Re: [netmod] attributes in draft-lhotka-netmod-yang-json
Martin Bjorklund <mbj@tail-f.com> Wed, 26 March 2014 15:51 UTC
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Date: Wed, 26 Mar 2014 16:51:13 +0100
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From: Martin Bjorklund <mbj@tail-f.com>
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Archived-At: http://mailarchive.ietf.org/arch/msg/netmod/XOZTIzONUlq2nnLGFYP1y0sQ2d0
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Subject: Re: [netmod] attributes in draft-lhotka-netmod-yang-json
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Andy Bierman <andy@yumaworks.com> wrote: > On Wed, Mar 26, 2014 at 8:12 AM, Martin Bjorklund <mbj@tail-f.com> wrote: > > > Ladislav Lhotka <lhotka@nic.cz> wrote: > > > > > > On 26 Mar 2014, at 15:43, Andy Bierman <andy@yumaworks.com> wrote: > > > > > > > > > > > > > > > > > > > On Wed, Mar 26, 2014 at 7:27 AM, Martin Bjorklund <mbj@tail-f.com> > > > > wrote: > > > > Andy Bierman <andy@yumaworks.com> wrote: > > > > > On Wed, Mar 26, 2014 at 7:10 AM, Ladislav Lhotka <lhotka@nic.cz> > > > > > wrote: > > > > > > > > > > > > > > > > > On 26 Mar 2014, at 14:57, Martin Bjorklund <mbj@tail-f.com> wrote: > > > > > > > > > > > > > Ladislav Lhotka <lhotka@nic.cz> wrote: > > > > > > >> Martin Bjorklund <mbj@tail-f.com> writes: > > > > > > >> > > > > > > >>> Hi, > > > > > > >>> > > > > > > >>> Here's yet another attempt to handle attributes in JSON, > > without > > > > > > >>> changing the encoding for the case that there are no attributes > > > > > > >>> present. > > > > > > >>> > > > > > > >>> In all examples, the attributes "inactive" and "etag" are > > present. > > > > > > >>> > > > > > > >>> Attributes are encoded differently depending on the type of > > object: > > > > > > >>> > > > > > > >>> > > > > > > >>> leaf > > > > > > >>> ---- > > > > > > >>> > > > > > > >>> Encode the attributes as a sibling to the leaf. > > > > > > >>> > > > > > > >>> > > > > > > >>> leaf foo { > > > > > > >>> type string; > > > > > > >>> } > > > > > > >>> > > > > > > >>> "foo": "some value"; > > > > > > >>> "@foo": { > > > > > > >>> "inactive": true, > > > > > > >>> "etag": "..."; > > > > > > >>> } > > > > > > >>> > > > > > > >>> > > > > > > >>> list instance > > > > > > >>> ------------- > > > > > > >>> > > > > > > >>> Encode the attributes within the list instance. > > > > > > >>> > > > > > > >>> > > > > > > >>> list bar { > > > > > > >>> key name; > > > > > > >>> leaf name { > > > > > > >>> type string; > > > > > > >>> } > > > > > > >>> ... > > > > > > >>> } > > > > > > >>> > > > > > > >>> "bar": [ > > > > > > >>> { > > > > > > >>> "@bar": { > > > > > > >>> "inactive": true, > > > > > > >>> "etag": "..." > > > > > > >>> } > > > > > > >>> "name": "instance name"; > > > > > > >>> }] > > > > > > >>> > > > > > > >> > > > > > > >> This could be ambiguous: > > > > > > >> > > > > > > >> list bar { > > > > > > >> key name; > > > > > > >> leaf name { ... } > > > > > > >> leaf bar { ... } > > > > > > >> } > > > > > > >> > > > > > > >> Then you don't know whether the attributes belong to the list > > entry > > > > > > >> or to the contained leaf. > > > > > > > > > > > > > > Right. Then we use "@@bar" for the list / container attributes. > > > > > > > > > > > > OK, then this scheme is fine with me. > > > > > > > > > > > > > > > > > Looks more complicated than other solution proposals. > > > > > > > > Do we agree that we don't want different encodings for values if there > > > > are attributes or not? I.e., if my code works when no attributes are > > > > present, it should also work if there are attributes? > > > > > > I am not sure even your encoding satisfies this requirement. At least > > > your code has to be instructed to ignore the attribute stuff. > > > > In general, I think robust code would