[openstack-dev] [oslo] Any reason why not have 'choices' parameter for ListOpt()?
doug at doughellmann.com
Mon Mar 26 20:26:21 UTC 2018
Excerpts from Matt Riedemann's message of 2018-03-26 14:12:52 -0500:
> On 3/26/2018 6:24 AM, ChangBo Guo wrote:
> > What's your use case for ListOpt, just make sure the value(a list) is
> > part of 'choices' ? Maybe we need another parameter to distinguish
> It came up because of this change in nova:
> We want to backport that as a bug fix which is a mitigation for
> performance degradation issues with QEMU patches for Spectre and Meltdown.
> However, in the backport we wanted to restrict the ListOpt to a single
> value, "pcid". The idea is to restrict the new option to a single value
> in stable branches.
> Then in master, we could remove the 'choices' kwarg so operators can
> define their list as they wish.
So we would have to backport a feature to oslo.config to allow a list to
> If we were do implement this generically in ListOpt, I suppose 'choices'
> would mean that the specified list must be a subset of the defined
> choices list. So in the backport patch, we'd just have choices=[None,
> 'pcid'] and you can either specify None or 'pcied' for that option
> (default to None).
What does it mean if they set the option to a list containing both
> Right now the code that's relying on this option just has a hard-coded
> check for the value which is OK.
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