[Opensim-dev] Proposal: Change module interface to indicate replacable modules

[Frisby, Adam]

Suggested change:

Some modules need to be configurable (eg, groups needs the groups URL) - therefore, provide a standard way of entering configuration variables into a module that can be set at runtime before the module is fully loaded.

As an upside, we could backport that to opensim core, so people can enter opensim.ini settings at first startup. Load the more complicated ones from opensim.ini as a default - but some like the defaultX/defaultY, HTTP port, etc.

My suggestion would be something that resembles this in the module code:

Public void prestart(IConfig defaults) {
	IConfig myModuleConfig = new NiniConfig...
	Configurator config = new Configurator(); // uses STDIO

	int x;
	if(!(x = myModuleConfig['MyModule'].GetInteger('foo'))) {
		// Validation might require better handling...
		while(x < 0 && x > 100) {
		  x = config.GetInteger("Value of foo?:");
		}
		myModuleConfig['MyModule']['x'] = x;
	}
	... wash, rinse, repeat ...

	myModuleConfig.Save('config/mymodule.ini');
}

Maybe we can simplify that down with a bit of cleverness and re-usable functions
(eg using a lambda or delegate to handle the validation callback)

Adam

> -----Original Message-----
> From: opensim-dev-bounces at lists.berlios.de [mailto:opensim-dev-
> bounces at lists.berlios.de] On Behalf Of Teravus Ovares
> Sent: Friday, 10 July 2009 5:05 PM
> To: opensim-dev at lists.berlios.de
> Subject: Re: [Opensim-dev] Proposal: Change module interface to
> indicate replacable modules
> 
> Example:
> 
> Diva created a world map module, but the one in the OpenSimulator
> distribution wouldn't let Diva's module run so she had to create a
> configuration flag to turn the module in the OpenSimulator
> distribution off.   Now, there's a complicated configuration option
> for the world map module where you have to type out the object
> namespace.
> 
> The groups module in OpenSimulator's distribution is a stub.   We do
> not intend people to use it out of the box.   Therefore it makes sense
> to have an implicit way to ensure that it doesn't run when there is a
> replacement loaded.
> 
> Melanie doesn't think the 'replaceable modules' architecture is
> maintainable and so she proposed this idea to solve the 3 goals I had
> for it;
> 
> 1. Explicitly declare opensim core developer's intentions for the
> module to be replaceable and that we intend on users replacing the
> stub with a module that is more full featured
> 
> 2. Be implicit so no configuration files or options need to be managed
> by the end user.   This makes packaging binaries easier.  You tell the
> user to download a dll, and put it in the bin folder.   No need to
> modify the opensim.ini or the config-include folder.   This is a step
> in the direction of a console module downloader and loader.
> 
> 3. Be resource friendly.   Currently even modules that are not running
> are loaded in memory.   The objects are.   They may not be using much
> memory..  but they're still there.
> 
> My method of reaching those goals was to create stub projects in
> separate dlls where the dll contains only the module.  The reason for
> it being a single module in the dll is that it can be overwritten with
> a dll provided by someone else.   I called them the
> ReplaceableModules.    Melanie doesn't think this is maintainable
> though with the number of modules that are stuck in various 'catch
> all' dlls.    I'm open to other solutions as long as they accomplish
> the 3 goals :).    Melanie's solution does accomplish those three
> goals.
> 
> 
> Regards
> 
> Teravus
> 
> 
> 
> On Fri, Jul 10, 2009 at 6:28 PM, Kyle Hamilton<aerowolf at gmail.com>
> wrote:
> > money.
> >
> > -Kyle H
> >
> > On Fri, Jul 10, 2009 at 2:09 PM, Justin
> > Clark-Casey<jjustincc at googlemail.com> wrote:
> >> Melanie wrote:
> >>> The intent of this change is to let a module indicate that it
> wishes
> >>> it's load to be deferred until all modules have been scanned and
> >>> initialized, and to indicate that it wishes to ot be initialized if
> >>> another module has already registered it's interface.
> >>>
> >>> This will allow automatically disabling modules the developer has
> >>> marked as "stub" modules without full functionality, so that
> >>> replacement 3rd party modules can simply be dropped into the binary
> >>> distribution and get picked up and run instead of that stub.
> >>
> >> Could you give an example of what kind of module we'd be talking
> about here?  Wouldn't this apply to all modules anyway
> >> (since in principle it should be possible to replace anything)?
> >>
> >> --
> >> justincc
> >> Justin Clark-Casey
> >> http://justincc.wordpress.com
> >> _______________________________________________
> >> Opensim-dev mailing list
> >> Opensim-dev at lists.berlios.de
> >> https://lists.berlios.de/mailman/listinfo/opensim-dev
> >>
> > _______________________________________________
> > Opensim-dev mailing list
> > Opensim-dev at lists.berlios.de
> > https://lists.berlios.de/mailman/listinfo/opensim-dev
> >
> _______________________________________________
> Opensim-dev mailing list
> Opensim-dev at lists.berlios.de
> https://lists.berlios.de/mailman/listinfo/opensim-dev