Keyboard shortcuts

Press ← or → to navigate between chapters

Press S or / to search in the book

Press ? to show this help

Press Esc to hide this help

Introduction

In this practical, you will deploy the book-related microservice as an orchestration of Docker containers. Micronaut Test Resources is great for local development, but it is not designed for deployment.

You will write a Compose file that includes your databases, your Kafka cluster, and your microservices. Then, you will run it via Docker Compose.

However, before we do that, we will write some end-to-end tests for the integration between the microservice, the database, and the Kafka cluster. This will help us test that the container orchestration is working as intended.

What you should already know

You should be able to:

  • Generate clients from OpenAPI specifications (from Practical 3).

You should be familiar with these concepts from the Week 3 lectures:

  • How to write test assertions about the expected eventual state of the system using Awaitility.

You should be familiar with these concepts from the Week 5 lectures:

  • The differences between containerisation and virtualisation.
  • The basic syntax of a Dockerfile, and how Docker images are structured in layers.
  • The core elements of a Compose file, and the differences between bind mounts and volumes.

What you will learn

  • How to use clients generated from OpenAPI specifications for end-to-end testing.
  • How to write a Compose file that orchestrates several Micronaut applications into a single deployable unit.
  • How to test that the container orchestration is working as intended via end-to-end tests.

What you will need

  • Java 17 or newer: install from Adoptium.
  • An IDE with Gradle and Java support: in this worksheet, we discuss IntelliJ IDEA.
  • A local installation of Docker Desktop. Ensure Docker Desktop is running before you start this practical.
    • Note: if using a lab machine, you will need to boot Windows as Docker Desktop is not installed in the Linux image.

If you have a recent installation of Docker Desktop (using Docker Engine 29 or newer), you will need to tell the Docker Java libraries to use version 1.44 of the Docker API, until this issue in Micronaut is fixed. From a Linux/Mac terminal, or from Git Bash in Windows, run this command:

echo api.version=1.44 > $HOME/.docker-java.properties

If you do not have Git Bash on Windows, you can run this from PowerShell instead:

"api.version=1.44" | set-content $HOME/.docker-java.properties -Encoding Ascii

What you will do

You will start from a solution of the Background Processing exercise of Practical 4 (either yours, or our model solution) and work through the rest of the sections.