glance metadef tables need unique constraints

Fix proposed to branch: master
Review: https://review.openstack.org/#/c/195820/

This bug actually describes the root cause of what I was running into using metadef import.

In my case, here is how to reproduce:
- run 'glance-manage db unload_metadefs'
- Log into Horizon
- import compute-libvirt.json
- then import compute-libvirt.json again
- Notice you get an error that it can't add the metadef
- Now click on Metadata Definitions again. Notice you get an error again. Metadata Definitions are no longer useable. In fact, the only way to recover is to run 'glance-manage db unload_metadefs'

Here's the traceback when this occurs: http://paste.openstack.org/show/412256/

The root cause is no unique constraint on table metadef_namespaces, column namespace

Note that this is a duplicate of bug 1479385 (or vice versa).

Jeremy,

I don't know how the duplication should be dealt with while the DOS condition was not called out here, the behavior was explained already month before logging of 1479385 and the attack surface cleared by Eric's comment #2 @ 08.08. So yes, Id's say the 1479385 is the duplicate.

I will look into this how we get the backporting moving forward for Kilo as soon as possible, specially now if the master fix merges.

Reviewed: https://review.openstack.org/195820
Committed: https://git.openstack.org/cgit/openstack/glance/commit/?id=5369e86e8d521115228573dd1878d764cd249e97
Submitter: Jenkins
Branch: master

commit 5369e86e8d521115228573dd1878d764cd249e97
Author: Wayne Okuma <email address hidden>
Date: Thu Jun 25 17:07:01 2015 -0700

    Glance metadef tables need unique constraints.

    Sometime during Kilo, the unique constraints on
    metadef_namespaces (namespace)
    metadef_objects(namespace_id, name)
    metadef_properties(namespace_id, name)
    metadef_tags(namespace_id, name)
    metadef_resource_types(name)
    were replaced with non-unique indices.

    I believe this was done erroneously to make the migrate_repo/versions/scripts
    match the db/sqlalchemy/models_metadef.py definitions. Unfortunately, the
    schema scripts were correct with the unique constraints and what should have
    changed was models_metadef.py.

    This bug, puts one more migrate script in place which will rename any
    duplicate records it finds to make them unique and then re-establishes
    the unique constraints while dropping the non-unique indices. It also,
    fixes models_metadef.py and adds in tests to attempt to create duplicates
    which should result in an HTTPConflict.

    Change-Id: Idf3569a27d64abea3ed6ec92fb77b36a4d6d5fd5
    Closes-Bug: 1468946

This was raised as a possible backport for Kilo and I see the nomination already. In response to the request made, I think making the DB migration doesn't really fit the rules of backports. The question remains is there a way to avoid the DOS? I currently can't think of one.