[Opensim-dev] Suggestion for project organization.

[Michael Cortez]

I'd like to make a suggestion about how the OpenSim project is setup
in trunk for building and get some feedback from ya'll.

Currently if a developer would like to work on a new module for
OpenSim, they have to first decide if they want to work inside trunk
(building their module along with OpenSim in the same build) or if
they want to create a completely separate project that just links to
the DLLs produced from OpenSim's trunk.  I don't know about others,
but I personally tend to want to build and debug using the entire
trunk.

So my new module experience is usually something along the following lines:

* Checkout trunk
* Prebuild
* Load up the project in Visual Studio, add a new project, or simply
add a new file to one of the existing projects (Core or Optional
Modules)
* Add any additional references to the existing or new project that
are needed for my new code
* Work on my code for a while.
* Copy out the relevant files to my own separate code repository

Then at some point I end up updating the checkout with latest trunk,
running prebuild, load up the solution file and cuss because the extra
bits I added for my project are no longer present in the solution
(were overwritten by prebuild.)  At this point I usually then go
modify the huge (and growing) prebuild.xml file to add my own project
in there, so it'll be generated along with the trunk projects each
time I prebuild.

I've also noticed a lot of feature creep of things into trunk of
things that are really optional and not required for either building
or running of OpenSim by a lot of people utilizing trunk -=- but they
are things being worked on by the core developers and are definitely
"nice to have" things.

Here is my suggestion:

1) Create a new top level directory in at /trunk/OpenSimModules to
contain individual module projects that are not required/core modules

2) Create an empty Modules directory at /trunk/OpenSim/Modules/ where
nested SVN projects can be checked out to

3) Each module that is optional, and not truly required for every
OpenSim instance can slowly be migrated into /trunk/OpenSimModules/
for example /trunk/OpenSimModules/FlotsamAssetCache  -- each of these
modules would have their own mini, self contained, prebuild included
in their project directory

4) Patch prebuild so that it allows a wildcard to be specified in the
include path, so the following would be valid:  <? include
file="modules/*/prebuild.xml" ?>  [Note: I have a working hack/patch
that would allow this]

5) Modify the main prebuild.xml file located at
/trunk/OpenSim/prebuild.xml to use this new expanded include
directive.


To use the repository in this new configuration, you would first
checkout a copy of trunk/OpenSim -- or a stable build of your choice
-- you then look through the list of modules within
trunk/OpenSimModules for modules that you would like to use with your
OpenSim instance.  You then do a nested checkout of those individual
modules into your local working directory at /OpenSim/Modules/* {svn
fully supports nested working copies like this.}  You then run
prebuild as normal, which will now scan the OpenSimModules directory
and automatically add any found projects to the nant and Visual Studio
solution/build files.  You then run nant or open the Visual Studio
solution file as normal.


What does this accomplish?

*  It separates out optional modules so that we would be working in an
environment that is more like a "base kernel" with "modules" that you
add in to make distributions, aka the "Linux Distribution model."

* Separating out all the non-required modules makes the core
trunk/OpenSim code easier to understand by new developers.

* This separation will also create a clear dividing line between what
is "core" and what isn't

* It will be easier to "drop-in" 3rd party modules that are not stored
in trunk, for compilation and debugging.  GForge projects could simply
be directly checked out into the /OpenSim/Modules/ folder and would
automatically be included during prebuild with no further
configuration other then just running prebuild again.

* All default builds of OpenSim directly out of trunk/OpenSim will be
slim/light weight distributions because the optional stuff won't be
there.

* Individual modules could now be tagged and assigned version numbers.
 They are also separately checked out and updated, thus making it a
lot easier to update individual modules from the main SVN repository
without also pulling down updates to the core or other modules and
vice'versa {for example if you know the latest AssetCacheX is broken,
but you want to retrieve a core update, you can update core without
also updating that particular cache.}


The downsides?

I could only think of two, so this is where I need the most feedback.
The first being that it requires a little more effort on the part of
developers because you have to do multiple SVN checkouts to get a
"full featured" copy of OpenSim's source.   The second being the
migration of the existing code, and the inevitable discovery of some
code that's too highly coupled to move and the re-factoring necessary
to do so.


Parting notes:

I'd also suggest doing the same for all the Grid & Stand-alone related
components, leaving only the bare essentials in trunk/OpenSim
necessary to make a grid attached instance along with the core
components needed by all modules and grid services.  Thus we would
have something like trunk/OpenSimServers or trunk/OpenSimServices
where the grid services (Asset Server, User Server, etc) would be
moved to, and they in-turn would be checked out into a
trunk/OpenSim/Server/ directory.


Thoughts, comments?
--
Michael Cortez