refactor: move putting snapshots from Get to Put

the-avid-engineer · the-avid-engineer · commit b6c57905b9d9 · 2021-09-26T11:32:27.000-07:00
this is the final piece for allowing snapshot-only mode :) it also makes all of the sense in the world
diff --git a/EntityDb.Abstractions/Transactions/ITransactionCommand.cs b/EntityDb.Abstractions/Transactions/ITransactionCommand.cs
@@ -10,6 +10,16 @@ namespace EntityDb.Abstractions.Transactions
     /// <typeparam name="TEntity">The type of entity to be modified.</typeparam>
     public interface ITransactionCommand<TEntity>
     {
+        /// <summary>
+        /// A snapshot of the entity before the command.
+        /// </summary>
+        TEntity? PreviousSnapshot { get; }
+
+        /// <summary>
+        /// A snapshot of the entity after the command.
+        /// </summary>
+        TEntity NextSnapshot { get; }
+
         /// <summary>
         /// The id of the entity.
         /// </summary>
diff --git a/EntityDb.Common.Tests/Transactions/TransactionTestsBase.cs b/EntityDb.Common.Tests/Transactions/TransactionTestsBase.cs
@@ -406,6 +406,8 @@ public async Task GivenReadOnlyMode_WhenPuttingTransaction_ThenThrow()
                 {
                         new TransactionCommand<TransactionEntity>
                         (
+                            default,
+                            default!,
                             Guid.NewGuid(),
                             0,
                             new DoNothing(),
@@ -441,6 +443,8 @@ static ITransaction<TransactionEntity> NewTransaction(Guid transactionId)
                     {
                         new TransactionCommand<TransactionEntity>
                         (
+                            default,
+                            default!,
                             Guid.NewGuid(),
                             0,
                             new DoNothing(),
@@ -482,6 +486,8 @@ public async Task GivenNonUniqueVersionNumbers_WhenInsertingCommands_ThenReturnF
                 {
                     new TransactionCommand<TransactionEntity>
                     (
+                        default,
+                        default!,
                         entityId,
                         previousVersionNumber,
                         new DoNothing(),
@@ -491,6 +497,8 @@ public async Task GivenNonUniqueVersionNumbers_WhenInsertingCommands_ThenReturnF
                     ),
                     new TransactionCommand<TransactionEntity>
                     (
+                        default,
+                        default!,
                         entityId,
                         previousVersionNumber,
                         new DoNothing(),
@@ -532,6 +540,8 @@ static ITransaction<TransactionEntity> NewTransaction(Guid entityId, ulong previ
                     {
                         new TransactionCommand<TransactionEntity>
                         (
+                            default,
+                            default!,
                             entityId,
                             previousVersionNumber,
                             new DoNothing(),
@@ -581,6 +591,8 @@ public async Task GivenNonUniqueSubversionNumbers_WhenInsertingFacts_ThenReturnF
                 {
                     new TransactionCommand<TransactionEntity>
                     (
+                        default,
+                        default!,
                         entityId,
                         0,
                         new DoNothing(),
@@ -630,6 +642,8 @@ public async Task GivenNonUniqueLeases_WhenInsertingLeaseDocuments_ThenReturnFal
                 {
                     new TransactionCommand<TransactionEntity>
                     (
+                        default,
+                        default!,
                         Guid.NewGuid(),
                         0,
                         new DoNothing(),
@@ -642,6 +656,8 @@ public async Task GivenNonUniqueLeases_WhenInsertingLeaseDocuments_ThenReturnFal
                     ),
                     new TransactionCommand<TransactionEntity>
                     (
+                        default,
+                        default!,
                         Guid.NewGuid(),
                         0,
                         new DoNothing(),
diff --git a/EntityDb.Common/Entities/EntityRepository.cs b/EntityDb.Common/Entities/EntityRepository.cs
@@ -5,6 +5,7 @@
 using EntityDb.Common.Queries;
 using System;
 using System.Diagnostics.CodeAnalysis;
+using System.Linq;
 using System.Threading.Tasks;
 
 namespace EntityDb.Common.Entities
@@ -49,16 +50,26 @@ public async Task<TEntity> Get(Guid entityId)
 
             entity = entity.Reduce(facts);
 
