Processors dependencies and interactions

[ykryshchuk]

This has to be done most likely as a separate module (processor, like we have processors for different products). The topology processing is not a mandatory function of any configuration server, thus the functionality has to be pluggable. Ideally, other processors have to reuse the topology rocessor stylesheets. That implies, that topology processor must be deliverable as a optional package for configuration server.

Using the pluggable processors and their stylesheets has to be designed properly on configuration server level. That includes classpath resolution (to reuse classes from one processor in other processors) and stylesheets resolution (in order to import the templates between processors).

Currently the external processors may reuse "core" classes and stylesheets, but this is currently done as a quick-hack. We need a concept of dependencies between processors and their resources. The new documentation whould describe the idea and should specify the requirements for processors packaging.

Afterwards, the existing processors and core resources have to be re-factored to satisfy the specification.

The next simple steps are:

• Collect the requirements for processors interactions #9
• Document the conventions for configuration processors packaging #10
• Document the deployment rules for server and processors (also explain the classloading and url resolving) #11
• refactor existing processors (core, pe, cd and stat), also extract existing logging processor #17
• add new topology processor and reuse it in existing processors to resolve topology related data

This solution may affect another issue #4

[ykryshchuk]

one more important item to mention is a ConfigServer ClassLoader #12 , which is actually responsible for loading/sharing classes and resources between the processors.