- From: Rudolf J Streif <rudolf.streif@ibeeto.com>
- Date: Tue, 11 Feb 2020 08:27:39 -0800
- To: Ulf Bjorkengren <ulfbjorkengren@geotab.com>, "Schildt Sebastian (CR/AEX1)" <Sebastian.Schildt@de.bosch.com>
- Cc: Magnus Feuer <mfeuer1@jaguarlandrover.com>, "public-automotive@w3.org" <public-automotive@w3.org>
- Message-ID: <1be376fc-9ec7-7210-270b-9079eab64e87@ibeeto.com>
I am top posting since I would like to take a step back (and then a leap
forward).
I think the discussion jumped too quickly from "what" to "how". The
"what" being an agreement on RPC and their purpose within VSS and the
"how" being the discussion about protocols etc.
What is the purpose of RPC within VSS? How is it intended to be used?
Magnus made the example of opening a window. If that is the only purpose
then what is the added value? The current VSS specification already
calls for read and write access to signals. In this case RPC would only
be a specific implementation mechanism to access a resource. The same
can be achieved with REST. And there is not much beyond what is already
in the specification.
I think RPC gets more interesting if there are more complex or compound
operations to be carried out. Or it could be an abstraction. For example
an RPC call could be secureVehicle(). It is a generic call and what the
vehicle actually does would depend on the vehicle's implementation. Some
vehicles might close all the windows, sun roofs, lock the doors, apply
the parking brake, arm the alarm, send current position information,
etc. Others might just do a subset.
Now RPC is so Nineties. Since vehicles are distributed compute
environments and everybody is talking about the next generation of
in-vehicle networking architecture shouldn't this effort be more forward
looking and think of this in terms of a mircoservices architecture?
:rjs
On 2/11/20 2:18 AM, Ulf Bjorkengren wrote:
> >> Or you introduce some “RPC” endpoints in the data model that
> expect some complex input data and specifying return values. My
> feeling is that the latter is too much.
> I fully agree.
>
> >> Maybe there is some middle ground, where one can define that there is
> an RPC mechanism (which means, transports need to have a support a
> generic query/response scheme that can do more than
> “writeInt()->Done()”), but not defining/modelling detailed RPC
> signaturess in VSS?
>
> I think it is necessary to put proposals of this on the table to be
> able to say yes or no to the question.
> The JLR proposal is one, which has the advantage that it does not
> require any modification of the standard (I believe?).
>
> BR
> Ulf
>
>
> On Tue, Feb 11, 2020 at 10:26 AM Schildt Sebastian (CR/AEX1)
> <Sebastian.Schildt@de.bosch.com
> <mailto:Sebastian.Schildt@de.bosch.com>> wrote:
>
> Hi,
>
>
>
> so I feel the main issue here is one of scope for VISS:
>
>
>
> We definitely can have HTTP, “Classic”-Websocket, WAMP, MQTT, etc.
> as “transports”, and the VISS specification might just reference
> them as optional parts such as “IF you want to do REST with VISS ;
> HERE is how we suggest you do it, in case of WAMP map it like
> this, for MQTT….” A little bit like convergence layers in Bundle
> Protocol.
>
>
>
> But the question really is should the underlying data model
> understand the notion of RPCs? If an actor is just a node in the
> tree you can write to, and what will really happen is sort of
> hidden. Or you introduce some “RPC” endpoints in the data model
> that expect some complex input data and specifying return values.
> My feeling is that the latter is too much. (It might make VISS a
> feature monster….). Maybe there is some middle ground, where one
> can define that there is an RPC mechanism (which means, transports
> need to have a support a generic query/response scheme that can
> do more than “writeInt()->Done()”), but not defining/modelling
> detailed RPC signaturess in VSS?
>
>
>
>
>
>
>
> Mit freundlichen Grüßen / Best regards
>
> *Sebastian Schildt
> CR/AEX1
> *
> Tel. +49 711 811-15765 | Mobil +49 173 7124227
> *
> ► Take a look at Bosch Research: www.bosch.com/research
> <http://www.bosch.com/research>
>
>
> *
>
> *From:*Ulf Bjorkengren <ulfbjorkengren@geotab.com
> <mailto:ulfbjorkengren@geotab.com>>
> *Sent:* Dienstag, 11. Februar 2020 09:36
> *To:* Magnus Feuer <mfeuer1@jaguarlandrover.com
> <mailto:mfeuer1@jaguarlandrover.com>>
> *Cc:* public-automotive@w3.org <mailto:public-automotive@w3.org>
> *Subject:* Re: Proposal for Remote Procedure Call extensions to VISS.
>
>
>
> Thanks for the explanation.
>
>
>
> I see this as a rather lightweight wrapper on top of VISS(/Gen2)
> that provides a different interface style. Which is fine with me,
> but I am doubtful in it being a formal part of the standard.
>
> I also conclude that this is a different thing than WAMP that
> Gunnar mentioned.
