Added Event Store and Versioning related classes for Simple Event Ver…

…sioning patterns talk

Sample/EventsVersioning/Talk/EventsVersioning.Talk.sln

@@ -0,0 +1,16 @@
+
+Microsoft Visual Studio Solution File, Format Version 12.00
+Project("{FAE04EC0-301F-11D3-BF4B-00C04F79EFBC}") = "HotelManagement", "HotelManagement\HotelManagement.csproj", "{8B5F91C2-572B-4B2D-B67B-3EA98584888E}"
+EndProject
+Global
+	GlobalSection(SolutionConfigurationPlatforms) = preSolution
+		Debug|Any CPU = Debug|Any CPU
+		Release|Any CPU = Release|Any CPU
+	EndGlobalSection
+	GlobalSection(ProjectConfigurationPlatforms) = postSolution
+		{8B5F91C2-572B-4B2D-B67B-3EA98584888E}.Debug|Any CPU.ActiveCfg = Debug|Any CPU
+		{8B5F91C2-572B-4B2D-B67B-3EA98584888E}.Debug|Any CPU.Build.0 = Debug|Any CPU
+		{8B5F91C2-572B-4B2D-B67B-3EA98584888E}.Release|Any CPU.ActiveCfg = Release|Any CPU
+		{8B5F91C2-572B-4B2D-B67B-3EA98584888E}.Release|Any CPU.Build.0 = Release|Any CPU
+	EndGlobalSection
+EndGlobal

Sample/EventsVersioning/Talk/HotelManagement/EventStore/EventSerializer.cs

@@ -0,0 +1,11 @@
+using System.Text.Json;
+
+namespace HotelManagement.EventStore;
+
+public class EventSerializer(EventTypeMapping mapping, EventTransformations transformations)
+{
+    public object? Deserialize(string eventTypeName, string json) =>
+        transformations.TryTransform(eventTypeName, json, out var transformed)
+            ? transformed
+            : JsonSerializer.Deserialize(json, mapping.Map(eventTypeName));
+}

Sample/EventsVersioning/Talk/HotelManagement/EventStore/EventTransformations.cs

@@ -0,0 +1,42 @@
+using System.Text.Json;
+
+namespace HotelManagement.EventStore;
+
+public class EventTransformations
+{
+    private readonly Dictionary<string, Func<string, object>> jsonTransformations = new();
+
+    public bool TryTransform(string eventTypeName, string json, out object? result)
+    {
+        if (!jsonTransformations.TryGetValue(eventTypeName, out var transformJson))
+        {
+            result = null;
+            return false;
+        }
+
+        result = transformJson(json);
+        return true;
+    }
+
+    public EventTransformations Register<TEvent>(string eventTypeName, Func<JsonDocument, TEvent> transformJson)
+        where TEvent : notnull
+    {
+        jsonTransformations.Add(
+            eventTypeName,
+            json => transformJson(JsonDocument.Parse(json))
+        );
+        return this;
+    }
+
+    public EventTransformations Register<TOldEvent, TEvent>(string eventTypeName,
+        Func<TOldEvent, TEvent> transformEvent)
+        where TOldEvent : notnull
+        where TEvent : notnull
+    {
+        jsonTransformations.Add(
+            eventTypeName,
+            json => transformEvent(JsonSerializer.Deserialize<TOldEvent>(json)!)
+        );
+        return this;
+    }
+}

Sample/EventsVersioning/Talk/HotelManagement/EventStore/EventTypeMapping.cs

@@ -0,0 +1,20 @@
+namespace HotelManagement.EventStore;
+
+public class EventTypeMapping
+{
+    private readonly Dictionary<string, Type> mappings = new();
+
+    public EventTypeMapping Register<TEvent>(params string[] typeNames)
+    {
+        var eventType = typeof(TEvent);
+
+        foreach (var typeName in typeNames)
+        {
+            mappings.Add(typeName, eventType);
+        }
+
+        return this;
+    }
+
+    public Type Map(string eventType) => mappings[eventType];
+}

