showing nonexistent NetworkGateway throws 500 instead of 404

[Mitsuru Kanabuchi]

I'm implementing nvp network gateway to heat.

  https://blueprints.launchpad.net/heat/+spec/resource-type-nvp-network-gateway

Heat would check resource existence by resource-show after resource deleted.
However, show_network_gateway returns 500 instead of 404 when nvp network gateway isn't exist.
The result of this situation is that Heat is unable to delete nvp network gateway.

I think, neutron should return 404 when resource isn't exist.

Curl:

$ curl -i http://172.23.56.142:9696/v2.0/network-gateways/b5afd4a9-eb71-4af7-a082-8fc625a35b61 -X GET -H "X-Auth-Token: 56c136ee847f476f9f0ba4c2ca78ae4b" -H "Content-Type: application/json" -H "Accept: application/json" -H "User-Agent: python-neutronclient"
HTTP/1.1 500 Internal Server Error
Content-Type: application/json; charset=UTF-8
Content-Length: 88
Date: Mon, 18 Nov 2013 10:30:44 GMT

{"NeutronError": "Request Failed: internal server error while processing your request."}

Log:

2013-11-18 18:18:03.315 25570 DEBUG keystoneclient.middleware.auth_token [-] Received request from user: 54012987ac014457b9a0a8bcc10928ae with project_id : ed684e101d3243a69db07e744acad6f2 and roles: admin _build_user_headers /opt/stack/python-keystoneclient/keystoneclient/middleware/auth_token.py:922
2013-11-18 18:18:03.316 25570 DEBUG routes.middleware [-] Matched GET /network-gateways/3fe90063-9e96-45be-8989-335f582962be.json __call__ /usr/lib/python2.7/dist-packages/routes/middleware.py:100
2013-11-18 18:18:03.317 25570 DEBUG routes.middleware [-] Route path: '/network-gateways/:(id).:(format)', defaults: {'action': u'show', 'controller': <wsgify at 65809104 wrapping <function resource at 0x3ebbf50>>} __call__ /usr/lib/python2.7/dist-packages/routes/middleware.py:102
2013-11-18 18:18:03.317 25570 DEBUG routes.middleware [-] Match dict: {'action': u'show', 'controller': <wsgify at 65809104 wrapping <function resource at 0x3ebbf50>>, 'id': u'3fe90063-9e96-45be-8989-335f582962be', 'format': u'json'} __call__ /usr/lib/python2.7/dist-packages/routes/middleware.py:103
2013-11-18 18:18:03.324 25570 ERROR neutron.api.v2.resource [-] show failed
2013-11-18 18:18:03.324 25570 TRACE neutron.api.v2.resource Traceback (most recent call last):
2013-11-18 18:18:03.324 25570 TRACE neutron.api.v2.resource File "/opt/stack/neutron/neutron/api/v2/resource.py", line 84, in resource
2013-11-18 18:18:03.324 25570 TRACE neutron.api.v2.resource result = method(request=request, **args)
2013-11-18 18:18:03.324 25570 TRACE neutron.api.v2.resource File "/opt/stack/neutron/neutron/api/v2/base.py", line 290, in show
2013-11-18 18:18:03.324 25570 TRACE neutron.api.v2.resource parent_id=parent_id),
2013-11-18 18:18:03.324 25570 TRACE neutron.api.v2.resource File "/opt/stack/neutron/neutron/api/v2/base.py", line 258, in _item
2013-11-18 18:18:03.324 25570 TRACE neutron.api.v2.resource obj = obj_getter(request.context, id, **kwargs)
2013-11-18 18:18:03.324 25570 TRACE neutron.api.v2.resource File "/opt/stack/neutron/neutron/plugins/nicira/NeutronPlugin.py", line 1951, in get_network_gateway
2013-11-18 18:18:03.324 25570 TRACE neutron.api.v2.resource id, fields)
2013-11-18 18:18:03.324 25570 TRACE neutron.api.v2.resource File "/opt/stack/neutron/neutron/plugins/nicira/dbexts/nicira_networkgw_db.py", line 248, in get_network_gateway
2013-11-18 18:18:03.324 25570 TRACE neutron.api.v2.resource gw_db = self._get_network_gateway(context, id)
2013-11-18 18:18:03.324 25570 TRACE neutron.api.v2.resource File "/opt/stack/neutron/neutron/plugins/nicira/dbexts/nicira_networkgw_db.py", line 133, in _get_network_gateway
2013-11-18 18:18:03.324 25570 TRACE neutron.api.v2.resource return self._get_by_id(context, NetworkGateway, gw_id)
2013-11-18 18:18:03.324 25570 TRACE neutron.api.v2.resource File "/opt/stack/neutron/neutron/db/db_base_plugin_v2.py", line 145, in _get_by_id
2013-11-18 18:18:03.324 25570 TRACE neutron.api.v2.resource return query.filter(model.id == id).one()
2013-11-18 18:18:03.324 25570 TRACE neutron.api.v2.resource File "/usr/local/lib/python2.7/dist-packages/sqlalchemy/orm/query.py", line 2190, in one
2013-11-18 18:18:03.324 25570 TRACE neutron.api.v2.resource raise orm_exc.NoResultFound("No row was found for one()")
2013-11-18 18:18:03.324 25570 TRACE neutron.api.v2.resource NoResultFound: No row was found for one()
2013-11-18 18:18:03.324 25570 TRACE neutron.api.v2.resource
2013-11-18 18:18:05.061 25570 DEBUG neutron.openstack.common.rpc.amqp [-] received {u'_context_roles': [u'admin'], u'_msg_id': u'3ce98f89ac844d2a8d38e0ae231ff447', u'_context_read_deleted': u'no', u'_reply_q': u'reply_70a7a3f33d8f4417b5225404d435d264', u'_context_tenant_id': None, u'args': {u'devices': [u'tap3fc478a3-07', u'tapfa59a846-8b', u'tapba4de5a8-85']}, u'namespace': None, u'_unique_id': u'44f59887e1084f9898cdcc57d3bcff78', u'_context_is_admin': True, u'version': u'1.1', u'_context_project_id': None, u'_context_timestamp': u'2013-11-14 10:51:59.225787', u'_context_user_id': None, u'method': u'security_group_rules_for_devices'} _safe_log /opt/stack/neutron/neutron/openstack/common/rpc/common.py:276
2013-11-18 18:18:05.061 25570 DEBUG neutron.openstack.common.rpc.amqp [-] unpacked context: {'user_id': None, 'roles': [u'admin'], 'tenant_id': None, 'is_admin': True, 'timestamp': u'2013-11-14 10:51:59.225787', 'project_id': None, 'read_deleted': u'no'} _safe_log /opt/stack/neutron/neutron/openstack/common/rpc/common.py:276

[OpenStack Infra (hudson-openstack)]

Fix proposed to branch: master
Review: https://review.openstack.org/58423

[OpenStack Infra (hudson-openstack)]

Reviewed: https://review.openstack.org/58423
Committed: http://github.com/openstack/neutron/commit/68369fe6789d4ab053eb382458562394ce632de8
Submitter: Jenkins
Branch: master

commit 68369fe6789d4ab053eb382458562394ce632de8
Author: berlin <email address hidden>
Date: Tue Nov 26 09:02:27 2013 +0800

    Fix showing nonexistent NetworkGateway throws 500 instead of 404

    Change-Id: I5304bd52f7a5ae22fbc0d48206d7c1d282b34a91
    Closes-Bug: #1252921