Creating Circuit Breaker with 100 Lines of Code

“If you want to avoid your entire service going down because one component is down, you should use a circuit breaker,” Kevin told me when I try to design one of our microservices. We talked in front of the ramen shop on a cold winter night in New York City in 2019.

I asked him, “What is it exactly, circuit breaker?”, “Dude! It is a popular microservice pattern. Search it up!”

I pull out my phone and start typing “Circuit Breaker.” In brief, it a mechanism that helps improve the resiliency of your services. I thought to myself, I need to understand more about the tool of this. Therefore, I determined to go back that day, do more research, and implement my own circuit breaker version.

Surprise, surprise — as always, I procrastinated. Fast forward 2 years later, I have learned so much about distributed systems, Scala, and functional programming — and I would like to share the what and the how of circuit breaker mechanism. In this article, I would like to share how I created a circuit breaker library using scala and leveraging the concurrent primitive types.

What is Circuit Breaker

Imagine when you request an HTTP call from one service to the other. It may result in multiple conditions. You may get a successful response. However, you may also get a…