Friday, 13 October, 2017 UTC
Summary
We wrote a very popular blog a little over a year ago, detailing the reasone behind our choice of organizing our microservices codebase in a single repository called a mono repo.
Since then, we've often been asked - how do you set up a CI/CD pipeline for a mono repo? When a code change to the repository triggers CI, how does your CI know which microservice changed so that it can rebuild and test just that service?
In this blog, we will demonstrate how the Shippable platform makes it simple to independently build, test and deploy microservices from a mono repo. For simplicity, we will use a monorepo sample (that you can fork) that consists of just two microservices, and create a CI/CD pipeline with Amazon ECR and ECS.
Scenario
- Our Node.js application has two microservices: a front-end microservice www that makes API calls to a backend API microservice called api. The source code for both microservices is in separate folders in a mono repo.
- Each microservice is packaged as a Docker image during the build process and has its own independent unit tests.
- Each Docker image is pushed to its own Amazon ECR repository. Both images get deployed to a common Amazon ECS cluster.
- Both these microservice share some common code that is maintained in a separate folder in the mono repo.
- A commit to a microservice builds, tests and deploys that specific microservice.
- A commit to the common code builds, tests and deploys both microservices.