Reliable Messaging in the World of Actors

This talk explores patterns and obstacles for reliable messaging in actor-based systems, including message delivery guarantees and idempotency. Its examples come from a system built with F# and Akka.NET, while the discussion is language and platform agnostic.

Syllabus

Intro
How to provide message handling guarantee?
Can we run a reliable system with at-most-once message delivery?
Don't pay for the ferryman version 1
Don't pay for the ferryman version 2
Don't pay for the ferryman version 3
Don't pay for the ferryman version 4
Important assumption: Idempotency
But actors are reactive
Main lesson
Rant about workflow engines & saga managers
Conclusion
Outro