-            if (_serviceProvider.ShouldCache(snapshot, entity) && _snapshotRepository != null)
-            {
-                await _snapshotRepository.PutSnapshot(entityId, entity);
-            }
-
             return entity;
         }
 
         public Task<bool> Put(ITransaction<TEntity> transaction)
         {
+            if (_snapshotRepository != null)
+            {
+                var lastCommands = transaction.Commands
+                    .GroupBy(command => command.EntityId)
+                    .Select(group => group.Last());
+
+                foreach (var lastCommand in lastCommands)
+                {
+                    if (_serviceProvider.ShouldCache(lastCommand.PreviousSnapshot, lastCommand.NextSnapshot))
+                    {
+                        _snapshotRepository.PutSnapshot(lastCommand.EntityId, lastCommand.NextSnapshot);
+                    }
+                }
+            }
+
             return _transactionRepository.PutTransaction(transaction);
         }
 
diff --git a/EntityDb.Common/Transactions/TransactionBuilder.cs b/EntityDb.Common/Transactions/TransactionBuilder.cs
@@ -60,6 +60,8 @@ private void AddTransactionCommand(Guid entityId, ICommand<TEntity> command)
 
             _transactionCommands.Add(new TransactionCommand<TEntity>
             (
+                previousEntity,
+                nextEntity,
                 entityId,
                 previousVersionNumber,
                 command,
diff --git a/EntityDb.Common/Transactions/TransactionCommand.cs b/EntityDb.Common/Transactions/TransactionCommand.cs
@@ -5,7 +5,17 @@
 
 namespace EntityDb.Common.Transactions
 {
-    internal sealed record TransactionCommand<TEntity>(Guid EntityId, ulong ExpectedPreviousVersionNumber, ICommand<TEntity> Command, ITransactionFact<TEntity>[] Facts, ILease[] DeleteLeases, ILease[] InsertLeases) : ITransactionCommand<TEntity>
+    internal sealed record TransactionCommand<TEntity>
+    (
+        TEntity? PreviousSnapshot,
+        TEntity NextSnapshot,
+        Guid EntityId,
+        ulong ExpectedPreviousVersionNumber,
+        ICommand<TEntity> Command,
+        ITransactionFact<TEntity>[] Facts,
+        ILease[] DeleteLeases,
+        ILease[] InsertLeases
+    ) : ITransactionCommand<TEntity>
     {
     }
 }

