This repo contains the sample code for the talk Infrastructure-as-code: running microservices on AWS with Docker, Terraform, and ECS.

It consists of:

1. An example sinatra-backend microservice that just returns the text "Hello, World". This app includes a Dockerfile to package it as a Docker container.
2. An example rails-frontend microservice that makes an HTTP call to the sinatra-backend and renders the result as HTML. This app includes a Dockerfile to package it as a Docker container.
3. A docker-compose.yml file to deploy both Docker containers so you can see how the two microservices work together in the development environment. To allow the services to talk to each other, we are using Docker Links as a simple "service discovery" mechanism.
4. Terraform templates to deploy both Docker containers on Amazon's EC2 Container Service (ECS) so you can see how the two microservices work together in the production environment. To allow the services to talk to each other, we deploy an Elastic Load Balancer (ELB) in front of each service and use Terraform to pass the ELB URLs between services. We are using the same environment variables as Docker Links, so this acts as a simple "service discovery" mechanism that works in both dev and prod.

Note: This repo is for demonstration purposes only and should NOT be used to run anything important. For production-ready version of these templates and many other types of infrastructure (e.g. using a more robust service discovery mechanism such as Consul), check out Gruntwork.

To run the rails-frontend and sinatra-backend on your local dev box:

1. Install Docker. If you're on OS X, you may also want to install docker-osx-dev, or the apps will take a long time to start up due to the slowness of VirtualBox mounted folders (see A productive development environment with Docker on OS X).
2. docker-compose up
3. Test sinatra-backend by going to http://localhost:4567 (or http://dockerhost:4567 if you're using docker-osx-dev).
4. Test the rails-frontend (and its connectivity to the sinatra-backend) by going to http://localhost:3000 (or http://dockerhost:3000 if you're using docker-osx-dev).

The docker-compose.yml file mounts rails-frontend and sinatra-backend folders as volumes in each Docker image, so any changes you make to the apps on your host OS will automatically be reflected in the running Docker container. This lets you do iterative "make-a-change-and-refresh" style development.

To deploy the microservices to your AWS account, see the terraform-templates README.

By default, docker-compose.yml and the terraform-templates are using the gruntwork/rails-frontend and gruntwork/sinatra-backend Docker images. These are images I pushed to the Gruntwork Docker Hub account to make it easy for you to try this repo quickly. Obviously, in the real world, you'll want to use your own images instead.

Follow Docker's documentation to create your own Docker images and fill in the new image id and tag in:

1. docker-compose.yml: the image attribute for rails_frontend or sinatra_backend.
2. terraform-templates/terraform.tfvars: the rails_frontend_image and rails_frontend_version or sinatra_backend_image and sinatra_backend_version variables.

For more info, check out the talk Infrastructure-as-code: running microservices on AWS with Docker, Terraform, and ECS, including the video and slides. For a deeper look at Terraform, check out the book Terraform: Up & Running.