When create keypair with the same name at the same time, create two keypair

To fix this issue, I have added uniqueness constraint on name and user_id columns of key_pairs table (and removed the extra DB look-up prior to the creation of key pair). However, I am facing a strange issue in SQLAlchemy, due to which, I get a TypeError instead of IntegrityError (sample stack trace http://paste.openstack.org/show/28497/ ) on creating a same named keypair for a user.

This can be overcome by replacing the 'raise' statement by 'raise exc' in _flush( ) method of /usr/local/lib/python2.7/dist-packages/sqlalchemy/orm/session.py.

IMO, this requires a fix in SQLAlchemy session. Can someone please confirm this.

NOTE: Code branch 'master', SQLAlchemy version 0.7.9

I agree that concurrent usage of "_capture_exception=True" and "raise" is suspicious at best, so it looks like it would be worth reporting to SQLAlchemy folks.

Can someone please point out how to report this problem to the SQLAlchemy team?

I managed to fix the issue without modifying SQLAlchemy code. Calling session.begin( ) before calling the method save( ) and passing it the corresponding session instance fixes the issue. After the fix is in place, the expected exception 'DBDuplicateEntry' is getting raised on adding a duplicate row.

Does this solution sound correct?

PS: The same solution can also be used for similar issues (such as security group creation LP #1093458).

Fix proposed to branch: master
Review: https://review.openstack.org/19376

Fix proposed to branch: master
Review: https://review.openstack.org/21415

Please review this patch https://review.openstack.org/#/c/21415/.

Reviewed: https://review.openstack.org/21415
Committed: http://github.com/openstack/nova/commit/0ae598b1a7a92755fd0fcc2685816414fb6f47b0
Submitter: Jenkins
Branch: master

commit 0ae598b1a7a92755fd0fcc2685816414fb6f47b0
Author: Rohan Rhishikesh Kanade <email address hidden>
Date: Wed Feb 27 11:19:21 2013 -0800

    Return 409 on creating/importing same name keypair

    * Removed the DB look up on creating and importing a keypair.
    * Added unique constraint on user_id and name columns of key_pairs
    table.

    Fixes LP: #1086333.

    Change-Id: I2fd4697f9269d2be13bd977e65ba4ca4a27b9ac6