I recently needed a friendly to use circuit breaker in a Scala program. What I found was okay, but not nearly good enough for high volume, highly concurrent applications. So I set out to make it better.
After some iterations of changing I realized that the circuit breaker could be combined with other stuff like rate limiting, monitoring and such. Now, three months later, Sentries is ready for the world.Here is an example usage: Please visit Sentries on Githib and let me know what you think.
Update 2012-09-04: Version 0.2 will be available in Maven central around 2012-09-04 18:00 GMT.
Update 2012-10-08: Version 0.3 has just landed in Maven central. Its only feature is the new 'clean()' method on the sentry registry which is useful during testing.
Update 2013-02-06: Version 0.5 is out. This is the first to support Scala 2.10. Breaking change is that all durations are now of type akka.util.Duration or scala.concurrent.duration.Duration (depending on the Scala version) instead of Long.