>
>
>
> BR
>
> Ulf
>
>
>
> On Mon, Feb 10, 2020 at 11:03 PM Magnus Feuer
> <mfeuer1@jaguarlandrover.com <mailto:mfeuer1@jaguarlandrover.com>>
> wrote:
>
> I forgot the most important bit, the function call itself:
>
>
>
> call_rpc("Vehicle.Cabin.Door.Row1.Left.Window.SetPosition",
> Position=50);
>
>
>
> The argument (Position) can either be defined locally in the
> RPC definition, as per my previous email, or be a reference /
> anchor to a signal (tree) living somewhere else in the spec
>
>
>
> /Magnus F.
>
>
>
> -------------------
>
> /System Architect Manager/
>
> *Jaguar Land Rover*
>
> *Email*: mfeuer1@jaguarlandrover.com
> <mailto:mfeuer1@jaguarlandrover.com>
> *Mobile*: +1 949 294 7871
>
>
>
> http://www.jaguarlandrover.com/email/jlr.jpg
>
> Jaguar Land Rover North America, LLC
>
> 1450 NW 18th Ave, Portland, OR 97209
>
> -------------------
> Business Details:
> Jaguar Land Rover Limited
> Registered Office: Abbey Road, Whitley, Coventry CV3 4LF
>
> Registered in England No: 1672070
>
>
> This e-mail and any attachments contain confidential
> information for a specific individual and purpose. The
> information is private and privileged and intended solely for
> the use of the individual to whom it is addressed. If you are
> not the intended recipient, please e-mail us immediately. We
> apologise for any inconvenience caused but you are hereby
> notified that any disclosure, copying or distribution or the
> taking of any action in reliance on the information contained
> herein is strictly prohibited.
>
> This e-mail does not constitute an order for goods or services
> unless accompanied by an official purchase order.
>
>
>
> ------------------------------------------------------------------------
>
> *From:*Magnus Feuer <mfeuer1@jaguarlandrover.com
> <mailto:mfeuer1@jaguarlandrover.com>>
> *Sent:* Monday, February 10, 2020 13:52
> *To:* Ulf Bjorkengren <ulfbjorkengren@geotab.com
> <mailto:ulfbjorkengren@geotab.com>>
> *Cc:* public-automotive@w3.org
> <mailto:public-automotive@w3.org><public-automotive@w3.org
> <mailto:public-automotive@w3.org>>
> *Subject:* Re: Proposal for Remote Procedure Call extensions
> to VISS.
>
>
>
>
>
> Ulf,
>
>
>
> The idea is that the function name, and its arguments, live
> outside the VSS spec, driving our JLR principle of "RPC to
> actuate. Signal to sense". We are using a separate YAML file
> format for our service specifications.
>
>
>
> That said, the idea of integrating function names into the VSS
> spec is probably worth exploring, although it may be too much
> feature packing into a single spec.
>
>
>
> An RPC call in a VSS spec file would look something like:
>
>
>
> # Signal to report window position
>
> - Position:
>
> datatype: uint8
>
> type: sensor
>
> min: 0
>
> max: 100
>
> unit: percent
>
> description: Window position. 0 = Fully closed 100 = Fully
> opened.
>
>
>
>
>
> # RPC to actuate window position
>
> - SetPosition:
>
> type: rpc
>
> description: Move the window to a spcific position
>
> arguments:
>
> - TargetPosition:
>
> datatype: uint8
>
> min: 0
>
> max: 100
>
> unit: percent
>
> description: The target position to move the window to.
> 0 = Fully closed 100 = Fully opened.
>
> return:
>
> - Result:
>
> datatype: uint8
>
> description: The result code (from a standard set of
> result codes)
>
>
>
> - CurrentPosition:
>
> datatype: uint8
>
> min: 0
>
> max: 100
>
> unit: percent
>
> description: The position of the window at the start of
> the window move
>
>
>
> Complex arguments (structs and nested structs) would look much
> like a signal tree.
>
>
>
> Thoughts?
>
>
>
> /Magnus F.
>
>
>
>
>
>
>
> -------------------
>
> /System Architect Manager/
>
> *Jaguar Land Rover*
>
> *Email*: mfeuer1@jaguarlandrover.com
> <mailto:mfeuer1@jaguarlandrover.com>
> *Mobile*: +1 949 294 7871
>
>
>
> http://www.jaguarlandrover.com/email/jlr.jpg
>
> Jaguar Land Rover North America, LLC
>
> 1450 NW 18th Ave, Portland, OR 97209
>
> -------------------
> Business Details:
> Jaguar Land Rover Limited
> Registered Office: Abbey Road, Whitley, Coventry CV3 4LF
>
> Registered in England No: 1672070
>
>
> This e-mail and any attachments contain confidential
> information for a specific individual and purpose. The
> information is private and privileged and intended solely for
> the use of the individual to whom it is addressed. If you are
> not the intended recipient, please e-mail us immediately. We
> apologise for any inconvenience caused but you are hereby
> notified that any disclosure, copying or distribution or the
> taking of any action in reliance on the information contained
> herein is strictly prohibited.
