OSGI component not being picked up by SCR (ServiceMix)?

Question

I am trying to create an OPS4J PAX config DataSource pre-hook to automate database structure integrity checking and updates via Liquibase. According to this tutorial, all I have to do is mark a PreHook implementation with a @Component annotation giving it a name property and reference that property in the DataSource config, which I have done.

The problem seems to be that the component is never picked by the SCR.

@Component(property = "name=coredbmigrate")
public class LiquibaseMigrator implements PreHook {
    public LiquibaseMigrator() {
        System.out.println();
        System.out.println("PREHOOK INITIALIZED");
        System.out.println();
    }

    @Override
    public void prepare(DataSource dataSource) throws SQLException {
        System.out.println();
        System.out.println("PREHOOK CALLED");
        System.out.println();
    }
}

As you can see, I have added basic outputs to indicate when the component is intatiated and called, and neither of those ever happen.

The generated OSGI-INF/lv.cps.is.ledger.accounts.db.LiquibaseMigrator.xml file:

<?xml version="1.0" encoding="UTF-8"?>
<component name="lv.cps.is.ledger.accounts.db.LiquibaseMigrator">
    <implementation class="lv.cps.is.ledger.accounts.db.LiquibaseMigrator"/>
    <service>
        <provide interface="org.ops4j.pax.jdbc.hook.PreHook"/>
    </service>
    <property name="name" type="String" value="coredbmigrate"/>
</component>

Service-Component header in MANIFEST.MF is also set correctly.

What could be the reason that the component is never instantiated? Or maybe it is but I'm not seeing it?

Answer 1

Do you have the scr feature installed? By default it is not installed and in this case DS components are silently ignored.

When it is installed you can use the scr:* commands to check the status of your components.