[openstack-dev] [heat] Stack/Resource updated_at conventions

Angus Salkeld asalkeld at mirantis.com
Wed Apr 29 03:12:57 UTC 2015

On Tue, Apr 28, 2015 at 1:46 AM, Steven Hardy <shardy at redhat.com> wrote:

> Hi all,
> I've been looking into $subject recently, I raised this bug:
> https://bugs.launchpad.net/heat/+bug/1448155
> Basically we've got some historically weird and potentially inconsistent
> behavior around updated_at, and I'm trying to figure out the best way to
> proceed.
> Now, we selectively update updated_at only on the transition to
> UPDATE_COMPLETE, where we store the time that we moved into
> UPDATE_IN_PROGRESS.  During the update, there's no way to derive the
> time we started the update.
> Also, we inconsistently store the time associated with the transition into
> IN_PROGRESS for suspend, resume, snapshot, restore and check actions (even
> though many of these don't modify the stack definition).
> The reason I need this is the hook/breakpoint API - the only way to detect
> if you've hit a breakpoint is via events, and to detect you've hit a hook
> during multiple sequential updates (some of which may fail or time out with
> hooks pending), you need to filter the events to only consider those with a
> timestamp newer than the transition of the stack to the update IN_PROGRESS.
> AFAICT there's two options:
> 1. Update the stack.Stack so we store "now" at every transition (e.g in
> state_set)
> 2. Stop trying to explicitly control updated_at, and just allow the oslo
> TimestampMixin to do it's job and update updated_at every time the DB model
> is updated.
> What are peoples thoughts?  Either will solve my problem, but I'm leaning
> towards (2) as the cleanest and most technically correct solution.

Just beware:

This is our only current way for knowing if something has changed between 2


> Similar problems exist for resource.Resource AFAICT.
> Steve
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