ignore unknown fields. > > > > > > Not if the normal encoding is painful to use. > > > > The use attributes is going to be rare. > > > > I want the expected "plain" encoding when there are no attributes. > > > > Code that generates JSON and does not care about attributes > > > > must not be rendered useless because the JSON is specially encoded > > > > in RESTCONF. We want to leverage wide knowledge of JSON, > > > > not invent our own incompatible version of it. > > > > > > This is my preference, too. > > > > > This is not a preference. It is critical that plain JSON code > that knows how to deal with plain data structures does not break. > > Well, of course. But I don't think anyone has proposed something that > > is not valid json. > > > > > > That is not the point. A normal JSON tool is going to generate or expect > "foo":"bar" for a simple leaf, or "foo":[1, 2, 3] for a simple array, for > example. > > The encoding for the data nodes MUST be exactly > the same as the YANG-to-JSON draft now, if no attributes are used. This is exactly my point! > Only a client that knows about attributes will need to associate an > attribute > with its parent data node. Yes! > This must be easy to do. As easy as possible. IMO this falls into the category of "possible to do". The normal case must be easy to do. > Other clients should be able to ignore attributes. Yes! > A server must reject messages with unknown attributes. > > I agree that no proposal is satisfactory for leaf or leaf-list nodes. My proposal satifies all these properties, except "easy to do attributes". /martin
- [netmod] attributes in draft-lhotka-netmod-yang-j… Dean Bogdanovic
- Re: [netmod] attributes in draft-lhotka-netmod-ya… Martin Bjorklund
- Re: [netmod] attributes in draft-lhotka-netmod-ya… Andy Bierman
- Re: [netmod] attributes in draft-lhotka-netmod-ya… Martin Bjorklund
- Re: [netmod] attributes in draft-lhotka-netmod-ya… Ladislav Lhotka
- Re: [netmod] attributes in draft-lhotka-netmod-ya… Andy Bierman
- Re: [netmod] attributes in draft-lhotka-netmod-ya… Andy Bierman
- Re: [netmod] attributes in draft-lhotka-netmod-ya… Ladislav Lhotka
- Re: [netmod] attributes in draft-lhotka-netmod-ya… Andy Bierman
- Re: [netmod] attributes in draft-lhotka-netmod-ya… Andy Bierman
- Re: [netmod] attributes in draft-lhotka-netmod-ya… Ladislav Lhotka
- Re: [netmod] attributes in draft-lhotka-netmod-ya… Martin Bjorklund
- Re: [netmod] attributes in draft-lhotka-netmod-ya… Andy Bierman
- Re: [netmod] attributes in draft-lhotka-netmod-ya… Andy Bierman
- Re: [netmod] attributes in draft-lhotka-netmod-ya… Ladislav Lhotka
- Re: [netmod] attributes in draft-lhotka-netmod-ya… Andy Bierman
- Re: [netmod] attributes in draft-lhotka-netmod-ya… Ladislav Lhotka
- Re: [netmod] attributes in draft-lhotka-netmod-ya… Andy Bierman
- Re: [netmod] attributes in draft-lhotka-netmod-ya… Ladislav Lhotka
- Re: [netmod] attributes in draft-lhotka-netmod-ya… Andy Bierman
- Re: [netmod] attributes in draft-lhotka-netmod-ya… Martin Bjorklund
- Re: [netmod] attributes in draft-lhotka-netmod-ya… Ladislav Lhotka
- Re: [netmod] attributes in draft-lhotka-netmod-ya… Martin Bjorklund
- Re: [netmod] attributes in draft-lhotka-netmod-ya… Ladislav Lhotka
- Re: [netmod] attributes in draft-lhotka-netmod-ya… Andy Bierman
- Re: [netmod] attributes in draft-lhotka-netmod-ya… Martin Bjorklund
- Re: [netmod] attributes in draft-lhotka-netmod-ya… Andy Bierman
- Re: [netmod] attributes in draft-lhotka-netmod-ya… Ladislav Lhotka
- Re: [netmod] attributes in draft-lhotka-netmod-ya… Martin Bjorklund
- Re: [netmod] attributes in draft-lhotka-netmod-ya… Martin Bjorklund
- Re: [netmod] attributes in draft-lhotka-netmod-ya… Andy Bierman
- Re: [netmod] attributes in draft-lhotka-netmod-ya… Martin Bjorklund
- Re: [netmod] attributes in draft-lhotka-netmod-ya… Andy Bierman