Sample/EventsVersioning/Talk/HotelManagement/EventStore/InMemoryEventStore.cs

@@ -0,0 +1,44 @@
+using System.Text.Json;
+
+namespace HotelManagement.EventStore;
+
+public interface IEventStore
+{
+    ValueTask AppendToStream(Guid streamId, IEnumerable<object> newEvents, CancellationToken ct = default);
+    ValueTask<TEvent[]> ReadStream<TEvent>(Guid streamId, CancellationToken ct = default) where TEvent : notnull;
+}
+
+public class InMemoryEventStore: IEventStore
+{
+    private readonly Dictionary<Guid, List<(string EventType, string Json)>> events = new();
+
+    public ValueTask AppendToStream(Guid streamId, IEnumerable<object> newEvents, CancellationToken _ = default)
+    {
+        if (!events.ContainsKey(streamId))
+            events[streamId] = [];
+
+        var serializedEvents = newEvents.Select(e => (e.GetType().FullName!, JsonSerializer.Serialize(e)));
+
+        events[streamId].AddRange(serializedEvents);
+
+        return ValueTask.CompletedTask;
+    }
+
+    public ValueTask<TEvent[]> ReadStream<TEvent>(Guid streamId, CancellationToken _ = default) where TEvent : notnull
+    {
+        var streamEvents = events.TryGetValue(streamId, out var stream)
+            ? stream
+            : [];
+
+        var deserializedEvents = streamEvents
+            .Select(@event =>
+                Type.GetType(@event.EventType, true) is { } clrEventType
+                    ? JsonSerializer.Deserialize(@event.Json, clrEventType)
+                    : null
+            )
+            .Where(e => e != null)
+            .Cast<TEvent>().ToArray();
+
+        return ValueTask.FromResult(deserializedEvents);
+    }
+}

Sample/EventsVersioning/Talk/HotelManagement/EventStore/StreamTransformations.cs

@@ -0,0 +1,35 @@
+namespace HotelManagement.EventStore;
+
+public record EventMetadata(
+    Guid CorrelationId
+);
+
+public record EventData(
+    string EventType,
+    string Data,
+    string MetaData
+);
+
+public class StreamTransformations
+{
+    private readonly List<Func<List<EventData>, List<EventData>>> jsonTransformations = [];
+
+    public List<EventData> Transform(List<EventData> events)
+    {
+        if (!jsonTransformations.Any())
+            return events;
+
+        var result = jsonTransformations
+            .Aggregate(events, (current, transform) => transform(current));
+
+        return result;
+    }
+
+    public StreamTransformations Register(
+        Func<List<EventData>, List<EventData>> transformJson
+    )
+    {
+        jsonTransformations.Add(transformJson);
+        return this;
+    }
+}

Sample/EventsVersioning/Talk/HotelManagement/HotelManagement.csproj

@@ -0,0 +1,9 @@
+<Project Sdk="Microsoft.NET.Sdk">
+
+    <PropertyGroup>
+        <TargetFramework>net8.0</TargetFramework>
+        <ImplicitUsings>enable</ImplicitUsings>
+        <Nullable>enable</Nullable>
+    </PropertyGroup>
+
+</Project>

Workshops/EventDrivenArchitecture/Solutions/05-Consistency/Sagas/Version1-Aggregates/Core/Retry.cs

@@ -17,6 +17,6 @@ public class Retry
                 return TimeSpan.FromMilliseconds(1);
             });
 
-    public Task UntilSucceeds(Func<CancellationToken, ValueTask> handle, CancellationToken token = default) =>
+    public static Task UntilSucceeds(Func<CancellationToken, ValueTask> handle, CancellationToken token = default) =>
         retryPolicy.ExecuteAsync(async ct => await handle(ct), token);
 }