H "X-Auth-Token: $auth_token"
HTTP/1.0 406 Not Acceptable
Date: Thu, 14 Apr 2016 01:17:51 GMT
Server: WSGIServer/0.1 Python/2.7.6
X-OpenStack-Magnum-API-Minimum-Version: 1.1
X-OpenStack-Magnum-API-Maximum-Version: 1.1
Content-Type: application/json
Content-Length: 99
x-openstack-request-id: req-2ef79e0e-05d5-4cad-98ff-10b1cd122bce

{"errors": [{"status": 406, "code": "", "links": [], "title": "", "detail": "", "request_id": ""}]}

[Jamie Hannaford (jamie-hannaford)]

I'm using devstack, do you know whether it could be wrapping errors with a generic 500 or something? This is the output from magnum-api:

Traceback (most recent call last):
  File "/usr/lib/python2.7/wsgiref/handlers.py", line 85, in run
    self.result = application(self.environ, self.start_response)
  File "/usr/local/lib/python2.7/dist-packages/webob/dec.py", line 130, in __call__
    resp = self.call_func(req, *args, **self.kwargs)
  File "/usr/local/lib/python2.7/dist-packages/webob/dec.py", line 195, in call_func
    return self.func(req, *args, **kwargs)
  File "/usr/local/lib/python2.7/dist-packages/oslo_middleware/base.py", line 114, in __call__
    response = req.get_response(self.application)
  File "/usr/local/lib/python2.7/dist-packages/webob/request.py", line 1317, in send
    application, catch_exc_info=False)
  File "/usr/local/lib/python2.7/dist-packages/webob/request.py", line 1281, in call_application
    app_iter = application(self.environ, start_response)
  File "/opt/stack/magnum/magnum/api/middleware/auth_token.py", line 60, in __call__
    return super(AuthTokenMiddleware, self).__call__(env, start_response)
  File "/usr/local/lib/python2.7/dist-packages/webob/dec.py", line 130, in __call__
    resp = self.call_func(req, *args, **self.kwargs)
  File "/usr/local/lib/python2.7/dist-packages/webob/dec.py", line 195, in call_func
    return self.func(req, *args, **kwargs)
  File "/usr/local/lib/python2.7/dist-packages/keystonemiddleware/auth_token/__init__.py", line 467, in __call__
    response = req.get_response(self._app)
  File "/usr/local/lib/python2.7/dist-packages/webob/request.py", line 1317, in send
    application, catch_exc_info=False)
  File "/usr/local/lib/python2.7/dist-packages/webob/request.py", line 1281, in call_application
    app_iter = application(self.environ, start_response)
  File "/usr/local/lib/python2.7/dist-packages/pecan/middleware/recursive.py", line 56, in __call__
    return self.application(environ, start_response)
  File "/opt/stack/magnum/magnum/api/middleware/parsable_error.py", line 64, in __call__
    err = json.loads(err_str)
  File "/usr/lib/python2.7/json/__init__.py", line 338, in loads
    return _default_decoder.decode(s)
  File "/usr/lib/python2.7/json/decoder.py", line 366, in decode
    obj, end = self.raw_decode(s, idx=_w(s, 0).end())
  File "/usr/lib/python2.7/json/decoder.py", line 384, in raw_decode
    raise ValueError("No JSON object could be decoded")
ValueError: No JSON object could be decoded
127.0.0.1 - - [14/Apr/2016 09:53:13] "GET /v1/baymodels HTTP/1.1" 500 59

[Jaycen Grant (jaycen-v-grant)]

I tested this and I don't see the 500 issues even on devstack. I do notice that the error response could be updated to add the details that are in the suggested response https://specs.openstack.org/openstack/api-wg/guidelines/microversion_specification.html. Would it be better to fix those as part of this bug or close this bug and fix separately?

I am working on making sure all of the microversioning is complete for magnum and this is one of the bugs that was filed around that implementation.

[OpenStack Infra (hudson-openstack)]

Fix proposed to branch: master
Review: https://review.openstack.org/339262

[OpenStack Infra (hudson-openstack)]

Reviewed: https://review.openstack.org/339262
Committed: https://git.openstack.org/cgit/openstack/magnum/commit/?id=deb10d32a9d57f4b8b2aa370a4ddfc349b41060c
Submitter: Jenkins
Branch: master

commit deb10d32a9d57f4b8b2aa370a4ddfc349b41060c
Author: Jaycen Grant <email address hidden>
Date: Thu Jul 7 07:21:10 2016 -0700

    Updates microversion root and error messages

    This change updates the microversion http errors, headers,
    and root response messages to match microversion specs
    that can be found here:
    https://specs.openstack.org/opnstack/api-wg/guidelines/
    microversion_specifications.html

    Closes-Bug: #1569777

    Change-Id: I18f52e569aeafaa98c56136d33d152fa420d9e1c

[OpenStack Infra (hudson-openstack)]

This issue was fixed in the openstack/magnum 3.0.0 release.