Book Image

A Developer's Essential Guide to Docker Compose

By : Emmanouil Gkatziouras
Book Image

A Developer's Essential Guide to Docker Compose

By: Emmanouil Gkatziouras

Overview of this book

Software development is becoming increasingly complex due to the various software components used. Applications need to be packaged with software components to facilitate their operations, making it complicated to run them. With Docker Compose, a single command can set up your application and the needed dependencies. This book starts with an overview of Docker Compose and its usage and then shows how to create an application. You will also get to grips with the fundamentals of Docker volumes and network, along with Compose commands, their purpose, and use cases. Next, you will set up databases for daily usage using Compose and, leveraging Docker networking, you will establish communication between microservices. You will also run entire stacks locally on Compose, simulate production environments, and enhance CI/CD jobs using Docker Compose. Later chapters will show you how to benefit from Docker Compose for production deployments, provision infrastructure on public clouds such as AWS and Azure, and wrap up with Compose deployments on said infrastructure. By the end of this book, you will have learned how to effectively utilize Docker Compose for day-to-day development.
Table of Contents (19 chapters)
1
Part 1: Docker Compose 101
6
Part 2: Daily Development with Docker Compose
12
Part 3: Deployment with Docker Compose

Packaging your application with Docker and Compose

It’s time that we moved on to packaging and deploying our application using Compose. In order to achieve this, the requisite is to create a Docker image for our application. Before we go in that direction, we need to adapt our code base so it can run in different environments without having to change the code and generate another image.

Enabling environment configuration

By examining the code base, we can see that certain configurations are subject to change. Redis configuration should be flexible since a Redis server, as long as it is accessible to our code base, can be located everywhere. For this reason, the Redis client will derive the configurations through environment variables. However, if there were no configurations provided, it should fall back to a default configuration.

The following utility function will assist us with this. In the case of no environment variable being provided, a default value will be...