[jira] [Commented] (ARIES-1108) Discuss a better user experience when dealing with service dependencies.

["Stephan Siano (JIRA)" <ji...@apache.org>]

    [ https://issues.apache.org/jira/browse/ARIES-1108?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=13753372#comment-13753372 ] 

Stephan Siano commented on ARIES-1108:
--------------------------------------

I like the idea (5) because the subsystem implementation kind of provides the root subsystem and the services exported by these bundles are somewhat provided by the root subsystem.

Option 4 might also help in several cases, however not all services are provided by DS or blueprint (although this is good practice).

Option 1 is a long term solution, however I don't know how long it takes till everybody has taken this up (even if it becomes a best practice).

Updating the maven-bundle-plugin probably won't help much. The Export-Service header is generated for blueprint bundles (and those do already work).

The import and export service headers are somehow informational only, and I don't think that changing the semantics of that is a good idea.

What does uninstalling the application modeller mean, are only service requirements not computed or also wiring stuff (pakage imports etc.)?
                
> Discuss a better user experience when dealing with service dependencies.
> ------------------------------------------------------------------------
>
>                 Key: ARIES-1108
>                 URL: https://issues.apache.org/jira/browse/ARIES-1108
>             Project: Aries
>          Issue Type: Brainstorming
>          Components: Subsystem
>            Reporter: John Ross
>
> Currently, Aries Subsystems will compute service requirements and capabilities for Blueprint bundles only. This can be particularly problematic for users with application subsystems having bundles with service dependencies on non-blueprint bundles outside of their control. For example, an application blueprint bundle with a service dependency on EventAdmin will fail to resolve unless the EventAdmin implementation bundle advertises the service capability in some supported way. To get around this, the user must either (1) turn the bundle into a blueprint bundle, (2) add a Provide-Capability header to the bundle's manifest, or (3) provide their own bundle with a Provide-Capability header advertising all of the services of interest.
> The following represents a non-exhaustive list of possibilities.
> (1) Engage bundle providers to include a Provide-Capability header advertising services. This would be particularly helpful for standard OSGi services. Engage OSGi to make this a requirement or best practice.
> (2) Update the maven bundle plugin to generate this header, as it currently does for the Export-Service header.
> (3) Support Import-Service and Export-Service headers in Aries Subsystems. These headers are already generated by the maven bundle plugin.
> (4) Support DS in Aries Subsystems.
> (5) Add some sort of service listener to Aries Subsystems that will ensure existing services are available as "virtual capabilities" to resolving subsystems.
> Note that in Aries Subsystems 1.0.1-SNAPSHOT+, the ModelledResourceManager service, used to compute service requirements and capabilities, is now optional. This means users can uninstall (or not install) the org.apache.aries.application.modeller bundle in order to disable service resolution.

--
This message is automatically generated by JIRA.
If you think it was sent incorrectly, please contact your JIRA administrators
For more information on JIRA, see: http://www.atlassian.com/software/jira