Neutron driver handles incorrectly 404 errors

[Cedric Brandily]

Neutronclient transforms errors using exception_handler_v20[1].
In particular, it transforms 404 responses into:
 1) [2] neutronclient.common.exceptions.<type>Client if response body contains a type attribute (with value <type>, type examples: NetworkNotFound, PortNotFound) and <type>Client exists
 2) [3] neutronclient.common.NotFound otherwise

Nova neutron driver[4] supports mostly 1) but not 2).
But Neutron in case of 404 returns the following body:

  {"message": "The resource could not be found.<br /><br />\n\n\n", "code": "404 Not Found", "title": "Not Found"}

and we end in 2) and Nova Neutron driver doesn't catch the error correctly and raises a 500

You can reproduce it indirectly using:
 openstack server add fixed ip <vm> <network-name>

which queries:
 nova-base-url/os-networks/<network-name>

assuming it would return the network or a 404 but it returns 500.

This trouble can be solved by catching NotFound instead of NetworkNotFoundClient/PortNotFoundClient as there are subclasses of NotFound.

[1] https://github.com/openstack/python-neutronclient/blob/6a2112e1824980af1bc9216441fa58a7dfd00988/neutronclient/v2_0/client.py#L47-L93
[2] https://github.com/openstack/python-neutronclient/blob/6a2112e1824980af1bc9216441fa58a7dfd00988/neutronclient/v2_0/client.py#L71
[3] https://github.com/openstack/python-neutronclient/blob/6a2112e1824980af1bc9216441fa58a7dfd00988/neutronclient/v2_0/client.py#L85
[4] nova.network.neutronv2.api

[Stepan G. Fedorov (stfedorov)]

Also got this issue in production.

openstack server add fixed ip <vm> <network-name> always results in 500.

We use Newton release, and need a bugfix ASAP.

[Alexey Stupnikov (astupnikov)]

This problem is not reproducible in stable/train:

$ openstack server add fixed ip 4a313732-138d-44aa-ba16-eac3d5ecf678 0b9d07e9-524d-4ab1-8206-5446af2d7746
none found (HTTP 404)

and in stable/queens:
$ openstack server add fixed ip d4d217ee-f1e3-497d-9835-8ae0e917c6a0 e2bc07ef-c7ba-4ca7-9c32-4803f852e21b
keys: ['label']
Not found (HTTP none found)

This bug seem to be a duplicate of bug #1649852

[Alexey Stupnikov (astupnikov)]

OK, maybe not a duplicate, but changed workflow for recent releases:

2020-05-23 17:18:34.101 17 DEBUG nova.api.openstack.wsgi [req-ea0481e8-4135-40fa-ba7d-008d95a205e4 e06bc0993eff4364a78724b2b121b58e 78e4238746cc4006b8288fdfca08725a - default default] Calli
ng method '<function version_select at 0x7f2253d9e050>' _process_stack /usr/lib/python2.7/site-packages/nova/api/openstack/wsgi.py:607
2020-05-23 17:18:34.136 17 DEBUG neutronclient.v2_0.client [req-ea0481e8-4135-40fa-ba7d-008d95a205e4 e06bc0993eff4364a78724b2b121b58e 78e4238746cc4006b8288fdfca08725a - default default] Err
or message: {"NeutronError": {"message": "Network e2bc07ef-c7ba-4ca7-9c32-4803f852e21b could not be found.", "type": "NetworkNotFound", "detail": ""}} _handle_fault_response /usr/lib/python
2.7/site-packages/neutronclient/v2_0/client.py:259
2020-05-23 17:18:34.137 17 INFO nova.api.openstack.wsgi [req-ea0481e8-4135-40fa-ba7d-008d95a205e4 e06bc0993eff4364a78724b2b121b58e 78e4238746cc4006b8288fdfca08725a - default default] HTTP e
xception thrown: Network not found
2020-05-23 17:18:34.138 17 DEBUG nova.api.openstack.wsgi [req-ea0481e8-4135-40fa-ba7d-008d95a205e4 e06bc0993eff4364a78724b2b121b58e 78e4238746cc4006b8288fdfca08725a - default default] Retur
ning 404 to user: Network not found __call__ /usr/lib/python2.7/site-packages/nova/api/openstack/wsgi.py:1064
2020-05-23 17:18:34.139 17 INFO nova.api.openstack.requestlog [req-ea0481e8-4135-40fa-ba7d-008d95a205e4 e06bc0993eff4364a78724b2b121b58e 78e4238746cc4006b8288fdfca08725a - default default] 172.17.1.15 "GET /v2.1/os-networks/e2bc07ef-c7ba-4ca7-9c32-4803f852e21b" status: 404 len: 63 microversion: 2.1 time: 0.041985

[Alexey Stupnikov (astupnikov)]

Changing bug's status to fix released as recent releases are no longer affected