This gem defines a route in your Rails app for ELB healthchecks. The healthcheck is a piece of Rack middleware that does absolutely nothing, so it is faster than just using the default "/" route.

gem 'aws-healthcheck'

Your Rails app now returns a 200 from /healthcheck.

If ENV['GIT_COMMIT'] is set, the response will also include that value in the body:

{ "commit": "abcdef123456" }