Feature: Projections (#27)

* feat: abstractions for projections

* chore: add some doc comments

* wip: checkpoint

* refactor: rebase on feat/better-reducer

* refactor: not nullable, will never be null

* bugfix: add missing base class

* Delete IStatement.cs

* checkpoint

Co-Authored-By: watterssn <[email protected]>

* chore: todos for better way to update the cache

* refactor: account for changes from #29

* feat: finish implementations first pass

* refactor: rename TransactionEntity to TestEntity

(no such thing as non-transaction entity)

* refactor: rename variables to entity snapshots

to be distinct from single entity projection snapshots

* test: add entity snapshot subscriber for all entity snapshot tests

* bugfix: didn't mean to commit this yet

* refactor: better name

* test: generalize snapshot tests to work for projection snapshots as well

* chore: store entity type

* chore: add report generator for easily drilling down through coverage

* chore: clean up coverage a little

* refactor: remove unused method

* wip: coverage test

* test: add coverage for projection repository/subscriber

Co-authored-by: watterssn <[email protected]>

Author: the-avid-engineer

.config/dotnet-tools.json

@@ -0,0 +1,12 @@
+{
+  "version": 1,
+  "isRoot": true,
+  "tools": {
+    "dotnet-reportgenerator-globaltool": {
+      "version": "5.1.2",
+      "commands": [
+        "reportgenerator"
+      ]
+    }
+  }
+}

.gitignore

@@ -1,5 +1,5 @@
 TestResults
-CoverageResults
+CoverageReport
 
 ## Ignore Visual Studio temporary files, build results, and
 ## files generated by popular Visual Studio add-ons.

generate-coverage-report.sh

@@ -0,0 +1,9 @@
+#!/bin/sh
+rm -rf ./TestResults ./CoverageReport
+dotnet tool restore
+dotnet restore EntityDb.sln --locked-mode
+#dotnet test EntityDb.sln --no-restore -c Debug --collect:"XPlat Code Coverage" -r ./TestResults -- DataCollectionRunSettings.DataCollectors.DataCollector.Configuration.Format=opencover
+#dotnet reportgenerator -reports:"./TestResults/**/coverage.opencover.xml" -targetdir:"CoverageReport" -reporttypes:Html -license:"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"
+dotnet test EntityDb.sln --no-restore -c Debug --collect:"XPlat Code Coverage" -r ./TestResults
+dotnet reportgenerator -reports:"./TestResults/**/coverage.cobertura.xml" -targetdir:"CoverageReport" -reporttypes:Html -license:"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"
+open CoverageReport/index.html

src/EntityDb.Abstractions/Projections/IProjectionRepository.cs

@@ -0,0 +1,36 @@
+using EntityDb.Abstractions.Disposables;
+using EntityDb.Abstractions.Snapshots;
+using EntityDb.Abstractions.Transactions;
+using EntityDb.Abstractions.ValueObjects;
+using System.Threading.Tasks;
+
+namespace EntityDb.Abstractions.Projections;
+
+/// <summary>
+///     Encapsulates the snapshot repository for a projection.
+/// </summary>
+/// <typeparam name="TProjection">The type of the projection.</typeparam>
+public interface IProjectionRepository<TProjection> : IDisposableResource
+{
+    /// <summary>
+    ///     The strategy for mapping between projection id and entity id.
+    /// </summary>
+    IProjectionStrategy<TProjection> ProjectionStrategy { get; }
+
+    /// <summary>
+    ///     The backing transaction repository.
+    /// </summary>
+    ITransactionRepository TransactionRepository { get; }
+    
+    /// <summary>
+    ///     The backing snapshot repository.
+    /// </summary>
+    ISnapshotRepository<TProjection> SnapshotRepository { get; }
+
+    /// <summary>
+    ///     Returns the current state of a <typeparamref name="TProjection" />.
+    /// </summary>
+    /// <param name="projectionId">The id of the projection.</param>
+    /// <returns>The current state of a <typeparamref name="TProjection" />.</returns>
+    Task<TProjection> GetCurrent(Id projectionId);
+}

src/EntityDb.Abstractions/Projections/IProjectionRepositoryFactory.cs

@@ -0,0 +1,19 @@
+using System.Threading.Tasks;
+
+namespace EntityDb.Abstractions.Projections;
+
+/// <summary>
+///     Represents a type used to create instances of <see cref="IProjectionRepository{TProjection}" />
+/// </summary>
+/// <typeparam name="TProjection">The type of projection managed by the <see cref="IProjectionRepository{TProjection}" />.</typeparam>
+public interface IProjectionRepositoryFactory<TProjection>
+{
+    /// <summary>
+    ///     Create a new instance of <see cref="IProjectionRepository{TProjection}" />
+    /// </summary>
+    /// <param name="transactionSessionOptionsName">The agent's use case for the transaction repository.</param>
+    /// <param name="snapshotSessionOptionsName">The agent's use case for the snapshot repository.</param>
+    /// <returns>A new instance of <see cref="IProjectionRepository{TProjection}" />.</returns>
+    Task<IProjectionRepository<TProjection>> CreateRepository(string transactionSessionOptionsName,
+        string snapshotSessionOptionsName);
+}