Original file line number	Diff line number	Diff line change
`@@ -406,6 +406,8 @@ public async Task GivenReadOnlyMode_WhenPuttingTransaction_ThenThrow()`
`406`	`406`	`{`
`407`	`407`	`new TransactionCommand<TransactionEntity>`
`408`	`408`	`(`
	`409`	`+ default,`
	`410`	`+ default!,`
`409`	`411`	`Guid.NewGuid(),`
`410`	`412`	`0,`
`411`	`413`	`new DoNothing(),`
`@@ -441,6 +443,8 @@ static ITransaction<TransactionEntity> NewTransaction(Guid transactionId)`
`441`	`443`	`{`
`442`	`444`	`new TransactionCommand<TransactionEntity>`
`443`	`445`	`(`
	`446`	`+ default,`
	`447`	`+ default!,`
`444`	`448`	`Guid.NewGuid(),`
`445`	`449`	`0,`
`446`	`450`	`new DoNothing(),`
`@@ -482,6 +486,8 @@ public async Task GivenNonUniqueVersionNumbers_WhenInsertingCommands_ThenReturnF`
`482`	`486`	`{`
`483`	`487`	`new TransactionCommand<TransactionEntity>`
`484`	`488`	`(`
	`489`	`+ default,`
	`490`	`+ default!,`
`485`	`491`	`entityId,`
`486`	`492`	`previousVersionNumber,`
`487`	`493`	`new DoNothing(),`
`@@ -491,6 +497,8 @@ public async Task GivenNonUniqueVersionNumbers_WhenInsertingCommands_ThenReturnF`
`491`	`497`	`),`
`492`	`498`	`new TransactionCommand<TransactionEntity>`
`493`	`499`	`(`
	`500`	`+ default,`
	`501`	`+ default!,`
`494`	`502`	`entityId,`
`495`	`503`	`previousVersionNumber,`
`496`	`504`	`new DoNothing(),`
`@@ -532,6 +540,8 @@ static ITransaction<TransactionEntity> NewTransaction(Guid entityId, ulong previ`
`532`	`540`	`{`
`533`	`541`	`new TransactionCommand<TransactionEntity>`
`534`	`542`	`(`
	`543`	`+ default,`
	`544`	`+ default!,`
`535`	`545`	`entityId,`
`536`	`546`	`previousVersionNumber,`
`537`	`547`	`new DoNothing(),`
`@@ -581,6 +591,8 @@ public async Task GivenNonUniqueSubversionNumbers_WhenInsertingFacts_ThenReturnF`
`581`	`591`	`{`
`582`	`592`	`new TransactionCommand<TransactionEntity>`
`583`	`593`	`(`
	`594`	`+ default,`
	`595`	`+ default!,`
`584`	`596`	`entityId,`
`585`	`597`	`0,`
`586`	`598`	`new DoNothing(),`
`@@ -630,6 +642,8 @@ public async Task GivenNonUniqueLeases_WhenInsertingLeaseDocuments_ThenReturnFal`
`630`	`642`	`{`
`631`	`643`	`new TransactionCommand<TransactionEntity>`
`632`	`644`	`(`
	`645`	`+ default,`
	`646`	`+ default!,`
`633`	`647`	`Guid.NewGuid(),`
`634`	`648`	`0,`
`635`	`649`	`new DoNothing(),`
`@@ -642,6 +656,8 @@ public async Task GivenNonUniqueLeases_WhenInsertingLeaseDocuments_ThenReturnFal`
`642`	`656`	`),`
`643`	`657`	`new TransactionCommand<TransactionEntity>`
`644`	`658`	`(`
	`659`	`+ default,`
	`660`	`+ default!,`
`645`	`661`	`Guid.NewGuid(),`
`646`	`662`	`0,`
`647`	`663`	`new DoNothing(),`
Original file line number	Diff line number	Diff line change
`@@ -60,6 +60,8 @@ private void AddTransactionCommand(Guid entityId, ICommand<TEntity> command)`
`60`	`60`
`61`	`61`	`_transactionCommands.Add(new TransactionCommand<TEntity>`
`62`	`62`	`(`
	`63`	`+ previousEntity,`
	`64`	`+ nextEntity,`
`63`	`65`	`entityId,`
`64`	`66`	`previousVersionNumber,`
`65`	`67`	`command,`
Original file line number	Diff line number	Diff line change
`@@ -5,7 +5,17 @@`
`5`	`5`
`6`	`6`	`namespace EntityDb.Common.Transactions`
`7`	`7`	`{`
`8`		`- internal sealed record TransactionCommand<TEntity>(Guid EntityId, ulong ExpectedPreviousVersionNumber, ICommand<TEntity> Command, ITransactionFact<TEntity>[] Facts, ILease[] DeleteLeases, ILease[] InsertLeases) : ITransactionCommand<TEntity>`
	`8`	`+ internal sealed record TransactionCommand<TEntity>`
	`9`	`+ (`
	`10`	`+ TEntity? PreviousSnapshot,`
	`11`	`+ TEntity NextSnapshot,`
	`12`	`+ Guid EntityId,`
	`13`	`+ ulong ExpectedPreviousVersionNumber,`
	`14`	`+ ICommand<TEntity> Command,`
	`15`	`+ ITransactionFact<TEntity>[] Facts,`
	`16`	`+ ILease[] DeleteLeases,`
	`17`	`+ ILease[] InsertLeases`
	`18`	`+ ) : ITransactionCommand<TEntity>`
`9`	`19`	`{`
`10`	`20`	`}`
`11`	`21`	`}`