My suggestion is to build a package installer for your app and use that to build the final image. For example, we use fpm (running in a container) to build .deb

My suggestion is to build a package installer for your app and use that to build the final image. For example, we use fpm (running in a container) to build .deb packages, then we push those to an apt repository (artifactory) and then build images downstream using apt-get. Initially we did a lot of cloning from source and compiling/installing dependencies, but it's very slow, there's a lot of wasted time in rebuilding identical code, and it's hard to provide patches and upgrades to customers.