src/EntityDb.Abstractions/Projections/IProjectionStrategy.cs

@@ -0,0 +1,26 @@
+using EntityDb.Abstractions.ValueObjects;
+using System.Threading.Tasks;
+
+namespace EntityDb.Abstractions.Projections;
+
+/// <summary>
+///     Represents a type that can map a projection it to a set of entity ids.
+/// </summary>
+/// <typeparam name="TProjection"></typeparam>
+public interface IProjectionStrategy<in TProjection>
+{
+    /// <summary>
+    ///     Map a projection id to a set of entity ids. 
+    /// </summary>
+    /// <param name="projectionId">The id of the projection.</param>
+    /// <param name="projectionSnapshot">A snapshot of the projection, if one exists. (This can be used to avoid running a query, if one were necessary.)</param>
+    /// <returns>The set of entity ids to query for running the projection.</returns>
+    Task<Id[]> GetEntityIds(Id projectionId, TProjection projectionSnapshot);
+
+    /// <summary>
+    ///     Map an entity id to a set of projection ids.
+    /// </summary>
+    /// <param name="entityId">The id of th entity.</param>
+    /// <returns>The set of projection ids to query for running the projection.</returns>
+    Task<Id[]> GetProjectionIds(Id entityId);
+}

src/EntityDb.Common/Annotations/EntityAnnotation.cs

@@ -1,4 +1,6 @@
 using EntityDb.Abstractions.Annotations;
+using EntityDb.Abstractions.Transactions;
+using EntityDb.Abstractions.Transactions.Steps;
 using EntityDb.Abstractions.ValueObjects;
 
 namespace EntityDb.Common.Annotations;
@@ -10,4 +12,18 @@ internal record EntityAnnotation<TData>
     Id EntityId,
     VersionNumber EntityVersionNumber,
     TData Data
-) : IEntityAnnotation<TData>;
+) : IEntityAnnotation<TData>
+{
+    public static EntityAnnotation<TData> CreateFrom(ITransaction transaction, ITransactionStep transactionStep,
+        TData data)
+    {
+        return new
+        (
+            transaction.Id,
+            transaction.TimeStamp,
+            transactionStep.EntityId,
+            transactionStep.EntityVersionNumber,
+            data
+        );
+    }
+}

src/EntityDb.Common/Disposables/DisposableResourceBaseClass.cs

@@ -1,10 +1,12 @@
 using EntityDb.Abstractions.Disposables;
+using System.Diagnostics.CodeAnalysis;
 using System.Threading.Tasks;
 
 namespace EntityDb.Common.Disposables;
 
 internal class DisposableResourceBaseClass : IDisposableResource
 {
+    [ExcludeFromCodeCoverage(Justification = "All Tests Use DisposeAsync")]
     public virtual void Dispose()
     {
         DisposeAsync().AsTask().Wait();

src/EntityDb.Common/Disposables/DisposableResourceBaseRecord.cs

@@ -1,10 +1,12 @@
 using EntityDb.Abstractions.Disposables;
+using System.Diagnostics.CodeAnalysis;
 using System.Threading.Tasks;
 
 namespace EntityDb.Common.Disposables;
 
 internal record DisposableResourceBaseRecord : IDisposableResource
 {
+    [ExcludeFromCodeCoverage(Justification = "All Tests Use DisposeAsync")]
     public virtual void Dispose()
     {
         DisposeAsync().AsTask().Wait();

src/EntityDb.Common/Entities/IEntity.cs

@@ -15,10 +15,16 @@ public interface IEntity<out TEntity>
     /// <returns>A new instance of <typeparamref name="TEntity" />.</returns>
     abstract static TEntity Construct(Id entityId);
 
+    /// <summary>
+    ///     Returns the id of the entity.
+    /// </summary>
+    /// <returns>The id of this entity.</returns>
+    Id GetId();
+    
     /// <summary>
     ///     Returns the version number of the entity.
     /// </summary>
-    /// <returns></returns>
+    /// <returns>The id of this entity.</returns>
     VersionNumber GetVersionNumber();
 
     /// <summary>