Developing a web application is no triffle even if you have the luxury of using images from a public Docker registry, so lets have a look at what we are trying to achieve.
My primary goal is to get familiar with Docker and to do this I want to create a small web application that allows me to manage my book collection. Most of it will be written in Python and use mature frameworks like SQLAlchemy and Falcon to quickly assemble something that is usable.
Now if we really would want to expose all of this to the internet, make it multiuser and scalable, things would quickly get out of hand and become too big for this experiment. So instead of trying to create everything in one go, I'll focus on the core object server with its database back-end along with the server that will augment any book data present in the object store with additional info (the idea is that the front-end of the book app allows you to enter just the ISBN of a book and additional info like title and author will be added by a background process). So from the full solution sketched below, I will omit the containers inside the dashed areas.