_get_filterid_for_ip can generate an UnboundLocalError

[Brian Haley]

After fixing a bug in the L3 extension API, https://review.openstack.org/#/c/626401/ - the l3-agent is getting a traceback in the QoS code running the dvr multinode scenario job.

neutron-l3-agent[14973]: ERROR neutron.agent.l3.agent [-] Failed to process compatible router: 7461a0e1-508c-4ff2-a559-6cc89a128ea5: UnboundLocalError: local variable 'filter_id' referenced before assignment
neutron-l3-agent[14973]: ERROR neutron.agent.l3.agent Traceback (most recent call last):
neutron-l3-agent[14973]: ERROR neutron.agent.l3.agent File "/opt/stack/neutron/neutron/agent/l3/agent.py", line 628, in _process_routers_if_compatible
neutron-l3-agent[14973]: ERROR neutron.agent.l3.agent self._process_router_if_compatible(router)
neutron-l3-agent[14973]: ERROR neutron.agent.l3.agent File "/opt/stack/neutron/neutron/agent/l3/agent.py", line 504, in _process_router_if_compatible
neutron-l3-agent[14973]: ERROR neutron.agent.l3.agent self._process_updated_router(router)
neutron-l3-agent[14973]: ERROR neutron.agent.l3.agent File "/opt/stack/neutron/neutron/agent/l3/agent.py", line 529, in _process_updated_router
neutron-l3-agent[14973]: ERROR neutron.agent.l3.agent self.l3_ext_manager.update_router(self.context, router)
neutron-l3-agent[14973]: ERROR neutron.agent.l3.agent File "/opt/stack/neutron/neutron/agent/l3/l3_agent_extensions_manager.py", line 54, in update_router
neutron-l3-agent[14973]: ERROR neutron.agent.l3.agent extension.obj.update_router(context, data)
neutron-l3-agent[14973]: ERROR neutron.agent.l3.agent File "/usr/local/lib/python3.6/dist-packages/oslo_concurrency/lockutils.py", line 328, in inner
neutron-l3-agent[14973]: ERROR neutron.agent.l3.agent return f(*args, **kwargs)
neutron-l3-agent[14973]: ERROR neutron.agent.l3.agent File "/opt/stack/neutron/neutron/agent/l3/extensions/qos/fip.py", line 292, in update_router
neutron-l3-agent[14973]: ERROR neutron.agent.l3.agent self.process_floating_ip_addresses(context, router_info)
neutron-l3-agent[14973]: ERROR neutron.agent.l3.agent File "/opt/stack/neutron/neutron/agent/l3/extensions/qos/fip.py", line 277, in process_floating_ip_addresses
neutron-l3-agent[14973]: ERROR neutron.agent.l3.agent self._remove_fip_rate_limit(device, fip)
neutron-l3-agent[14973]: ERROR neutron.agent.l3.agent File "/opt/stack/neutron/neutron/agent/l3/extensions/qos/fip.py", line 164, in _remove_fip_rate_limit
neutron-l3-agent[14973]: ERROR neutron.agent.l3.agent tc_wrapper.clear_ip_rate_limit(direction, fip_ip)
neutron-l3-agent[14973]: ERROR neutron.agent.l3.agent File "/opt/stack/neutron/neutron/agent/linux/l3_tc_lib.py", line 188, in clear_ip_rate_limit
neutron-l3-agent[14973]: ERROR neutron.agent.l3.agent filter_id = self._get_filterid_for_ip(qdisc_id, ip)
neutron-l3-agent[14973]: ERROR neutron.agent.l3.agent File "/opt/stack/neutron/neutron/agent/linux/l3_tc_lib.py", line 82, in _get_filterid_for_ip
neutron-l3-agent[14973]: ERROR neutron.agent.l3.agent filterids_for_ip.append(filter_id)
neutron-l3-agent[14973]: ERROR neutron.agent.l3.agent UnboundLocalError: local variable 'filter_id' referenced before assignment
neutron-l3-agent[14973]: ERROR neutron.agent.l3.agent

From this log file:

http://logs.openstack.org/01/626401/1/check/neutron-tempest-plugin-dvr-multinode-scenario/a7bcbe2/controller/logs/screen-q-l3.txt.gz?level=WARNING#_Dec_19_23_26_00_169583

The loop in _get_filterid_for_ip() doesn't look to protect against this case, we'd need to capture the output to see why it's failing.

