[jboss-as7-dev] Integration of managed components (projects)

[Brian Stansberry]

On 1/11/11 4:23 AM, Heiko Braun wrote:
>
> I need some clarification on this one:
> http://community.jboss.org/wiki/DomainRequirements
>
> It says:
>
> "31. Projects must have an internal management API, and not be directly
> dependent on JMX for their management API.
> 32. Projects must maintain a management API wrapper over their internal
> management API.
> This is an integration requirement."
>
>

(I'm reordering your questions a bit to let me make a more coherent 
response.)

> - What does management API wrapper mean in this case?

This is the integration code that implements the AS 7 management SPIs 
and knows how to talk to the subsystem's internal managment API. See below.

> - How do they interface each other (i.e. notification of state changes)?
>

The best place to start looking to see how we see this working is:

https://github.com/bstansberry/jboss-as/tree/detyped2/controller/src/main/java/org/jboss/as/controller

(Note that classes named NewXXX are meant to be renamed to XXX once we 
shift over to the detyped representation of the management model.)

A module that extends the core capabilities of the AS needs to implement 
the NewExtension interface. So all the existing subsystems like JMX, 
web, osgi, messaging implement Extension. When we start the NewExtension 
we pass NewExtensionContext to initialize(). The extension can use that 
interface to register the subsystems it exposes (usually just one). You 
can follow the interfaces to see what goes on. Basically, the subsystem 
must expose a tree-structured management model. Each node in the tree 
can have attributes and operations. The subsystem registers handlers for 
all operations it exposes.  Those handlers are what would delegate back 
to whatever internal management API the project exposes.

Notifications -- these are a glaring hole in the SPI. We need to add 
them in. I think it should be relatively straightforward. Notifications 
would have an address in the tree (like everything else), a String name, 
and a detyped payload.


 > - What's the association between the domain and a managed component?

I'm not sure what you're asking, but I'll answer with something 
hopefully useful. :-)

An extension interacts with AS 7 at two levels: the domain (running 
inside a DomainController or HostController) and the server (running 
inside a standalone or domain-managed server).

Inside the DomainController/HostController, the interaction is pretty 
simple. The DC maintains a data structure representing the persistent 
domain configuration (i.e. what's in domain.xml). An extension needs to 
provide operation handlers that can update it's portion of that data 
structure.

Each server also maintains an equivalent data structure that represents 
its configuration. That's either a) in domain mode, a non-persistent 
view of the translation from domain.xml + host.xml to the server's 
configuration, or b) in standalone mode, a representation of the 
persistent standalone.xml config.  (The data structure is the same in 
either case, and the extension doesn't care whether it's domain mode or 
standalone mode.) On the server, an extension needs to provide operation 
handlers that can update it's portion of that data structure. *Plus*, 
those handlers need to be able create/remove/interact with the actual 
runtime services the extension supports. (E.g. read and return some 
metric, change the size of a thread pool, start a new connector, etc.)

>
> Ike
>
>
>
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-- 
Brian Stansberry
Principal Software Engineer
JBoss by Red Hat