Persistence

FCQRS uses Akka.Persistence to persist the events. The events are stored in a database. The database is configured via IConfiguration in our walkthroughs we use HOCON configuration. Also by default it is configured to take auto snapshot at every 30 events. The snapshot is used to speed up the recovery of the actor. The events are stored in a journal and the snapshots are stored in a snapshot store. Recovery is the process that actor replays the events from the journal and applies them to the state of the actor.

Serialization

You can configure the serialization of the events and commands. By default FCQRS uses a custom json serializer based on FSharp.SystemText.Json. The FCQRS.Serialization module provides the following functions for JSON serialization:

• encode - Serializes an object to a JSON string
• decode - Deserializes a JSON element to a strongly-typed object
• encodeToBytes - Serializes an object to a UTF-8 byte array
• decodeFromBytes - Deserializes a byte array to a strongly-typed object

Example usage:

// Serialize to JSON string
let json = Serialization.encode exampleObject

// Deserialize from JSON string
let decoded = Serialization.decode<{| Name: string; Value: int |}> json

In the hocon file you can see it configured

      serializers {
                json = "Akka.Serialization.NewtonSoftJsonSerializer"
                stj = "FCQRS.ActorSerialization+STJSerializer, FCQRS"
           }
           serialization-bindings {
                "System.Object" = json
                "FCQRS.Common+ISerializable, FCQRS" = stj
           }