Foldunk is a low-dependency set of infrastructure, examples and tests illustrating a consistent approach to Event-sourced Decision processing against ordered stream stores in F#.

The key consumer of this codebase is the Jet.com production site.

However,the codebase as a whole; particularly the, Samples are intended to achieve a critical secondary goal of sharing/discussing/prototyping usage patterns. As such, it's intended to be feasible to use it in the following contexts:

• a testbed for illustrating and prototyping decision/state processing mechanisms
• sample codebase for both internal and external facing Jet.com training events and talks
• base infrastructure for third party talks / tutorials

Please raise GitHub issues for any questions so others can benefit from the discussion.

• Foldunk.Handler: a store agnostic Decision flow runner that fulfills key request processing objectives as dictated by the requirements of Jet.com's front-end API layer
• Foldunk.EventSum: a scheme for the serializing Events modelled as an F# Discriminated Union with the following capabilities:
  • independent of any specific serializer
  • allowes tagging of Discriminated Union cases with eventType tags in a versionable manner
• Foldunk.EventStore: Production-strength EventStore Adapter instrumented to the degree necessitated by Jet's production monitoring requirements
• Compaction: A pattern employed to optimize command processing by employing in-stream 'snapshot' events with the following properties:
  • no additional roundtrips to the store at either the Load or Sync points in the flow to facilitate snapshotting
  • support (via EventSum) for the maintenance of multiple co-existing snapshot schemas in a given stream
• sufficient logging to be used in a Production context