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fix: a character save commits atomically or not at all #2356

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fix: a character save commits atomically or not at all #2356

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24 changes: 24 additions & 0 deletions src/NosCore.Core/Persistence/IDaoTransactionScope.cs
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@@ -0,0 +1,24 @@
// __ _ __ __ ___ __ ___ ___
// | \| |/__\ /' _/ / _//__\| _ \ __|
// | | ' | \/ |`._`.| \_| \/ | v / _|
// |_|\__|\__/ |___/ \__/\__/|_|_\___|
//

using System;
using System.Threading.Tasks;

namespace NosCore.Core.Persistence
{
// Groups every DAO operation issued on the current async flow into one database
// transaction. Nothing is persisted until CommitAsync; disposing without
// committing rolls everything back.
public interface IDaoTransactionScope
{
IDaoTransaction Begin();
}

public interface IDaoTransaction : IAsyncDisposable
{
Task CommitAsync();
}
}
60 changes: 60 additions & 0 deletions src/NosCore.Database/Hosting/DaoTransactionScope.cs
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@@ -0,0 +1,60 @@
// __ _ __ __ ___ __ ___ ___
// | \| |/__\ /' _/ / _//__\| _ \ __|
// | | ' | \/ |`._`.| \_| \/ | v / _|
// |_|\__|\__/ |___/ \__/\__/|_|_\___|
//

using Microsoft.EntityFrameworkCore;
using Microsoft.EntityFrameworkCore.Storage;
using NosCore.Core.Persistence;
using System;
using System.Threading;
using System.Threading.Tasks;

namespace NosCore.Database.Hosting
{
// Carries the transaction's DbContext to every DAO call on the same async flow:
// the DbContext registration consults this slot before building a fresh context.
// AsyncLocal keeps concurrent saves (Task.WhenAll over sessions) isolated from
// each other.
internal static class AmbientDbContext
{
private static readonly AsyncLocal<DbContext?> Slot = new();

public static DbContext? Current => Slot.Value;

public static void Set(DbContext? context)
{
Slot.Value = context;
}
}

public sealed class DaoTransactionScope(Func<NosCoreContext> contextFactory) : IDaoTransactionScope
{
// Synchronous on purpose: an AsyncLocal written inside an awaited method does
// not flow back to the caller, so the ambient slot must be set before the
// first await of the calling flow.
public IDaoTransaction Begin()
{
var context = contextFactory();
var transaction = context.Database.BeginTransaction();
AmbientDbContext.Set(context);
return new DaoTransaction(context, transaction);
}

private sealed class DaoTransaction(NosCoreContext context, IDbContextTransaction transaction) : IDaoTransaction
{
public Task CommitAsync()
{
return transaction.CommitAsync();
}

public async ValueTask DisposeAsync()
{
AmbientDbContext.Set(null);
await transaction.DisposeAsync();
await context.DisposeAsync();
}
}
}
}
15 changes: 14 additions & 1 deletion src/NosCore.Database/Hosting/PersistenceModule.cs
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Expand Up @@ -37,7 +37,18 @@ public PersistenceModule(Action<ContainerBuilder, Type>? onDtoTypeRegistered = n

protected override void Load(ContainerBuilder builder)
{
builder.RegisterType<NosCoreContext>().As<DbContext>();
// DAOs resolve a fresh DbContext per operation through this registration; when
// a DaoTransactionScope is active on the current async flow they get its
// context instead, so the whole scope commits or rolls back as one.
builder.RegisterType<NosCoreContext>().AsSelf().InstancePerDependency();
builder.Register(c => AmbientDbContext.Current ?? (DbContext)c.Resolve<NosCoreContext>())
.As<DbContext>().InstancePerDependency();
builder.Register(c =>
{
var factory = c.Resolve<Func<NosCoreContext>>();
return new DaoTransactionScope(factory);
})
.As<NosCore.Core.Persistence.IDaoTransactionScope>().SingleInstance();

builder.Register(c => c.Resolve<IEnumerable<IDao<IDto>>>().OfType<IDao<II18NDto>>().ToDictionary(
x => x.GetType().GetGenericArguments()[1], y => y.LoadAll().GroupBy(x => x.Key ?? "")
Expand Down Expand Up @@ -82,6 +93,8 @@ protected override void Load(ContainerBuilder builder)
public static void MirrorTo(IServiceCollection services)
{
services.AddTransient<DbContext, NosCoreContext>();
services.AddSingleton<NosCore.Core.Persistence.IDaoTransactionScope>(sp =>
new DaoTransactionScope(() => sp.GetRequiredService<NosCoreContext>()));

