Docker image for nexus

[Yadunund]

To simplify CI in other repos and for general convenience in trying out nexus, it would be good if we add a github action that publishes a docker image of nexus.

[koonpeng]

While I can easily build a docker image, the way nexus currently works is not well suited for docker.

• We can't load capabilities plugins into containers.
• Docker is not designed for gui applications (assuming demoing nexus includes rviz).
• ROS2/dds discovery does not work well in containers.
  • Not sure about zenoh but most likely you would need a router/static discovery.
• We cannot send work orders from outside the container.
• We cannot easily edit the behavior trees.

Is there an example scenario of the challenges faced in CI of other repos? imo the best way to demo nexus is to make a release of nexus_demo, then users can just install it and try. Docker is still great for deployments, but most likely each deployment will need their own customized image.

[Yadunund]

Thanks for the feedback. Your concerns are valid although the network related ones could be resolved through some configs. Either way, the focus here is to reduce the CI build time of packages outside this repo which depend on the packages here. It would speed up those CI jobs that purely evaluate whether build succeeds.

[koonpeng]

For ci, other repos should install a release, pre-release or nightly build of nexus. In fact, having a ci to publish a docker image would be akin to a nightly (or more frequent) release, I don't think we should do that unless we plan to do a proper release on docker as well.