I think the problem is that the DOtherSide needs to be compiled by hand, which takes a lot of time, but AFAIK this can be dealt with the Docker file. What are the other side effects of using Docker? Does anyone has a working example?
do you mean compile an app through docker? this is done by the CI so look at the code in the github actions
DOtherSide doesn't take long to compile....it could take long if you have pre i5/i7 cpu otherwise it may take a minute or two. But again....if you compile it once you're done. Just put its compilation step in your dockerfile at the beginning in this way if you update you app in later dockerfile istructions you don't have to rebuild everything.
If instead you mean to dockerize a GUI/Qt app (independently that you build it from pure C++ o Nim) just google it (https://forum.qt.io/topic/120349/run-qt-gui-application-inside-docker/13) . The whole idea in case your host system uses X11 it's to expose the host X11 socket to the docker container and make the dockerize app to use that X11 socket.