composum/featurelauncher-nodes repository overview

⁠Composum Launcher Docker Feature Launcher

A docker image with a sling feature launcher that launches a FAR from a Sling Starter 12, but is prepared to deploy more / different features as well as packages / bundles from the filesystem.

Caution: for production use you'll want to create your own docker-image - this is rather meant as and example and a means of easily exploring what Composum can do for you.

Source: https://github.com/ist-dresden/composum-launch/tree/develop/docker/featurelauncher⁠

⁠Usage information

The application defined in the Dockerfile is accessible at port 8080, for debugging port 18080 is opened and JMX is accessible at port 28080. It declares the following volumes:

• /opt/sling/launcher contains the launcher directory, /opt/sling/launcher/logs the log files
• /opt/sling/features-user can contain additional feature archives or features.
• /opt/sling/fileinstall-user can contain bundles or packages for use by the Sling file installer⁠.
• /opt/sling/features-docker/system/ contains the system feature in the docker image. The system features can be changed by overriding this directory. The features have to be present at startup time, the fileinstall-user directory is repeatedly scanned. If the features are not embedded in a feature archive, it's necessary to specify a repository with in the environment variable LAUNCHER_OPTS for the docker image.

An example docker-compose file is present at docker-compose.yml⁠.

There are some scripts:

• start.sh⁠ starts a temporary instance in attached mode - all data is deleted when the script is stopped.
• attach.sh⁠ starts a bash in this instance, for debugging.

⁠Internal structure of the Docker-Image

The application relevant directories are below /opt/sling, and the starter uses a user sling (group sling) to start the launcher. These directories are created:

• fileinstall-docker is contained in the docker image and can contain bundles or packages to be installed by the file installer provider⁠.
• fileinstall-user can be used as a volume so that additional bundles / packages can be processed by the file installer provider.
• features-docker is contained in the docker image and can contain various features or feature archives that are installed on startup.
• features-user can be used as a volume to provide additional features or feature archives.
• scripts contains various scripts used during start.

For production use, we suggest to use feature archives (FAR) instead of features to avoid that the launcher has to access the network, and to take care that everything can be loaded without accessing the network. In fact, the feature launcher is configured per default to avoid using an external repository, but it's possible to add an external repository to be able to use features.