CODEWITHSUNDEEP
maven-2osgi
Hanno Fietz
Hanno Fietz

Reputation: 31360

How can I merge multiple OSGi bundles with BND / Maven-BND-plugin?

I'm using some off-the-shelf OSGi bundles in my application and would like to repackage them together with additional packages that are not yet OSGi compatible into a new bundle.

Case in point is EclipseLink, which is available as several OSGi bundles, most of which are optional, depending on what you want to do. I want to pick those bundles that are relevant for me, add database drivers (for example the MySQl JDBC connector) and repackage them into a new bundle that is easier to deploy.

I'm using the maven-bundle-plugin from Apache Felix. I set up a new Maven project without source code, added the four eclipselink and the mysql connector as dependencies and tried the following:

I'm going to face similar issues with Struts 2. I'm not going to be obsessive about this, and just go with a whole bunch of separate third-party bundles, but if I can package them more neatly, I would really like to. I'm aware that a point of OSGi is modularity, so creating big bundles kind of defeats that, but I feel that if your modules are tightly coupled anyway, you might as well put them into a single bundle.

Of course, I could manually tweak the manifests, but I definitely don't want to.

Upvotes: 2

Views: 3576

Answers (1)

Rich Seller
Rich Seller

Reputation: 84028

As omerkudat says, this is probably not a good practice to encourage, but as you have your reasons, this is a way you could do a poor-man's merge.

Assuming you are handling the OSGi manifest yourself, you only really need to get all the classes from the bundles and jars into the target/classes directory before the package phase.

You can do this with either of the dependency plugin's unpack-dependencies or unpack goals. I'd use the unpack-dependencies if you want to process all the project dependencies (or those following a certain naming patter or in a certain groupId) and the unpack goal if you want to have fine control over the artifacts to be unpacked (at the expense of a verbose POM). I'll assume unpack in my example. Each unpack is output to the project's outputDirectory (i.e. target/classes).

Note this will overwrite duplicate artifacts from each package in the order they're downloaded, so the manifests will be clobbering each other. To ensure your artifacts are managed correctly, I would bind the unpack goal to an early phase so that your src/main/resources are copied on top of the unpacked contents and not overwritten. In the sample below this phase is generate-resources, so it will happen after your local compile. If you need to overwrite any of the classes, use an earlier phase to unpack the dependencies such as generate-sources

My sample below unpacks the contents of junit-3.8.1 and commons-io 1.4 (just the first two dependencies I had declarations for) into target/classes before the project's resources are copied there. Note that the versions are defined in my dependencies section. If you haven't got the bundles/jars declared as dependencies you'll need to declare the version in the artifactItem as well.

<plugin>
  <groupId>org.apache.maven.plugins</groupId>
  <artifactId>maven-dependency-plugin</artifactId>
  <executions>
    <execution>
      <id>unpack</id>
      <phase>generate-resources</phase>
      <goals>
        <goal>unpack</goal>
      </goals>
      <configuration>
        <artifactItems>
          <artifactItem>
            <groupId>junit</groupId>
            <artifactId>junit</artifactId>
            <overWrite>false</overWrite>
            <outputDirectory>${project.build.outputDirectory}</outputDirectory>
          </artifactItem>
          <artifactItem>
            <groupId>commons-io</groupId>
            <artifactId>commons-io</artifactId>
            <overWrite>false</overWrite>
            <outputDirectory>${project.build.outputDirectory}</outputDirectory>
          </artifactItem>
        </artifactItems>
        <overWriteReleases>false</overWriteReleases>
        <overWriteSnapshots>true</overWriteSnapshots>
      </configuration>
    </execution>
  </executions>
</plugin>

Upvotes: 2

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