errors_out_migration decorator does not work with RPC calls

[John Warren]

The errors_out_migration decorator in nova/compute/manager.py is attempting to use positional arguments to get the migration parameter. However, at run time, the decorated methods are called via RPC calls which specify all of their arguments as keyword arguments. The decorator needs to be fixed so that it works with RPC calls.

[Matt Riedemann (mriedem)]

Patch is here: https://review.openstack.org/#/c/84215

This was a bug introduced late in Icehouse.

[Matt Riedemann (mriedem)]

(2:37:29 PM) mriedem: jswarren: so what do we lose when that fails?
(2:38:02 PM) mriedem: jswarren: it's a decorator on resize_instance and finish_resize that sets the migration.status to error right?
(2:38:16 PM) jswarren: It will continuously log that a migration is being skipped.
(2:38:23 PM) mriedem: jswarren: oh, so we're no worse off than the original bug
(2:38:29 PM) mriedem: that the decorator was added for
(2:38:39 PM) jswarren: correct.
(2:38:42 PM) mriedem: jswarren: i'd consider that less than high priority for icehouse, it could be a backport
(2:38:56 PM) jswarren: Yeah, that's what I thought. Just wanted to confirm.

[John Warren (jswarren)]

I got requests for a traceback or other log info when the failure occurs... The failure is actually silent. The code iterates through the args list, but it is empty, because the decorated methods were called with only kwargs, so there is no log or traceback to add to this bug.

[OpenStack Infra (hudson-openstack)]

Reviewed: https://review.openstack.org/84215
Committed: https://git.openstack.org/cgit/openstack/nova/commit/?id=72cd430e971589f7872a9d4e8f173c68b4955375
Submitter: Jenkins
Branch: master

commit 72cd430e971589f7872a9d4e8f173c68b4955375
Author: John Warren <email address hidden>
Date: Mon Mar 31 18:52:12 2014 +0000

    Change errors_out_migration decorator to work with RPC

    This decorator in nova/compute/manager.py was written to work with
    positional arguments, but at run time the decorated methods are
    called via RPC with keyword arguments. This change fixes the
    decorator and the associated test cases.

    Closes-Bug: #1300380

    Change-Id: I9f87151a71e5217e7eff97cdc5cad2c85b620fa5

[Openstack Gerrit (openstack-gerrit)]

Fix proposed to branch: stable/icehouse
Review: https://review.openstack.org/89655

[OpenStack Infra (hudson-openstack)]

Reviewed: https://review.openstack.org/89655
Committed: https://git.openstack.org/cgit/openstack/nova/commit/?id=66c7ca1ed63ac08afaa62728f7a165769bca5b56
Submitter: Jenkins
Branch: stable/icehouse

commit 66c7ca1ed63ac08afaa62728f7a165769bca5b56
Author: John Warren <email address hidden>
Date: Mon Mar 31 18:52:12 2014 +0000

    Change errors_out_migration decorator to work with RPC

    This decorator in nova/compute/manager.py was written to work with
    positional arguments, but at run time the decorated methods are
    called via RPC with keyword arguments. This change fixes the
    decorator and the associated test cases.

    Closes-Bug: #1300380

    Change-Id: I9f87151a71e5217e7eff97cdc5cad2c85b620fa5
    (cherry picked from commit 72cd430e971589f7872a9d4e8f173c68b4955375)