Pecan: policy evaluation error can trigger 500 response

[Salvatore Orlando]

in [1] if policy_method == enforce an PolicyNotAuthorizedException is triggered.
However, the exception translation hook is not called, most likely because the on_error hook is not installed on other policy hooks.
This might be logical and should therefore not be considered a pecan bug.

The policy hook should take this into account and handle the exception.

[1] http://git.openstack.org/cgit/openstack/neutron/tree/neutron/pecan_wsgi/hooks/policy_enforcement.py#n94

[OpenStack Infra (hudson-openstack)]

Fix proposed to branch: master
Review: https://review.openstack.org/234457

[OpenStack Infra (hudson-openstack)]

Reviewed: https://review.openstack.org/234457
Committed: https://git.openstack.org/cgit/openstack/neutron/commit/?id=293c3e01efce74d110ff34703a9e68ce2cd782e6
Submitter: Jenkins
Branch: master

commit 293c3e01efce74d110ff34703a9e68ce2cd782e6
Author: Salvatore Orlando <email address hidden>
Date: Tue Oct 13 15:08:47 2015 -0700

    Pecan: Fixes and tests for the policy enforcement hook

    As PolicyNotAuthorizedException is raised in a hook, the
    ExceptionTranslationHook is not invoked for it; therefore a 500
    response is returned whereas a 403 was expected. This patch
    explicitly handles the exception in the hook in order to ensure
    the appropriate response code is returned.

    Moreover, the structure of the 'before' hook prevented checks
    on DELETE requests from being performed. As a result the check
    was not performed at all (checks on the 'after' hook only pertain
    GET requests). This patch changes the logic of the 'before' hook
    by ensuring the item to authorize acces to is loaded both on PUT
    and DELETE requests.

    This patch also adds functional tests specific for the policy
    enforcement hook.

    Change-Id: I8c76cb05568df47648cff71a107cfe701b286bb7
    Closes-Bug: #1520180
    Closes-Bug: #1505831

[Thierry Carrez (ttx)]

This issue was fixed in the openstack/neutron 8.0.0.0b2 development milestone.