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On Tue, Oct 28, 2014 at 07:34:11AM -0400, Sean Dague wrote:
> We're dealing with some issues on devstack pass through with really
> complicated config option types, the fixes are breaking other things.
> 
> The issue at hand is the fact that the pci pass through device listing
> is an olso MultiStrOpt in which each option value is fully valid json
> document, which must parse as such. That leads to things like:
> 
> pci_passthrough_whitelist = {"address":"*:0a:00.*",
> "physical_network":"physnet1"}
> pci_passthrough_whitelist = {"vendor_id":"1137","product_id":"0071"}
> 
> Which, honestly, seems a little weird for configs.
> 
> We're talking about a small number of fixed fields here, so the use of a
> full json doc seems weird. I'd like to reopen why this was the value
> format, and if we could have a more simple one.

Do you have ant suggestion for an alternative config syntax for specifying
a list of dicts which would be suitable ?

One option would be a more  CSV like syntax eg

   pci_passthrough_whitelist = address=*0a:00.*,physical_network=physnet1
   pci_passthrough_whitelist = vendor_id=1137,product_id=0071

But this gets confusing if we want to specifying multiple sets of data
so might need to use semi-colons as first separator, and comma for list
element separators

   pci_passthrough_whitelist = vendor_id=8085;product_id=4fc2, vendor_id=1137;product_id=0071

Overall it isn't clear that inventing a special case language for this PCI
config value is a good idea.

I think it illustrates a gap in oslo.config, which ought to be able to
support a config option type which was a "list of dicts of strings"
so anywhere which needs such a beast will use the same syntax.

Regards,
Daniel
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