Writing jenkins plugin: where is the documentation

To my understanding most if not all of the developers have gone to Jenkins. This will most likely mean that Oracle Hudson will stagnate around the current feature set (unless Oracle decides to either backport new packages or start developing Hudson-only plugins - which could be very likely to deal with their products).

Personally we will go with Jenkins as the Open Source development is more important to us than the Oracle-support available with Hudson.

Edit 2011-05: It appears that Oracle cleans up the plugin structure and makes it easier to write new things. Whether this will affect the above situation is hard to say yet.

I faced a similar problem, and I'll tell you how I went about resolving it.

1. Firstly, there is a "core" library, or engine. This basically runs the show, much as you have already got figured out. It handles things common to every system, from rendering forms dynamical, user and account management, roles, you name it, it does it.

2. Every part of the system is contained within a module. A module has dependencies (other modules that it depends on). For example, the "core" system has Security (users, groups, roles, password policies), Locale, (translations, countries, cultures), File Repository, Email, etc, etc. Each module defines itself using an xml file. The xml file basically specifies the schemas, tables, calculation classes, screen definitions etceteras. These are read in when the application starts if the file date has changed.

3. Customer-specific modules have their own xml files and own DLL. It all plus in and functions accordingly and transparently with the rest of the system. Right down to replacing existing MVC views with custom ones, with custom code and custom view models.

4. If a customer wishes to extend existing functionality, the xml/system provides a method where I can "derive" one module from another. The new module has all the existing functionality, but with the customer's specific requirements in a new DLL and with an extended XML file that can make the modifications. The Caveat is, they can't actually remove existing fields in this system ,but we can extend it and provide entirely new objects and functionality.