Introduction

What good is an application unless it is being used? In today's day and age—when DevOps has become the way of doing software development, when the cloud is the king, and when building microservices is considered the thing to do—a lot of attention is being focused on how applications get packaged, distributed, and deployed in their designated environments.

The Twelve-Factor App methodology has played an instrumental role in defining how a modern Software as a Service (SaaS) application is supposed to be built and deployed. One of the key principles is the separation of environmental configuration definitions from the application and storage of this in the environments. The Twelve-Factor App methodology also favors the isolation and bundling of the dependencies, development versus production parity, and ease of deployment and disposability of the applications, among other things.

Note

The Twelve-Factor App methodology can be found at http://12factor.net/.

The DevOps model also encourages...