Re: [netmod] XPath questions about revised datastores

[Phil Shafer <[e-mail]>]

Andy Bierman writes:
>It has always been OK for a config=false data node's XPath expression to
>point at a config=true data node.
>But this has always meant the configured value. RD changes this behavior
>because the new opstate datastore
>contains only the operational values of config=true nodes. Now there is no
>way for such an XPath expression
>to test the configured value.

The XPath will refer to the current operational value, which is
better defined and more consistent behavior.  During the lack when
data is flowing between <intended> and <operational> as system
components read and follow new incoming configuration data, the
operational value should be guiding the constraints, not the
unrealized incoming value.

The XPath continues to work in a backwards compatible manner, but
the outcome is more crisply defined and the <operational> datastore
will have better odds of being self-consistent.

Thanks,
 Phil