<html><body style="word-wrap: break-word; -webkit-nbsp-mode: space; -webkit-line-break: after-white-space;" class="">Hi Doug. <br class=""><br class="">The old and new MROs are both pretty complicated, and it’s not entirely clear to me yet why the original one worked. (The MROs are included below for reading pleasure; they're embellished to show the incoming args to self’s init and outgoing args to super’s init in each case.)<br class=""><br class="">I’m fairly sure the APIs for the mixins can be made the same, and I’ll try that. But I still wonder if in fact the problem is a base class ordering issue. <br class=""><br class="">The error that 223343 produced occurs in method call #6 in the "AFTER" MRO, where we get the following trace:<div class=""><br class=""><blockquote style="margin: 0 0 0 40px; border: none; padding: 0px;" class=""><font face="Courier" class=""><span class="Apple-tab-span" style="white-space:pre"> </span>super(PeriodicTasks, self).__init__()<br class="">TypeError: __init__() takes exactly 2 arguments (1 given)</font></blockquote><blockquote style="margin: 0 0 0 40px; border: none; padding: 0px;" class=""><br class=""></blockquote><br class="">For grins, we changed PeriodicTasks’s call to super init as suggested by the trace:</div><div class=""><br class=""><blockquote style="margin: 0 0 0 40px; border: none; padding: 0px;" class=""><div class=""><font face="Courier" class=""><span class="Apple-tab-span" style="white-space:pre"> </span>super(PeriodicTasks, self).__init__(conf)</font></div></blockquote><div class=""><br class=""><br class=""></div><div class="">At this point FWaaSAgentRpcCallbackMixin (AFTER, #8) complained:</div><div class=""><br class=""><blockquote style="margin: 0 0 0 40px; border: none; padding: 0px;" class=""><font face="Courier" class=""><span class="Apple-tab-span" style="white-space: pre;"> </span>super(FWaaSAgentRpcCallbackMixin, self).__init__(host)</font></blockquote><blockquote style="margin: 0 0 0 40px; border: none; padding: 0px;" class=""><font face="Courier" class="">TypeError: object.__init__() takes no parameters</font></blockquote><br class=""><br class=""></div><div class="">Changing *that* class as suggested elicited the following (to me baffling) result:</div><div class=""><div class=""><br class=""><blockquote style="margin: 0 0 0 40px; border: none; padding: 0px;" class=""><font face="Courier" class=""><span class="Apple-tab-span" style="white-space:pre"> </span>super(FWaaSAgentRpcCallbackMixin, self).__init__()</font></blockquote><blockquote style="margin: 0 0 0 40px; border: none; padding: 0px;" class=""><font face="Courier" class="">TypeError: __init__() takes exactly 2 arguments (1 given)</font></blockquote><br class=""><br class=""></div><div class="">I find it baffling because FWaaSAgentRpcCallbackMixin is the end of the line, it’s a subclass of object, and object doesn’t allow arguments to init (so whose init is that? that’s the next thing I’m going to look at). (It’s for these same reasons that I don’t understand why things worked before the 223343 change.)<br class=""><br class="">I’m still looking at things. (And learning about MRO, which I’ve never really dealt with before.) Will run pdb and see what surfaces. <br class=""><br class="">Thanks for your help. Thoughts, comments, suggestions all welcome.<br class="">Margaret<br class=""><br class=""><br class=""><font face="Courier" class="">BEFORE 223343<br class=""> 1. varmour_router_vArmourL3NATAgent <span class="Apple-tab-span" style="white-space:pre"> </span>(host, conf)-->(host, conf)<br class=""> 2. agent_L3NATAgent <span class="Apple-tab-span" style="white-space:pre"> </span>(host, conf)-->(conf)<br class=""> 3. firewall_l3_agent_FWaaSL3AgentRpcCallback <span class="Apple-tab-span" style="white-space:pre"> </span>(conf)-->(host)<br class=""> 4. api_FWaaSAgentRpcCallbackMixin <span class="Apple-tab-span" style="white-space:pre"> </span>(host)-->(host)<br class=""> 5. ha_AgentMixin<span class="Apple-tab-span" style="white-space:pre"> </span>(host)-->(host)<br class=""> 6. dvr_AgentMixin<span class="Apple-tab-span" style="white-space:pre"> </span>(host)-->(host)<br class=""> 7. manager_Manager<span class="Apple-tab-span" style="white-space:pre"> </span>(host)-->(conf)<br