[wildfly-dev] EE level java:comp/DefaultDataSource for WildFly 8...

[Eduardo Martins]

+1

There are two other concerns I have with 3):

1) EE binds are done at java:comp or java:module, depending on module/component. Generic blind binding in every instance of a namespace may not be an option for the EE default bindings.

2) Overridden of defaults through jboss app and jboss component xml descriptors, something I have planned for EE Concurrency default binds, may be much more complex to achieve.

I still like the feature, but think it will not help that much for handling EE default bindings.

--E

On Sep 24, 2013, at 4:00 PM, Brian Stansberry <brian.stansberry at redhat.com> wrote:

> Ok, so that's a generic feature.  Seems like a scary generic capability 
> to me, but I'm not as familiar as you guys are with how these namespaces 
> work.
> 
> On 9/24/13 9:54 AM, David M. Lloyd wrote:
>> I think it means the config will continue to work just as it does,
>> except Jeff's error message won't happen anymore.  Bindings in
>> non-global namespaces would materialize in every instance of that namespace.
>> 
>> On 09/24/2013 09:50 AM, Brian Stansberry wrote:
>>> 3) is confusing. If it's naming binding stuff, putting it in naming or
>>> in the relevant subsystem seems more intuitive.
>>> 
>>> What does 1) really mean in terms of config? Something generic? Or
>>> something quite specific that results in the appropriate bindings?
>>> Generic makes me nervous as it opens up a whole new broad feature with
>>> many possible ways it could be broken.
>>> 
>>> I like 1) better than 2) if my concern above can be addressed.
>>> 
>>> On 9/24/13 9:12 AM, David M. Lloyd wrote:
>>>> On 09/24/2013 05:14 AM, Eduardo Martins wrote:
>>>>> Maybe we should create a doc with a reference design, since there are several default EE resources among our subsystems...
>>>>> 
>>>>> IMHO default EE resources should be defined in the related subsystem configuration, otherwise the EE subsystem config will always be changing. In this case there should a configuration in the Datasources subsystem such as:
>>>>> 
>>>>> <subsystem xmlns="urn:jboss:domain:datasources:2.0">
>>>>>           <datasources>
>>>>>           		<default-datasource jndi-name="java:jboss/datasources/ExampleDS" />
>>>>> 		<datasource jndi-name="java:jboss/datasources/ExampleDS" pool-name="ExampleDS" enabled="true" use-java-context="true">
>>>>> 			...
>>>>> 	        </datasource>
>>>>>            	...
>>>>>           </datasources>
>>>>> </subsystem>
>>>>> 
>>>>> For an easier/faster logic to find the default resource, and since we don't officially support linkref on jndi, the subsystem management op that adds the default resource (in this case default-datasource) should create a binder service pointing to a *fixed* jndi name (let's says java:jboss/ee/default/datasource) and inject it with the target resource (in this case the jndi name java:jboss/datasources/ExampleDS).
>>>>> 
>>>>> Then the subsystem should provide a DUP that for EE modules do the required default bindings, in this case java:comp/DefaultDataSource and/or java:module/DefaultDataSource
>>>>> 
>>>>> The subsystem then also needs to take care of the default mapping to the *fixed* jndi name from @Resource injection, this can be accomplished by adding a EEResourceReferenceProcessor to the EEResourceReferenceProcessorRegistry present in DU attachment with key org.jboss.as.ee.component.Attachments.RESOURCE_REFERENCE_PROCESSOR_REGISTRY
>>>> 
>>>> I don't know, I guess I'm running out of opinion on this.
>>>> 
>>>> Here's a list of options:
>>>> 
>>>> 1) Enhance naming subsystem to be able to bind java:comp, java:module,
>>>> java:app names, and put config in that subsystem (modify JMS and other
>>>> subsystems with implicit bindings to do the same)
>>>> 2) Enhance datasources subsystem to include a default datasource
>>>> attribute (== XML element) which, when present, will set up implicit
>>>> bindings for java:comp (and make sure that the config looks/acts
>>>> similarly between JMS, DS, and any other subsystem with implicit bindings)
>>>> 3) Decide it's all the EE subsystem and put implicit bindings in there
>>>> 
>>>> Decision time: GO!
>>>> 
>>> 
>>> 
>> 
>> 
> 
> 
> -- 
> Brian Stansberry
> Principal Software Engineer
> JBoss by Red Hat
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