policy engine swallows exception on critical code execution

[Armando Migliaccio]

I have noticed that if the following code (where F is a plugin method):

            data = f(context.get_admin_context(),
                     target[parent_foreign_key],
                     fields=[parent_field])
            target[self.target_field] = data[parent_field]

raises an exception this is not logged making very hard to understand why the policy check has failed.

[OpenStack Infra (hudson-openstack)]

Fix proposed to branch: master
Review: https://review.openstack.org/33339

[OpenStack Infra (hudson-openstack)]

Reviewed: https://review.openstack.org/33339
Committed: http://github.com/openstack/quantum/commit/8eea1ae574671a157ae2d215f18635a3c8985a06
Submitter: Jenkins
Branch: master

commit 8eea1ae574671a157ae2d215f18635a3c8985a06
Author: armando-migliaccio <email address hidden>
Date: Mon Jun 17 13:33:46 2013 -0700

    Make sure exceptions during policy checks are logged.

    If the invocation of f bombs out, the policy check fails (i.e. returns
    False), however it does not log the root cause, which makes very
    difficult to understand why this is happening.

    Fixes bug #1191948

    Change-Id: Ic40053f3965b71199baf9fe3902e8ffc9745076f