Create some kind of "component" archetecture for TG2

At CodeMash? there was quite a bit of discussion on this topic:

Django user contributed apps are one of the main reasons people use django (another is the django admin).

TurboGears has most of the infrastructure to make this as easy as it is in django, but there have been some reservations about doing it, and we definitely have not created project and social structures to encourage the development of reusable application components.

One thing people have been concerned about is copying these components into the project directory. This is definitely the easy way to do it, and it is the way Django works. But there are potential issues because your project becomes totally divorced from upstream fixes to the app...

We could do some kind of 3-way-merge thing to help this out. Either using code from mercurial, or mercurial itself.

The "obvious" way to accomplish something like this, to me, would be to leverage setuptools (which is likely installed on most machines running TG anyway).

Couldn't we establish a "tg2app" entry point, and then have a loadTGApp() function.

So you would ideally have something like:

RootController?():

blog = loadTGApp('blog_app') wiki = loadTGApp('wiki_app')

the loadTGApp() function (or class or whatever) would search the setuptools entrypoint for apps registering that name, and then load them.

I'm sure it sounds easier than it will end up being, but I think this would be a nice way to handle the "multiple app" problem.

Also, in your "main" app, you could just require the 'blog_app', 'wiki_app', etc. packages and let setuptools get the latest ones for you.

Added a requirements document:

http://docs.turbogears.org/2.0/RoughDocs/SiteComponentRequirements

and a discussion about the requirements:

http://groups.google.com/group/turbogears-trunk/browse_frm/thread/d0eed805e8eac514

We should evaluate silverplate as a potential start on this problem.

Also, we should break this down into some smaller steps if possible.