net polster vnic parsing causes can cause Attribute errors

[Dan Prince]

Using the latest version of Havana Ceilometer (git a9f147c) on Centos I'm seeing the following exceptions in the compute agent log file:

2013-09-05 01:57:45.422 8590 WARNING ceilometer.publisher.rpc [-] Publishing policy is unknown (wait) force to default
2013-09-05 01:57:45.423 8590 WARNING ceilometer.publisher.rpc [-] Publishing policy is unknown (wait) force to default
2013-09-05 11:07:46.777 8590 WARNING ceilometer.transformer.conversions [-] dropping sample with no predecessor: <ceilometer.sample.Sample object at 0x23a30d0>
2013-09-05 11:07:47.868 8590 WARNING ceilometer.compute.pollsters.net [-] Ignoring instance instance-00000001: 'NoneType' object has no attribute 'get'
2013-09-05 11:07:47.868 8590 ERROR ceilometer.compute.pollsters.net [-] 'NoneType' object has no attribute 'get'
2013-09-05 11:07:47.868 8590 TRACE ceilometer.compute.pollsters.net Traceback (most recent call last):
2013-09-05 11:07:47.868 8590 TRACE ceilometer.compute.pollsters.net File "/usr/lib/python2.6/site-packages/ceilometer/compute/pollsters/net.py", line 80, in get_samples
2013-09-05 11:07:47.868 8590 TRACE ceilometer.compute.pollsters.net instance_name,
2013-09-05 11:07:47.868 8590 TRACE ceilometer.compute.pollsters.net File "/usr/lib/python2.6/site-packages/ceilometer/compute/pollsters/net.py", line 69, in _get_vnics_for_instance
2013-09-05 11:07:47.868 8590 TRACE ceilometer.compute.pollsters.net inspector.inspect_vnics(instance_name)
2013-09-05 11:07:47.868 8590 TRACE ceilometer.compute.pollsters.net File "/usr/lib/python2.6/site-packages/ceilometer/compute/virt/libvirt/inspector.py", line 114, in inspect_vnics
2013-09-05 11:07:47.868 8590 TRACE ceilometer.compute.pollsters.net name = iface.find('target').get('dev')
2013-09-05 11:07:47.868 8590 TRACE ceilometer.compute.pollsters.net AttributeError: 'NoneType' object has no attribute 'get'
2013-09-05 11:07:47.868 8590 TRACE ceilometer.compute.pollsters.net
2013-09-05 11:07:47.881 8590 WARNING ceilometer.compute.pollsters.net [-] Ignoring instance instance-00000001: 'NoneType' object has no attribute 'get'
2013-09-05 11:07:47.881 8590 ERROR ceilometer.compute.pollsters.net [-] 'NoneType' object has no attribute 'get'

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The issue seems to be due to the fact that the libvirt domain doesn't always have a devices/interface/target element.

[OpenStack Infra (hudson-openstack)]

Fix proposed to branch: master
Review: https://review.openstack.org/45444

[OpenStack Infra (hudson-openstack)]

Reviewed: https://review.openstack.org/45444
Committed: http://github.com/openstack/ceilometer/commit/d6ab6d10a8e8abbb1114baf2d95d311eb8e23c4d
Submitter: Jenkins
Branch: master

commit d6ab6d10a8e8abbb1114baf2d95d311eb8e23c4d
Author: Dan Prince <email address hidden>
Date: Fri Sep 6 11:15:30 2013 -0400

    Handle missing libvirt vnic targets!

    Updates the libvirt inspector so that our vnic inspection
    can handle cases where the interface/target is missing.
    This can occur in some (usually transient) cases where
    Nova is pausing/migrating/etc an instance.

    Previously Ceilometer would functionally work fine but
    a rather long stack trace would get logged to the log file.

    Fixes LP Bug #1221784

    Change-Id: I7113c6e4bb4af622d517915d13147f5912bad126