BND Workspace Layout and Pomless Builds

Tycho supports building projects that use the BND Workspace Layout.

BND Workspace Layout

A BND Workspace layout build layout usually has the following structure:

root folder - this usually is the root of your project repository
- cnf - configuration folder for general setup
  - build.bnd - main configuration file
  - ext - additional configuration (optional)
- bundle1 - A bundle project
  - bnd.bnd - project configuration file
- bundle2 - Another bundle project
  - bnd.bnd - project configuration file
  - myapp.bndrun - a .bndrun file which can be used to export an executable .jar as part of the build
- ...

Any folder that does not match the layout is ignored.

Pomless Builds

Given the above layout, Tycho now has a good knowledge about what your build artifacts are. In contrast to a traditional maven build where each module has to contain a pom.xml file Tycho can derive most all from your supplied bnd configuration files, so everything is configured there and usually no additional maven configuration is required, therefore this build is completely pomless (no pom.xml), there are only a few steps to consider:

Add a folder called .mvn to the root
Inside the .mvn folder place a file called extensions.xml with the following content:

<?xml version="1.0" encoding="UTF-8"?>
<extensions>
   <extension>
      <groupId>org.eclipse.tycho</groupId>
      <artifactId>tycho-build</artifactId>
      <version>${tycho-version}</version>
   </extension>
</extensions>

create a file called maven.config in the .mvn folder with the following content (adjust the Tycho version accordingly to the latest release!):

-Dtycho-version=4.0.10

You can now run your build with mvn clean verify.

You can check more details in a demo project.

Configure the pomless build

If you want to further configure the build can be done in these ways:

You can specify additional global properties in the .mvn/maven.config.
You can define properties per project properties in the bnd.bnd file pom.model.property.<some property>: true, see the wiki for more details.
You can place a pom.xml in your cnf folder this will then be used as a parent for the aggregator, here you can add additional mojos, profiles and so on. If you want to enable certain things only for some of the projects you can use properties as described in (2) to skip the execution of mojos not relevant for other projects.

Create executable jar

Tycho can also create an executable .jar file of your application based on a .bndrun file containing -runbundles, which you can then deploy and start.

Just add the following line to your .mvn/maven.config file or pass it on the maven commandline:

-Dbndrun.exports=mydemo.app

This automatically searches all your bundles for a file named mydemo.app.bndrun.

If you have a bundle myappbundle which contains mydemo.app.bndrun, then the build would create an executable jar at the following location:

/myappbundle/target/executable/mydemo.app.bndrun.jar

Your build output will look like this:

[INFO] --- tycho-bnd:4.0.11:run (build) @ myappbundle ---
[INFO] Exporting mydemo.app.bndrun ...
[INFO] Exported to .../myappbundle/target/executable/tycho.demo.app.jar

Mixed Builds

You can even combine a BND Workspace and PDE bundles in a build, see demo.

Troubleshooting

Note: All properties in .mvn/maven.config can also be supplied via command line, for example to use a different tycho version use the following command line argument:

mvn clean install -Dtycho-version=5.0.0-SNAPSHOT

This uses the snapshot build which is useful if you build tycho yourself on your local machine and want to test that build.

polyglot.dump.pom

E.g., -Dpolyglot.dump.pom=pom-gen.xml specifies that the generated pom.xml files which tycho polyglot creates is called pom-gen.xml. This might be needed if you have name clashes with existing files in your build.

tycho.pomless.aggregator.names

The command line argument -Dtycho.pomless.aggregator.names=_dummydisabled_ is for handling a rare edge case: In case you have your bnd workspace in a subfolder named bundles, plugins, tests,features, sites,products, or releng then tycho can have problems. The reason is that those names are kind of ‘magic’ names reserved for special usecases. -Dtycho.pomless.aggregator.names=_dummydisabled_ is a workaround to instruct Tycho to ignore those names. You can choose any word like _dummydisabled_, but just make sure you do not have a folder with that name.