Open Stack

On 10/28/2014 07:44 AM, Daniel P. Berrange wrote:
> 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.

Mostly, why do we need name= at all. This seems like it would be fine as
an fstab like format (with 'x' as an ignore value).

# vendor_id product_id address
pci_passthrough_whitelist = 8085
pci_passthrough_whitelist = 1137 4fc2
pci_passthrough_whitelist = x 0071
pci_passthrough_whitelist = x x *0a:00.*

Basically going to a full name = value seems incredibly overkill for
something with < 6 fields.

	-Sean

-- 
Sean Dague
http://dague.net