class=""> 8. periodic_task_PeriodicTasks<span class="Apple-tab-span" style="white-space:pre"> </span>(conf)-->()<br class=""> 9. firewall_l3_agent_FWaaSL3AgentRpcCallback<span class="Apple-tab-span" style="white-space:pre"> </span>(conf)-->(host)<br class="">10. api_FWaaSAgentRpcCallbackMixin<span class="Apple-tab-span" style="white-space:pre"> </span>(host)-->(host)<br class="">11. object<br class=""><br class="">AFTER 223343<br class=""> 1. varmour_router_vArmourL3NATAgent <span class="Apple-tab-span" style="white-space:pre"> </span>(host, conf)-->(host, conf)<br class=""> 2. agent_L3NATAgent <span class="Apple-tab-span" style="white-space:pre"> </span>(host, conf)-->(host)<br class=""> 3. ha_AgentMixin<span class="Apple-tab-span" style="white-space:pre"> </span>(host)-->(host)<br class=""> 4. dvr_AgentMixin<span class="Apple-tab-span" style="white-space:pre"> </span>(host)-->(host)<br class=""> 5. manager_Manager<span class="Apple-tab-span" style="white-space:pre"> </span>(host)-->(conf)<br class=""> 6. periodic_task_PeriodicTasks<span class="Apple-tab-span" style="white-space:pre"> </span>(conf)-->()<br class=""> 7. firewall_l3_agent_FWaaSL3AgentRpcCallback <span class="Apple-tab-span" style="white-space:pre"> </span>(conf)-->(host)<br class=""> 8. api_FWaaSAgentRpcCallbackMixin<span class="Apple-tab-span" style="white-space:pre"> </span>(host)-->(host)<br class=""> 9. object</font><br class=""><br class=""><div class="">--<br class="">Margaret Frances<br class="">Eng 4, Prodt Dev Engineering<br class=""><br class=""><br class=""></div><br class=""><blockquote type="cite" class="">On May 5, 2016, at 7:06 PM, Doug Hellmann <<a href="mailto:doug@doughellmann.com" class="">doug@doughellmann.com</a>> wrote:<br class=""><br class="">Excerpts from Nate Johnston's message of 2016-05-05 17:40:13 -0400:<br class=""><blockquote type="cite" class="">FWaaS team,<br class=""><br class="">After a day of looking at the tests currently failing in the FWaaS repo, I<br class="">believe I have the issue narrowed down considerably. First, to restate what<br class="">is going on. If you check out the neutron-fwaas repository and run `tox -e<br class="">py27` in it, you will get six errors all in the<br class="">neutron_fwaas.tests.unit.services.firewall.agents.varmour.test_varmour_router.TestVarmourRouter<br class="">section.<br class="">Running the py34 tests results in similar problems. The failures follow<br class="">the following form:<br class=""><br class="">Captured traceback:<br class=""><br class="">~~~~~~~~~~~~~~~~~~~<br class=""><br class=""> Traceback (most recent call last):<br class=""><br class=""> File<br class="">"neutron_fwaas/tests/unit/services/firewall/agents/varmour/test_varmour_router.py",<br class="">line 190, in test_agent_external_gateway<br class=""><br class=""> router = self._create_router()<br class=""><br class=""> File<br class="">"neutron_fwaas/tests/unit/services/firewall/agents/varmour/test_varmour_router.py",<br class="">line 87, in _create_router<br class=""><br class=""> router = varmour_router.vArmourL3NATAgent(HOSTNAME, self.conf)<br class=""><br class=""> File<br class="">"neutron_fwaas/services/firewall/agents/varmour/varmour_router.py", line<br class="">54, in __init__<br class=""><br class=""> super(vArmourL3NATAgent, self).__init__(host, conf)<br class=""><br class=""> File "/home/njohns002/<br class=""><a href="http://github.com/openstack/neutron-fwaas-311159/.tox/py27/src/neutron/neutron/agent/l3/agent.py" class="">github.com/openstack/neutron-fwaas-311159/.tox/py27/src/neutron/neutron/agent/l3/agent.py</a>",<br class="">line 244, in __init__<br class=""><br class=""> super(L3NATAgent, self).__init__(host=self.conf.host)<br class=""><br class=""> File "/home/njohns002/<br class=""><a href="http://github.com/openstack/neutron-fwaas-311159/.tox/py27/src/neutron/neutron/agent/l3/ha.py" class="">github.com/openstack/neutron-fwaas-311159/.tox/py27/src/neutron/neutron/agent/l3/ha.py</a>",<br class="">line 93, in __init__<br class=""><br class=""> super(AgentMixin, self).__init__(host)<br class=""><br class=""> File "/home/njohns002/<br class=""><a href="http://github.com/openstack/neutron-fwaas-311159/.tox/py27/src/neutron/neutron/agent/l3/dvr.py" class="">github.com/openstack/neutron-fwaas-311159/.tox/py27/src/neutron/neutron/agent/l3/dvr.py</a>",<br class="">line 30, in __init__<br class=""><br class=""> super(AgentMixin, self).