Resource create/update/delete failures not always caught

[Steven Hardy]

We have a (broken IMO) pattern where resource.create(), resource.update() and resource.delete() are treated as having failed if they return a value, e.g:

result = res.create()
if result:
    stack_status = self.CREATE_FAILED

The problem is if any Exception gets raised without a string description we return an empty string, which is treated as if no error has occurred.

E.g try putting "raise Exception()" in any resource handle_create - result is an empty string so result is evaluated as False and the resource will not be set to CREATE_FAILED state.

The quick fix is to replace all the Exception-return-as-string bits in resource.py:

return str(ex)

with:

return str(ex) or "Error : %s" % type(ex)

Or something similar, but longer term, I think we need to look at this pattern and replace it with re-raising an Exception so it can be caught e.g in parser.py instead of relying on the non-standard error-if-it-returns-a-value behavior.

[OpenStack Infra (hudson-openstack)]

Fix proposed to branch: master
Review: https://review.openstack.org/22336

[OpenStack Infra (hudson-openstack)]

Reviewed: https://review.openstack.org/22336
Committed: http://github.com/openstack/heat/commit/2f4b981cd4a373cb66af935558e2ed3a779dd202
Submitter: Jenkins
Branch: master

commit 2f4b981cd4a373cb66af935558e2ed3a779dd202
Author: Steven Hardy <email address hidden>
Date: Tue Feb 19 18:17:02 2013 +0000

    heat engine : avoid returning empty resource error strings

    Avoid the possibility of returning an empty string (when Exceptions
    have not got a string message), or parser.py will treat the error
    as success and the resource operation failure will not be correctly
    reflected in the resource state.

    fixes bug 1130270

    Change-Id: I1c55dea1f9615cd4b037802ff8c1066694bffea6