Shopify/semian: :monkey: Resiliency toolkit for Ruby for failing fast

When services are down they typically fail fast with errors like ECONNREFUSED and ECONNRESET which can be rescued in code. However, slow resources fail slowly. The thread serving the request blocks until it hits the timeout for the slow resource. During that time, the thread is doing nothing useful and thus the slow resource has caused a cascading failure by occupying workers and therefore losing capacity. Semian is a library for failing fast in these situations, allowing you to handle errors gracefully. Semian does this by intercepting resource access through heuristic patterns inspired by Hystrix and Release It: .