Development Environment

Common Developer Pitfalls

Every development environment has its quirks, so here are a few which have been collected by the community:



Developer Builds

Besides the default dist Maven profile, the assemblies project defines a second dev profile which will cause only one allinone distribution to be created. It is already unpacked and ready to be started. Activate the profile using:

mvn clean install -Pdev

The administrative user interface needs nodejs to build and phantomjs for testing purposes. These will be downloaded as prebuilt binaries during the maven build process. If there are no prebuilt binaries for your operating system, you can build the tools manually and then build opencast using the frontend-no-prebuilt maven profile:

mvn clean install -Pdev,frontend-no-prebuilt

Logging During Builds

While building Opencast, the default log level for Opencast modules is WARN. To increase logging for development, edit the log level configuration in docs/log4j/

Building single modules

When working on a single Opencast module, it can be extremely helpful to watch the newly built version and include it automatically in the Opencast OSGi infrastructure. This can be done through the bundle:watch command in Karaf. The workflow would be as follows:

To see this technique in action, you can watch the following short video:

The updated bundles are only available in the currently running Karaf instance. To create a Opencast version that has this changes permanently, you have to run mvn clean install in the the assemblies directory again. Your current instance will be deleted by the new assembly!

In several cases the bundle:watch can bring Karaf in an unstable condition, as dependencies between bundles will not correctly be restored, after the new bundle has been deployed.

Attaching a Remote Debugger to Karaf

To debug a running Opencast system, you can attach a remote debugger in your IDE (Eclipse or NetBeans, i.e.). For that you have to enable the remote debugging in Karaf OSGI server that runs Opencast.

You have to add "debug" as an additional paramenter to the Opencast start script:

bin/start-opencast debug

If you want to enable debug permanently you can export the variable in the shell:

export DEFAULT_JAVA_DEBUG_OPTS='-Xdebug -Xnoagent -Djava.compiler=NONE -Xrunjdwp:transport=dt_socket,server=y,suspend=y,address=5005'

You can connect the remote debugger of your IDE on port 5005.

Enabling debugger for package installations

Albeit you can use the afforemented method for package installations, you can't start debug mode via system services. The recommended way is to enable the debug mode in the setenv file, normally found in:


And add this line:

export KARAF_DEBUG=true

In case you need to change the port for debbuging, you can adding this another line:


Where {{PORT}} is the desired port.

For more information on remote debugging with Karaf you can visit this site.

It is not recommended to enable remote debugging on production systems!

Adding Dummy Capture Agent

In the case that is needed, you can create a dummy capture agent with testing porpurses. To add a dummy CA, go to the API Docs page in Opencast and enter a new capture agent in:


Name: Any name of your desire.


"key": "capture.device.names",
"value": "presentation,presenter"

Click on submit and is ready to go.

Additionaly you can call this REST endpoint directly using CURL for example.