Pre-Requisites

You should have a basic understanding of GraphQL, which you can pick up from this documentation, and from the GraphQL home page.

You should be familiar with, but by no means an expert in, Clojure.

You should have a recent build of Clojure, including the clj command.

You should have an editor or IDE ready to go, set up for editing Clojure code.

A skim of the Lacinia reference documentation (the rest of this manual, outside of this tutorial) is also helpful, or you can follow links provided as we go.

The later chapters use a database stored in a Docker container [1] ; you should download and install Docker and ensure that you can run the docker command.

With those basics installed and ready, we can build an empty project and work from there, but first we’ll talk about the application we will be building.

[1]

A Docker container is the Inception of computers; a container is essentially a light-weight virtual machine that runs inside your computer. To the PostgreSQL server we’ll be running inside the container, it will appear as if the entire computer is running Linux, just as if Linux and PostgreSQL were installed on a bare-metal computer. Docker images are smaller and less demanding than full operating system virtual machines. In fact frequently you will run several interconnected containers together. Docker includes infrastructure for downloading the images from a central repository. Ultimately, it’s faster and easier to get PostgreSQL running inside a container that to install the database onto your computer.