Original exceptions and tracebacks are lost on error

[Alex Meade]

Many except blocks catch exceptions and only log partial information before raising a new exception. We should at least log the original exceptions information and traceback. Example below. In these cases, we should be logging the info with LOG.exception instead of LOG.error. Otherwise, it can be very difficult for an admin to determine the root issue.

https://github.com/openstack/cinder/blob/d943bafbb8908ba9f85be8e2a0e48a80d27ae48a/cinder/volume/flows/manager/create_volume.py#L465

464 except Exception as ex:
465 LOG.error(_("Failed to copy image %(image_id)s to " <--------------- If this were Log.exception, the exception details would be logged
466 "volume: %(volume_id)s, error: %(error)s") %
467 {'volume_id': volume_id, 'error': ex,
468 'image_id': image_id})
469 if not isinstance(ex, exception.ImageCopyFailure):
470 raise exception.ImageCopyFailure(reason=ex)
471 else:
472 raise

[OpenStack Infra (hudson-openstack)]

Fix proposed to branch: master
Review: https://review.openstack.org/165380

[OpenStack Infra (hudson-openstack)]

Reviewed: https://review.openstack.org/165380
Committed: https://git.openstack.org/cgit/openstack/cinder/commit/?id=3eadd939bb1ef1dcb27402672d06691958a585ca
Submitter: Jenkins
Branch: master

commit 3eadd939bb1ef1dcb27402672d06691958a585ca
Author: Yuriy Nesenenko <email address hidden>
Date: Wed Mar 18 13:45:48 2015 +0200

    Fix logging to catch original exceptions and tracebacks

    We should log the original exceptions information and tracebacks
    with LOG.exception instead of LOG.error. Otherwise, it can be
    difficult to determine the root issue. Also, the module
    cinder/volume/flows/manager/create_volume.py is fixed according to
    Logging guidelines http://docs.openstack.org/developer/oslo.i18n/guidelines.html

    Closes-Bug: #1309177

    Change-Id: I01d7667ddb9f7698efcf412a40f76809852cfaa1