__init__(host)<br class=""><br class=""> File "/home/njohns002/<br class=""><a href="http://github.com/openstack/neutron-fwaas-311159/.tox/py27/src/neutron/neutron/agent/l3/agent.py" class="">github.com/openstack/neutron-fwaas-311159/.tox/py27/src/neutron/neutron/agent/l3/agent.py</a>",<br class="">line 70, in __init__<br class=""><br class=""> super(FWaaSAgentRpcCallbackMixin, self).__init__(host)<br class=""><br class=""> File "/home/njohns002/<br class=""><a href="http://github.com/openstack/neutron-fwaas-311159/.tox/py27/src/neutron/neutron/manager.py" class="">github.com/openstack/neutron-fwaas-311159/.tox/py27/src/neutron/neutron/manager.py</a>",<br class="">line 44, in __init__<br class=""><br class=""> super(Manager, self).__init__(conf)<br class=""><br class=""> File "/home/njohns002/<br class=""><a href="http://github.com/openstack/neutron-fwaas-311159/.tox/py27/lib/python2.7/site-packages/oslo_service/periodic_task.py" class="">github.com/openstack/neutron-fwaas-311159/.tox/py27/lib/python2.7/site-packages/oslo_service/periodic_task.py</a>",<br class="">line 177, in __init__<br class=""><br class=""> super(PeriodicTasks, self).__init__()<br class=""><br class=""> TypeError: __init__() takes exactly 2 arguments (1 given)<br class=""><br class="">I pinged the Oslo folks, and they were able to help me look into the issue,<br class="">which cleared oslo.service of any role. The change that introduced this is<br class="">actually a neutron change - <a href="https://review.openstack.org/#/c/223343/" class="">https://review.openstack.org/#/c/223343/</a> - and<br class="">I could experimentally test for it by doing the following, which checks out<br class="">the change before the problem one, "Remove BGP code from neutron". At that<br class="">point `tox -e py27` could complete successfully.<br class=""><br class="">Everything works with the older commit: cd .tox/py27/src/neutron && git<br class="">checkout fe702f8f2af265554c7ff6f464b99562f8c54254 && cd - && tox -e py27<br class="">Things break with commit 223343: cd .tox/py27/src/neutron && git<br class="">checkout f31861843d90e013d31fb76fc576b49a35e218aa4 && cd - && tox -e py27<br class=""><br class="">My guess on this is that the reason for the breakage is due to multiple<br class="">inheritance and the changing of the ancestry for the L3NATAgent object. So<br class="">the focus of my effort (with Margaret Frances providing crucial insight) is<br class="">determining what precisely needs to be fixed or reverted to make this work,<br class="">while in keeping with the removal of FWaaS code from Neutron. I shall<br class="">continue to look at this tomorrow, but if anyone wishes to pick up the<br class="">torch and figure this out then you should feel free to do so. If not, I<br class="">shall resume tomorrow.<br class=""><br class="">Thanks,<br class=""><br class="">--N.<br class=""></blockquote><br class="">Based on looking at the class hierarchy for vArmourL3NATAgent, I think<br class="">the problem is that the mixin classes up and down that hierarchy don't<br class="">take the same arguments for __init__(). That's going to make using super()<br class="">difficult. Normally one would just need to switch the order of the base<br class="">classes so all of the mixins are initialized before the Manager and<br class="">PeriodicTask base classes, but doing that doesn't fix the problem in<br class="">this case.<br class=""><br class="">Is it possible to make all of the mixin APIs the same?<br class=""><br class="">Doug<br class=""><br class="">__________________________________________________________________________<br class="">OpenStack Development Mailing List (not for usage questions)<br class="">Unsubscribe: <a href="mailto:OpenStack-dev-request@lists.openstack.org" class="">OpenStack-dev-request@lists.openstack.org</a>?subject:unsubscribe<br class=""><a href="http://lists.openstack.org/cgi-bin/mailman/listinfo/openstack-dev" class="">http://lists.openstack.org/cgi-bin/mailman/listinfo/openstack-dev</a><br class=""><br class=""></blockquote><br class=""></div></div></div></body></html>