>
> This e-mail does not constitute an order for goods or services
> unless accompanied by an official purchase order.
>
>
>
> ------------------------------------------------------------------------
>
> *From:*Ulf Bjorkengren <ulfbjorkengren@geotab.com
> <mailto:ulfbjorkengren@geotab.com>>
> *Sent:* Monday, February 10, 2020 02:20
> *To:* Magnus Feuer <mfeuer1@jaguarlandrover.com
> <mailto:mfeuer1@jaguarlandrover.com>>
> *Cc:* public-automotive@w3.org
> <mailto:public-automotive@w3.org><public-automotive@w3.org
> <mailto:public-automotive@w3.org>>
> *Subject:* Re: Proposal for Remote Procedure Call extensions
> to VISS.
>
>
>
> Hi,
>
>
>
> I think this could be an interesting extension to the standard.
>
> At the same time I see it as a "wrapper" on the standard,
> which I do not think should be part of the normative standard,
> possible a non-normative note or the like.
>
>
>
> I have a few comments on what is presented
> on https://github.com/PDXostc/viss-rpc.
>
> - In "subscribe" calls the path is explicitly used, while in
> "call" calls this is implicit in the "function" parameter
> (which must then by the receiving server be mapped to a path).
> This means every leaf node in the tree would have to have a
> unique function value.
>
> - In the "call" example the "arguments" filed contain the
> format of provided data. This format is known already by the
> server from the VSS metadata of this node. Providing it in the
> call open for the problem of mismatch with the metadata in the
> tree.
>
>
>
> I do not think that neither this nor WAMP, or any other
> pub-sub solution, should replace HTTP and/or WebSocket as
> transports, but rather complement them.
>
>
>
> BR
>
> Ulf
>
>
>
> On Fri, Feb 7, 2020 at 12:45 AM Magnus Feuer
> <mfeuer1@jaguarlandrover.com
> <mailto:mfeuer1@jaguarlandrover.com>> wrote:
>
> All,
>
>
>
> We have been exploring an extended VISS protocol that
> allows for remote procedure calls to be invoked over the
> same websocket that today runs signal pub/sub.
>
> Since we believe this extension may be of use to the wider
> community, we would like to explore the possibility of
> expanding the W3C standard accordingly.
>
>
>
> The proposal, and a working sample implementation, can be
> found at:
>
>
>
> https://github.com/PDXostc/viss-rpc
>
>
>
> All is open sourced under MPLv2.
>
>
>
> This is in no way a completed spec. Things such as nested
> arguments (structs) and callbacks missing, so questions,
> proposals, and criticism would be much appreciated.
>
>
>
> If we come to an agreement that this is the right way
> forward I will make sure that JLR matures code and
> documentation as needed to integrate them into the W3C
> standard.
>
>
>
> Regards,
>
>
>
> /Magnus F.
>
>
>
> -------------------
>
> /System Architect Manager/
>
> *Jaguar Land Rover*
>
> *Email*: mfeuer1@jaguarlandrover.com
> <mailto:mfeuer1@jaguarlandrover.com>
> *Mobile*: +1 949 294 7871
>
>
>
> http://www.jaguarlandrover.com/email/jlr.jpg
>
> Jaguar Land Rover North America, LLC
>
> 1450 NW 18th Ave, Portland, OR 97209
>
> -------------------
> Business Details:
> Jaguar Land Rover Limited
> Registered Office: Abbey Road, Whitley, Coventry CV3 4LF
>
> Registered in England No: 1672070
>
>
> This e-mail and any attachments contain confidential
> information for a specific individual and purpose. The
> information is private and privileged and intended solely
> for the use of the individual to whom it is addressed. If
> you are not the intended recipient, please e-mail us
> immediately. We apologise for any inconvenience caused
> but you are hereby notified that any disclosure, copying
> or distribution or the taking of any action in reliance on
> the information contained herein is strictly prohibited.
>
> This e-mail does not constitute an order for goods or
> services unless accompanied by an official purchase order.
>
>
>
>
>
>
> --
>
> *Ulf Bjorkengren*
>
> *Geotab*
>
> Senior Connectivity Strategist | Ph. D.
>
> Mobile
>
>
>
> +45 53562142
>
> Visit
>
>
>
> www.geotab.com <https://www.geotab.com/>
>
>
>
>
>
>
>
> --
>
> *Ulf Bjorkengren*
>
> *Geotab*
>
> Senior Connectivity Strategist | Ph. D.
>
> Mobile
>
>
>
> +45 53562142
>
> Visit
>
>
>
> www.geotab.com <https://www.geotab.com/>
>
>
>
>
>
>
>
>
> --
> Ulf Bjorkengren
> *Geotab*
> Senior Connectivity Strategist | Ph. D.
> Mobile +45 53562142
> Visit www.geotab.com <https://www.geotab.com/>
>
>
>
--
-----
Rudolf J Streif
CEO/CTO ibeeto
+1.855.442.3386 x700
Received on Tuesday, 11 February 2020 16:28:22 UTC