[wildfly-dev] a way to obtain local ModelController within javaagent?

[Brian Stansberry]

I was thinking about this yesterday and realized that an MCC accessed this way will be broken following a reload. An extension that obtains an internal client doesn’t have this issue as the entire subsystem goes away and is started again as part of the reload. But something that lives outside that cycle is going to need a different integration.

> On Mar 13, 2017, at 10:08 AM, Brian Stansberry <brian.stansberry at redhat.com> wrote:
> 
> Once you get access to MSC, do not use Services.JBOSS_SERVER_CONTROLLER to get a ModelController to create the client. That method is deprecated and I plan to remove it in the next release (WildFly Core 4 / WildFly 12).
> 
> Use ServiceName.parse("org.wildfly.managment.model-controller-client-factory”) to get a ModelControllerClientFactory and use it to create a client, calling createSuperUserClient.
> 
> Note that if you want that client to work properly in a SecurityManager enabled environment your code will need to have org.jboss.as.controller.security.ControllerPermission#PERFORM_IN_VM_CALL PERFORM_IN_VM_CALL. The security guys added in that requirement for WF Core 3. Note that applies even if you use the deprecated ModelController.createClient method. 
> 
>> On Mar 12, 2017, at 8:32 PM, Stuart Douglas <stuart.w.douglas at gmail.com> wrote:
>> 
>> You can call org.jboss.as.server.CurrentServiceContainer#getServiceContainer() to do this, however it is trickey from a JavaAgent (as the module will not be available from the agent's class loader). 
>> 
>> Unfortunately there is no getting around this, as none of the API classes you need will be available in the module. As I see it you have a few different options:
>> 
>> 1) Use reflection to get hold of this class, and then use reflection to make the calls
>> 2) Create a class that does this directly, and then make sure it is loaded from the server module (which has access to the classes you need).
>> 
>> There may be some other options, but that is all I can think of of the top of my head.
>> 
>> If you want more info on how to implement either of these approaches feel free to ask me on hipchat.
>> 
>> Stuart
>> 
>> On Sat, Mar 11, 2017 at 5:43 PM, John Mazzitelli <mazz at redhat.com> wrote:
>> OK, here's another one where I need some secret magical sauce - hoping someone knows of a technique I can use.
>> 
>> Suppose I have a javaagent installed in a WildFly server (using the standard -javaagent VM argument).
>> 
>> The javaagent would like to talk to the WildFly Server it is co-located with. Since it is in the same VM, the javaagent wants to avoid it looking like a remote call.
>> 
>> But I know of no way to obtain a local ModelController instance to build a client short of injecting some service or subsystem into WildFly itself (something I would like to avoid).
>> 
>> If the javaagent were instead a subsystem extension, it could do something like this:
>> 
>>   InjectedValue<ModelController> mcValue = new InjectedValue<>();
>>   ...
>>   ((ServiceBuilder) bldr).addDependency(Services.JBOSS_SERVER_CONTROLLER, ModelController.class, mcValue);
>>   ...
>>   WHAT_I_WANT = mcValue.getValue().createClient(...)
>> 
>> But obviously, that's no good for something running outside of the WildFly container (albeit in the same JVM).
>> 
>> Any hope at all? I was thinking some trickery on the order of what ByteMan does in order to figure out a way to obtain a local ModelController? But that's a last ditch effort :) Hoping there is something that uses a little less witchcraft.
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> 
> -- 
> Brian Stansberry
> Manager, Senior Principal Software Engineer
> JBoss by Red Hat
> 
> 
> 
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-- 
Brian Stansberry
Manager, Senior Principal Software Engineer
JBoss by Red Hat