[FELIX-6090] No way to provide non-override-able instructions to maven-bundle-plugin

• Type: Improvement
• Status: Open
• Priority: Major
• Resolution: Unresolved
• Affects Version/s: maven-bundle-plugin-4.1.0
• Component/s: Maven Bundle Plugin
• Assignee: Unassigned
• Reporter: Ashish Chopra
• Created: 29/Mar/19 11:05
• Updated: 15/Apr/19 07:23

Description

Since the resolution of FELIX-4596, support for appending or prepending the Manifest Headers via bundle-plugin's build instructions exist. maven-scr-plugin leverages that and via FELIX-4595 it now has the support to append the Service-Component header.

However, this takes away the functionality to provide a Header entirelly via the build-instructions for the project POM. Notably for Service-Component header, this becomes important when the OSGi bundle created by the project's POM has to serve as a host-bundle of one or more OSGi fragment-bundles.
If the fragment bundles have their own OSGi components, one way to activate them is via [0] (as discussed at [1] [2]). But due to "append" nature of entries generated by maven-scr-plugin, the final Service-Component header in the MANIFEST looks like [3], which causes Felix SCR to attempt the activation of the OSGi component twice. This causes a (benign) ERROR log-line to appear [4].

I tried going through the changelogs of maven-bundle-plugin and maven-scr-plugin, but couldn't find any further development on this topic.

Raising this JIRA to review the addition of such a capability (maybe enhance maven-bundle-plugin instructions to optionally ignore requests to update headers, or otherwise provide a mechanism to prepend/append 'auto-generated' Service-Component entries to those specified in POM like maven-resources directive for Include-Resource manifest-header)

[0]

<plugin>
  <groupId>org.apache.felix</groupId>
  <artifactId>maven-bundle-plugin</artifactId>
  <extensions>true</extensions>
  <configuration>
    <instructions>
      <Service-Component>
        OSGI-INF/*.xml
      </Service-Component>
    </instructions>
  </configuration>
</plugin>

[1] http://apache-felix.18485.x6.nabble.com/DS-amp-fragments-td5004610.html
[2] https://stackoverflow.com/a/42062399
[3]

Service-Component: OSGI-INF/*.xml,OSGI-INF/com.example.my.package1.Service1.xml,OSGI-INF/com.example.my.package1.Service2.xml,OSGI-INF/com.example.my.package2.Service.xml

[4]

*ERROR* [FelixStartLevel] com.example.my-bundle bundle com.example.my-bundle:1.0.1.SNAPSHOT (331)[com.example.my.package1.Service1] :  Cannot register component (org.osgi.service.component.ComponentException: The component name 'com.example.my.package1.Service1' has already been registered by Bundle 331 (com.example.my-bundle) as Component of Class com.example.my.package1.Service1)
org.osgi.service.component.ComponentException: The component name 'com.example.my.package1.Service1' has already been registered by Bundle 331 (com.example.my-bundle) as Component of Class com.example.my.package1.Service1
    at org.apache.felix.scr.impl.ComponentRegistry.checkComponentName(ComponentRegistry.java:239) [org.apache.felix.scr:2.1.16]
    at org.apache.felix.scr.impl.BundleComponentActivator.loadDescriptor(BundleComponentActivator.java:442) [org.apache.felix.scr:2.1.16]
    at org.apache.felix.scr.impl.BundleComponentActivator.initialize(BundleComponentActivator.java:314) [org.apache.felix.scr:2.1.16]
    at org.apache.felix.scr.impl.BundleComponentActivator.<init>(BundleComponentActivator.java:269) [org.apache.felix.scr:2.1.16]
    at org.apache.felix.scr.impl.Activator.loadComponents(Activator.java:380) [org.apache.felix.scr:2.1.16]
    at org.apache.felix.scr.impl.Activator.access$200(Activator.java:49) [org.apache.felix.scr:2.1.16]
    at org.apache.felix.scr.impl.Activator$ScrExtension.start(Activator.java:264) [org.apache.felix.scr:2.1.16]
    at org.apache.felix.scr.impl.AbstractExtender.createExtension(AbstractExtender.java:196) [org.apache.felix.scr:2.1.16]
    at org.apache.felix.scr.impl.AbstractExtender.modifiedBundle(AbstractExtender.java:169) [org.apache.felix.scr:2.1.16]
    at org.apache.felix.scr.impl.AbstractExtender.modifiedBundle(AbstractExtender.java:49) [org.apache.felix.scr:2.1.16]
    at org.osgi.util.tracker.BundleTracker$Tracked.customizerModified(BundleTracker.java:488)
    at org.osgi.util.tracker.BundleTracker$Tracked.customizerModified(BundleTracker.java:420)
    at org.osgi.util.tracker.AbstractTracked.track(AbstractTracked.java:232)
    at org.osgi.util.tracker.BundleTracker$Tracked.bundleChanged(BundleTracker.java:450)
    at org.apache.felix.framework.EventDispatcher.invokeBundleListenerCallback(EventDispatcher.java:915)
    at org.apache.felix.framework.EventDispatcher.fireEventImmediately(EventDispatcher.java:834)
    at org.apache.felix.framework.EventDispatcher.fireBundleEvent(EventDispatcher.java:516)
    at org.apache.felix.framework.Felix.fireBundleEvent(Felix.java:4817)
    at org.apache.felix.framework.Felix.startBundle(Felix.java:2336)
    at org.apache.felix.framework.Felix.setActiveStartLevel(Felix.java:1539)
    at org.apache.felix.framework.FrameworkStartLevelImpl.run(FrameworkStartLevelImpl.java:308)
    at java.lang.Thread.run(Thread.java:748)