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.

The DevOps model also encourages us to have complete ownership of our application, starting from writing and testing the code all the way to building and deploying it. If we are to assume this ownership, we need to ensure that the maintenance and overhead costs are not excessive and won't take away much time from our primary task of developing new features. This can be achieved by having clean, well-defined, and isolated deployable artifacts, which are self-contained, self-executed, and can be deployed in any environment without having to be rebuilt.

The following recipes will walk us through all the necessary steps to achieve the goal of low-effort deployment and maintenance while having clean and elegant code behind it.