Glance allows image location updates (removal, replacement) for images in non-active state

[Dharini Chandrasekar]

Currently image location updates (removing, replacing) are permitted for
images even if their state is not ``active``.
Glance must prevent removal and replacement of image
locations of images that are not ``active`` by returning a Conflict Error (409 response code).

WIP: https://review.openstack.org/#/c/366995/

TODO: Atomicity in glance such that, glance permits removal/replacement of
image locations on certain permissible image transition states.
For example, when the status of the image is ``deactivated`` and it
has just been moved to ``active``, removing/replacing the custom location
may be allowed.

[Nikhil Komawar (nikhil-komawar)]

https://review.openstack.org/#/c/366995/

[OpenStack Infra (hudson-openstack)]

Reviewed: https://review.openstack.org/366995
Committed: https://git.openstack.org/cgit/openstack/glance/commit/?id=4ac8adbccc2b7bbef3d53f9141079c48f9c768f4
Submitter: Jenkins
Branch: master

commit 4ac8adbccc2b7bbef3d53f9141079c48f9c768f4
Author: Nikhil Komawar <email address hidden>
Date: Wed Sep 7 17:29:41 2016 -0400

    Restrict location updates to active, queued images

    Currently image location updates (removing, replacing) are permitted for
    images even if their state is not ``active``.

    This need is to:
     * Prevent the replacement of image locations of images that are not
       ``active`` or ``queued`` by returning a Conflict Error
        (409 response code).
     * Prevent removal of image locations of images that are not ``active``
       by returning a Conflict Error (409 response code).

    Changing of image locations when the image state is not ``active`` can
    result in bad experiences for the users.
     * If one tries to change or remove the location for an image while it
        is in ``saving`` state, Glance would be trying to write data to a
        previously saved location while the user updates the custom
        location. This results in a race condition.
     * For images that are in ``queued`` state and no image data has been
        uploaded yet, there is no need for an image location to be
        removed and permitting users to remove the image
        location can result in a bad experience. However users can be
        allowed to replace the image location to maintain backward
        compatibility and also because replacing could mean replacing an
        empty location by a non-empty image location.
    * For images in ``deactivated`` state, it is essential that image
        locations are not updated as it does not abide with the purpose of
        the image state being set to ``deactivated`` and may cause security
        concerns.

    This commit introduces the following change in behavior:
      * If an image is in ``active`` state, removing/replacing the custom
        locations on that image will be allowed so there is no change in
        behavior for this case.
      * If an image is in ``saving`` or ``deactivated``, the status of
        that image will be checked while trying to replace/remove the custom
        location and a HTTP 409 Conflict status will be returned in response
        to the user.
      * If an image is in ``queued`` state, removing the custom
        image location will not be permitted as an image in queued status
        should not have any location associated with it. Replacing of location
        may be permitted here though.
      * If an image is in ``deleted`` or ``pending_delete`` state, a HTTP
        409 Conflict status will be returned, if that image is visible to
        the user (in case of admins). Otherwise, the location cannot be
        removed/replaced anyway. Please note ``pending_delete`` is another
        form of the ``deleted`` status and behavior in either case should be
        expected to be same.
      * If an image is in ``killed`` status, a HTTP 409 Conflict status will
        be returned.

    TODO:...

[OpenStack Infra (hudson-openstack)]

Fix proposed to branch: stable/newton
Review: https://review.openstack.org/408706

[OpenStack Infra (hudson-openstack)]

This issue was fixed in the openstack/glance 14.0.0.0b2 development milestone.

[OpenStack Infra (hudson-openstack)]

Change abandoned by Tony Breeds (<email address hidden>) on branch: stable/newton
Review: https://review.openstack.org/408706
Reason: This branch (stable/newton) is at End Of Life