[openstack-dev] [Heat] Dealing with nonexistent resources during resource-list / stack-delete
sbaker at redhat.com
Tue Mar 8 22:50:06 UTC 2016
On 09/03/16 05:41, Johannes Grassler wrote:
> On 03/08/2016 04:57 PM, Zane Bitter wrote:
>> On 08/03/16 10:40, Johannes Grassler wrote:
>>> On 03/07/2016 04:48 PM, Zane Bitter wrote:
>>>> On 04/03/16 04:35, Johannes Grassler wrote:
>>> [Uncaught client exceptions in resource plugins' add_dependencies()
>>>> In the meantime, we need to find and squash every instance of this
>>>> wherever we can like you said.
>>> It might also be a good idea to caution against unchecked API client
>>> invocations in
>> It's best if they *do* omit it entirely. The only reason we override
>> it in
>> the Neutron resources is that the Neutron API is terrible for
>> purposes. It adds a bunch of invisible, fragile magic that breaks in
>> subtle ways when e.g. resources are moved into nested stacks.
> I never saw the Neutron API that way before (I guess I just got used
> to the
> unintuitive bits), but seeing it spelled out in your rant makes it very
> obvious, yes. I didn't know that was the root cause for overriding
> add_dependencies() and that very ignorance of mine...
>> The default implementation provides everything that we *ought* to
>> need, so if
>> we document anything I think it should be that plugin developers
>> should not
>> touch add_dependencies() at all.
> ...suggests mentioning that much is probably a good idea (lest
> somebody pick
> one of the Neutron plugins as a template to base their own resource
>> Definitely not big enough to require a spec IMO.
> Yes, I can see that, given how it's not something plugin writers
> should do
> anyway. Then I'll just write a little paragraph cautioning against
> add_dependcies() and add a Related-Bug: line.
Thanks for that. The paragraph could say that it is preferable to not
override add_dependencies, but if they do then they should *never* make
REST API calls inside it. This is for the reason you've discovered, and
also because it will kill the performance of some stack operations.
From what I can see you've discovered the only 2 places where REST API
calls are made from add_dependencies, I've added comments to the
review to suggest how they can be removed.
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