[Slawek Kaplonski (slaweq)]

Patch is proposed for this one: https://review.openstack.org/#/c/630773/

[OpenStack Infra (hudson-openstack)]

Reviewed: https://review.openstack.org/630773
Committed: https://git.openstack.org/cgit/openstack/neutron/commit/?id=e788d294584add2407f601a46f90b08082cccc5f
Submitter: Zuul
Branch: master

commit e788d294584add2407f601a46f90b08082cccc5f
Author: Slawek Kaplonski <email address hidden>
Date: Mon Jan 14 22:29:25 2019 +0100

    Support iproute2 4.15 in l3_tc_lib

    In version 4.15 of iproute2 there was added support
    for chain index in tc_filter [1].
    Such version is available e.g. in Ubuntu 18.04 and it
    has to be supported in l3_tc_lib regex to match
    properly output of "tc filter" command.

    [1] https://lwn.net/Articles/745643/

    Closes-bug: #1809497
    Change-Id: Id4066b5cff933ccd0dd3c751bf67b5d58af662d1

[OpenStack Infra (hudson-openstack)]

This issue was fixed in the openstack/neutron 14.0.0.0b2 development milestone.

[OpenStack Infra (hudson-openstack)]

Fix proposed to branch: stable/rocky
Review: https://review.opendev.org/719751

[OpenStack Infra (hudson-openstack)]

Fix proposed to branch: stable/queens
Review: https://review.opendev.org/719752

[OpenStack Infra (hudson-openstack)]

Reviewed: https://review.opendev.org/719752
Committed: https://git.openstack.org/cgit/openstack/neutron/commit/?id=371204bc0e614b1af07ce25696d90f817dd9f949
Submitter: Zuul
Branch: stable/queens

commit 371204bc0e614b1af07ce25696d90f817dd9f949
Author: Slawek Kaplonski <email address hidden>
Date: Mon Jan 14 22:29:25 2019 +0100

    Support iproute2 4.15 in l3_tc_lib

    In version 4.15 of iproute2 there was added support
    for chain index in tc_filter [1].
    Such version is available e.g. in Ubuntu 18.04 and it
    has to be supported in l3_tc_lib regex to match
    properly output of "tc filter" command.

    [1] https://lwn.net/Articles/745643/

    Closes-bug: #1809497
    Change-Id: Id4066b5cff933ccd0dd3c751bf67b5d58af662d1
    (cherry picked from commit e788d294584add2407f601a46f90b08082cccc5f)

[OpenStack Infra (hudson-openstack)]

Reviewed: https://review.opendev.org/719751
Committed: https://git.openstack.org/cgit/openstack/neutron/commit/?id=e04ed368ad975b7a39262945b8900c13b7e13807
Submitter: Zuul
Branch: stable/rocky

commit e04ed368ad975b7a39262945b8900c13b7e13807
Author: Slawek Kaplonski <email address hidden>
Date: Mon Jan 14 22:29:25 2019 +0100

    Support iproute2 4.15 in l3_tc_lib

    In version 4.15 of iproute2 there was added support
    for chain index in tc_filter [1].
    Such version is available e.g. in Ubuntu 18.04 and it
    has to be supported in l3_tc_lib regex to match
    properly output of "tc filter" command.

    [1] https://lwn.net/Articles/745643/

    Closes-bug: #1809497
    Change-Id: Id4066b5cff933ccd0dd3c751bf67b5d58af662d1
    (cherry picked from commit e788d294584add2407f601a46f90b08082cccc5f)

[OpenStack Infra (hudson-openstack)]

This issue was fixed in the openstack/neutron queens-eol release.

[OpenStack Infra (hudson-openstack)]

This issue was fixed in the openstack/neutron rocky-eol release.