Ladislav Lhotka je 30.7.2015 ob 13:35 napisal:
On 30 Jul 2015, at 13:31, Jernej Tuljak <jern...@mg-soft.si> wrote:
Ladislav Lhotka je 30.7.2015 ob 11:30 napisal:
On 30 Jul 2015, at 01:12, Andy Bierman <a...@yumaworks.com> wrote:
On Wed, Jul 29, 2015 at 10:51 AM, Martin Bjorklund <m...@tail-f.com> wrote:
Andy Bierman <a...@yumaworks.com> wrote:
Hi,
I understand the intent is that an implementation of NACM
has to understand these NACM extensions. I agree with Lada
that the YANG text about MAY ignore extensions casts doubt whether
this sort of NACM rule is enforceable or specified correctly.
So do you agree that it would be a good idea to clarify this
according to Juergen's suggestion?
Not really.
Pretending the extension is just another description-stmt
does not really fix anything.
In fact, generic tools like pyang ignore what’s written in descriptions.
Where does RFC6020 say that description-stmt may be used for defining
additional semantics? The only instance where I can find
Nowhere. That’s why I also proposed to add the following sentence to the
section about “description” statement:
Constraints and rules stated in the text of a “description” statement are an
integral and binding part of the data model.
Wait, what? This would make a client broken if it chokes after receiving
a message, where a container data node instance has a text value set and
the container's description in the module claims: "This container MUST
be treated as a leaf under X Y conditions".
It is in this WG interest for YANG modules to be interpreted without
human presence, right? Automation? If it isn't, it would be best to drop
YANG and write human readable specifications instead. Models that cannot
be consumed by machines are pointless, IMHO.
Jernej
Lada
"description" and "semantics" or "meaning" in the same sentence, is in the
section that describes module updates. This is what a YANG description is:
The "description" statement takes as an argument a string that
contains a human-readable textual description of this definition.
The text is provided in a language (or languages) chosen by the
module developer; for the sake of interoperability, it is RECOMMENDED
to choose a language that is widely understood among the community of
network administrators who will use the module.
A textual description for humans. A docstring. I don't see semantics being
mentioned anywhere, so where is all this coming from?
Jernej
Lada
A real YANG statement like config-stmt or a new statement
called ephemeral-stmt can be modified with refine-stmt
or deviate-stmt. This can never happen for
an external statement.
IMO ephemeral data support needs to be a real statement
that can be used with refine-stmt and deviate-stmt.
It is a real property of a data node.
/martin
Andy
Andy
On Wed, Jul 29, 2015 at 10:44 AM, Martin Bjorklund <m...@tail-f.com> wrote:
Andy Bierman <a...@yumaworks.com> wrote:
The real difference is that extensions can be ignored by all
YANG tools and real statements cannot be ignored.
Are you saying that a server that advertises both ietf-system and nacm
is free to ignore the nacm statements in ietf-system, and for example
by default provide read-access to
/system/radius/server/udp/shared-secret?
/martin
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Ladislav Lhotka, CZ.NIC Labs
PGP Key ID: E74E8C0C
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Ladislav Lhotka, CZ.NIC Labs
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