API Create - duplicate names returns a 500 Error

[Alun Champion]

When setting osapi_compute_unique_server_name_scope to project or global, duplicate names in the appropriate scope should return a BadRequest (400) but currently returns a ClientException (500), with an unhelpful message.

In nova.api.openstack.compute.Controller.create InstanceExists exception is not caught and mapped to BadRequest.

[Christopher Yeoh (cyeoh-0)]

I think 409 conflict is more appropriate that 400 bad request

[OpenStack Infra (hudson-openstack)]

Fix proposed to branch: master
Review: https://review.openstack.org/125863

[Alun Champion (prof-f)]

Does this constituent a change in the API spec, I don't believe 409 is listed as one of the error response codes?

[Christopher Yeoh (cyeoh-0)]

Its a change, but not a backwards incompatible change. Our API Change guidelines allow for the
changing error codes (not success ones) if the new one is more appropriate.

https://wiki.openstack.org/wiki/APIChangeGuidelines

[OpenStack Infra (hudson-openstack)]

Reviewed: https://review.openstack.org/125863
Committed: https://git.openstack.org/cgit/openstack/nova/commit/?id=8cedf63e5ccc9a023884b77fc460f8372300012d
Submitter: Jenkins
Branch: master

commit 8cedf63e5ccc9a023884b77fc460f8372300012d
Author: Chris Yeoh <email address hidden>
Date: Fri Oct 3 12:15:23 2014 +0930

    Correctly catch InstanceExists in servers create API

    When osapi_compute_unique_server_name_scope is set to project
    or global an attempt to create a server with a name which
    already exists results in an InstanceExists exception being raised.
    This was not being handled in the API layer causing a 500
    status error code. This patch fixes it so the exception is caught
    correctly and a 409 Conflict is returned instead

    Change-Id: Ifee3476622b227991a4c2a2780ae7ff23787ccb9
    Closes-Bug:1376936

[OpenStack Infra (hudson-openstack)]

Fix proposed to branch: stable/icehouse
Review: https://review.openstack.org/128583

[OpenStack Infra (hudson-openstack)]

Fix proposed to branch: stable/icehouse
Review: https://review.openstack.org/130189

[OpenStack Infra (hudson-openstack)]

Fix proposed to branch: stable/juno
Review: https://review.openstack.org/130456

[OpenStack Infra (hudson-openstack)]

Change abandoned by Artem Yasakov (<email address hidden>) on branch: stable/icehouse
Review: https://review.openstack.org/128583
Reason: repeated changes https://review.openstack.org/#/c/130189/

[OpenStack Infra (hudson-openstack)]

Change abandoned by Matt Riedemann (<email address hidden>) on branch: stable/icehouse
Review: https://review.openstack.org/130189
Reason: At this point we're looking to end of life stable/icehouse and given this isn't a critical bug fix I don't think it's worth backporting to icehouse.

[OpenStack Infra (hudson-openstack)]

Change abandoned by Matt Riedemann (<email address hidden>) on branch: stable/juno
Review: https://review.openstack.org/130456
Reason: stable/juno is in support phase 2 which is security/critical fixes only, so given this is a low severity fix and has some concern about API changes (although OK on master), we are going to abandon this.

https://wiki.openstack.org/wiki/StableBranch#Support_phases