Re: [wildfly-dev] Core and subsystem capabilities and requirements

On 06/23/2014 01:20 PM, Brian Stansberry wrote: > As we continue with our work splitting the WildFly code base into a core > repo and then separate repos related to sets of features that we need to > solidify the contracts between the various features and between features > and the core. > > I've taken a crack at an initial design document on this: see [1]. We > also need to do the practical work of identifying the various > dependencies between our existing subsystems, see [2] for a start on that. > > I'd love to get feedback on this thread regarding the proposed design, > as well as get direct edits on the [2] doc to flesh out the existing > relationships. Here is what jumps out at me at first. • I don't understand the reason to not allow optional dependencies on capabilities. It would be of similar implementation complexity to the suggested permutation implementation, however it would avoid the problem of requiring 2ⁿ permutations for n optional dependencies.

• I don't understand the purpose of binding capability identifiers to subsystem identifiers. It seems plausible to have a subsystem provide, for example, two capabilities now, but allow for a capability to be implemented separately in the future. A concrete example would be the way we ultimately moved Servlet from JBoss Web to Undertow. Ideally we'd only ever depend on the capability, making subsystems completely interchangeable.