Hmm, not sure I understand why you put code in one image and then use it as a volume for other containers. Why not run directly from the volume with the code?
Composability whilst maintaining a monolith codebase. The code in its single imageis used in 3 different environments, without including any runtimes that those environments might not need, keeping the image small. At the same time all code can be kept in a single git repository.
