[Opensim-dev] dispatcher interface

Fri Dec 19 16:58:46 UTC 2014

It doesn't use other languages. It enables them. It provides an interface
for enabling other languages to access and control scenes. So... all
modifications to opensim are through very traditional region module
interfaces. And... to make it more valuable for people to use, I've built
client-side libraries in perl & python (and provided a number of useful
examples & utilities in both perl and python).

The dispatcher is a lot like a *MUCH* more generalized (and much more
functional) version of the remote administration interface. It would not be
difficult, for example, to replace the remote admin interface with one
based on dispatcher messages.

So the problem Oren refers to is this... if we add a new message type to
the dispatcher, it would be good to enable support for that message in the
client libraries. Nothing will break if you don't. However, it would be
extremely useful to do so.

I like Oren's idea of automating the process. And that would kill two birds
with one stone, so to speak. Creating a specification for the messages that
can be processed into the csharp representation and the client libraries
(which are mostly "mechanical" anyway) would simplify the documentation of
the interface.

--mic

On Fri Dec 19 2014 at 7:33:45 AM Melanie <melanie at t-data.com> wrote:

> This is a very real issue - in the past packages have been refused
> core inclusion and packages have even been removed for using
> languages other than C#. Can of worms here. Do we want to lift the
> requirement, or do we want to have only the C# based dispatcher in
> core but not the clients?
>
> Melanie
>
>
> On 19/12/2014 06:11, Oren Hurvitz wrote:
> > I would also like to see Dispatcher in core: it opens up many interesting
> > possibilities, and it's a good example of things OpenSim can do that SL
> > can't.
> >
> > Adding Dispatcher to core would make it easier to keep it up-to-date
> > whenever the API changes, since any changes to an interface that
> Dispatcher
> > uses would cause a compilation error so it would get fixed immediately.
> >
> > The clients should also go into the main OpenSim repository, because
> > they're strongly coupled with Dispatcher: whenever Dispatcher changes the
> > clients also need to change. If they're stored in a different repository
> > then it's likely that the clients would drift out of sync with the part
> of
> > Dispatcher that's in the main OpenSim repository.
> >
> > There's a challenge with the clients, however: since they're in multiple
> > languages, does that mean that anyone who wants to change Dispatcher also
> > has to know all of these languages, so that they can update the clients?
> > That's a high bar. I think we're looking at a situation similar to the
> > database engines: since most developers only use one database engine
> > (usually SQLite or MySQL), the popular engines are kept up-to-date while
> > less-popular engines (SQL Server, Postgres) aren't updated in a timely
> > manner. Basically, they're only updated when their champion realizes that
> > something is broken and brings them up to spec.
> >
> > I don't mean to create even MORE work for you, Mic, but is it possible to
> > create some sort of client bindings that are automatically generated
> from a
> > common API? That way, perhaps all devs have to know is to run something
> > like "ant rebuild-dispatcher-clients" and they'd get updated immediately.
> > If that's not possible then at least a stern warning in the Dispatcher
> code
> > should exhort developers to try and keep the clients up to date.
> >
> > Oren
> >
> >
> >
> > On Fri, Dec 19, 2014 at 2:29 AM, Diva Canto <diva at metaverseink.com>
> wrote:
> >>
> >>  +1 on this going to core.
> >>
> >> WRT client code, I suggest that you leave it in your github repo and
> point
> >> to it. That way we don't confuse people with having code in other
> languages
> >> in core opensim.
> >>
> >>
> >> On 12/18/2014 4:11 PM, Mic Bowman wrote:
> >>
> >> i've had several requests for the dispatcher interface to be moved into
> >> core. dispatcher package consists of two pieces:
> >>
> >>  dispatcher -- the core modules that implement the message transfer,
> >> message encoding and some of the basic messages (informational messages
> and
> >> messages to create and renew access capabilities).
> >>
> >>  https://github.com/cmickeyb/scisim-addons/tree/master/dispatcher
> >>
> >>  remote control -- a collection of messages that implement a OpenSim
> >> remote scripting API. these messages include some basics for
> >> accessing/creating assets, for getting/setting avatar appearance,
> sending
> >> messages, managing objects in the scene, and managing some of the region
> >> characteristics. there are also messages for registering remote handlers
> >> for touch events. clearly this is just a start (though there is a
> >> surprisingly large number of things you can do with these).
> >>
> >> https://github.com/cmickeyb/scisim-addons/tree/master/rcontrol
> >>
> >>  for more information on what the dispatcher is and why you might want
> to
> >> use it, watch the OSCC presentation
> >> http://www.ustream.tv/recorded/55195110 or take a look at the kinds of
> >> scripts that you can write by looking in the scripts directory of the
> >> rcontrol repository.
> >>
> >>  with all that said...
> >>
> >>  i would like to start the discussion about whether this is useful
> enough
> >> to be moved into core & how that should happen.
> >>
> >>  i don't have a particular stake in whether its moved to core. there are
> >> benefits to both. its easier for me to change for my purposes if if its
> >> outside core and its (much) easier for the community to use it if its in
> >> core. if the community believes there is sufficient value, then we
> should
> >> move it in.
> >>
> >>  if it is not moved inside, i would appreciate suggestions on how to
> >> distribute the libraries. this is an ongoing problem for opensim... how
> to
> >> provide simple access to a dynamic set of region modules. probably a
> bigger
> >> discussion.
> >>
> >>  if we think the dispatcher API should be moved into core, then there
> are
> >> a few questions about how that should happen. clearly the region modules
> >> can be moved into OpenSim/Region/OptionalModules. that's easy. the more
> >> interesting question is where to put the client libraries (these are the
> >> perl & python libraries that are used to build dispatcher clients) and
> the
> >> control scripts that are rather useful for managing a region. I would
> >> propose placing them in a directory under OpenSim/Tools though they
> really
> >> aren't tools in the sense of the other packages in that directory.
> >>
> >>  the final question is about documentation. the api is already
> >> pseudo-self documenting... the API lets you can ask any simulator for
> the
> >> messages it supports & then ask for examples of the messages themselves.
> >> i'm planning to add a "documentation" string for each as well. some
> other
> >> methods for autodoc would be useful though pulling out dispatcher
> >> documentation from within the multitude of existing opensim autodoc
> might
> >> be challenging (not something i have any experience with).
> >>
> >>  --mic
> >>
> >>
> >>
> >>
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