Preparing the Environment for the Application

The environment where an application runs always has a big impact on it. It’s one of the big causes of the so-common statement, “It works on my machine.” Over the years, developers have been creating solutions that try to minimize this as much as possible. These solutions can go from automatically provisioning new clean instances for the application to run, to creating more complete packages where everything the application depends on is included.

We can refer to virtual machines (VMs) or containers as ways to achieve this goal. Both are different solutions to the same problem but have one big thing in common: resource isolation. Both try to isolate an application from the environment around it. There are many reasons for this, from security, to automation, to reliability.

Containers are a modern way of providing a package for an application. Modern software projects use them to provide a single container image that has pretty much all it takes for an application to run.

Here is a definition from Docker’s (a container engine) official website: “A container is a standard unit of software that packages up code and all its dependencies so the application runs quickly and reliably from one computing environment to another.”

In our path to make our application easily deployable, we will create this layer of isolation for our Deno application using Docker.

The end goal is to create an image that developers can use to deploy and test a specific version of the application. To do this with Docker, we need to configure the runtime where our application will run. This is defined in a file called a Dockerfile.

That’s what we’ll learn about next.