foreach (var mapping in DiscoverDaoMappings())
{
Expand Down
134 changes: 93 additions & 41 deletions src/NosCore.GameObject/Services/SaveService/SaveService.cs
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Expand Up @@ -4,6 +4,7 @@
// |_|\__|\__/ |___/ \__/\__/|_|_\___|
//

using NosCore.Core.Persistence;
using NosCore.Dao.Interfaces;
using NosCore.Data.Dto;
using NosCore.Data.Enumerations.I18N;
Expand All @@ -27,7 +28,8 @@ public class SaveService(IDao<CharacterDto, long> characterDao, IDao<IItemInstan
IDao<CharacterQuestDto, Guid> characterQuestDao,
IDao<CharacterQuestObjectiveDto, Guid> characterQuestObjectiveDao,
IDao<RespawnDto, long> respawnDao, ILogger<SaveService> logger,
ILogLanguageLocalizer<LogLanguageKey> logLanguage)
ILogLanguageLocalizer<LogLanguageKey> logLanguage,
IDaoTransactionScope daoTransactionScope)
: ISaveService
{
public async Task SaveAsync(ClientSession session)
Expand Down Expand Up @@ -67,62 +69,112 @@ public async Task SaveAsync(ClientSession session)
characterDto.SpAdditionPoint = character.SpAdditionPoint;
characterDto.CurrentScriptId = character.CurrentScriptId;

await accountDao.TryInsertOrUpdateAsync(account);
await characterDao.TryInsertOrUpdateAsync(characterDto);
// Every DAO call below shares this scope's transaction: the DAOs swallow
// their own exceptions and report failure through their return value, so
// each result is checked and the commit only happens when all of them
// succeeded. Returning early rolls the whole save back.
void Fail(string operation)
{
logger.LogError(
new InvalidOperationException($"{operation} failed; character save rolled back."),
logLanguage[LogLanguageKey.SAVE_CHARACTER_FAILED], characterId);
}

await using var transaction = daoTransactionScope.Begin();

if (await accountDao.TryInsertOrUpdateAsync(account) == null)
{
Fail("Account upsert");
return;
}

if (await characterDao.TryInsertOrUpdateAsync(characterDto) == null)
{
Fail("Character upsert");
return;
}

var quicklistEntriesToDelete = quicklistEntriesDao
.Where(i => i.CharacterId == characterId)!.ToList()
.Where(i => quicklistEntries.All(o => o.Id != i.Id)).ToList();
await quicklistEntriesDao.TryDeleteAsync(quicklistEntriesToDelete.Select(s => s.Id).ToArray());
await quicklistEntriesDao.TryInsertOrUpdateAsync(quicklistEntries);
if (await quicklistEntriesDao.TryDeleteAsync(quicklistEntriesToDelete.Select(s => s.Id).ToArray()) == null)
{
Fail("QuicklistEntry delete");
return;
}
if (!await quicklistEntriesDao.TryInsertOrUpdateAsync(quicklistEntries))
{
Fail("QuicklistEntry upsert");
return;
}

var itemsToDelete = inventoryItemInstanceDao
.Where(i => i.CharacterId == characterId)!.ToList()
.Where(i => inventoryService.Values.All(o => o.Id != i.Id)).ToList();

// Inventory delete order: child rows first, then parent ItemInstance rows.
await inventoryItemInstanceDao.TryDeleteAsync(itemsToDelete.Select(s => s.Id).ToArray());
await itemInstanceDao.TryDeleteAsync(itemsToDelete.Select(s => s.ItemInstanceId).ToArray());
if (await inventoryItemInstanceDao.TryDeleteAsync(itemsToDelete.Select(s => s.Id).ToArray()) == null)
{
Fail("InventoryItemInstance delete");
return;
}
if (await itemInstanceDao.TryDeleteAsync(itemsToDelete.Select(s => s.ItemInstanceId).ToArray()) == null)
{
Fail("ItemInstance delete");
return;
}

// Inventory insert order: parent ItemInstance rows first so the FK on
// InventoryItemInstance.ItemInstanceId resolves on insert. The DAO swallows
// exceptions and returns false on failure, so we MUST check the result —
// otherwise a silent failure on the ItemInstance insert cascades into a
// confusing FK-violation error on the InventoryItemInstance insert that
// follows. Skipping the child insert keeps the failure mode loud and
// localized to the actual broken layer.
var itemInstancesSaved = await itemInstanceDao
.TryInsertOrUpdateAsync(inventoryService.Values.Select(s => s.ItemInstance).ToArray());
if (!itemInstancesSaved)
// InventoryItemInstance.ItemInstanceId resolves on insert.
if (!await itemInstanceDao.TryInsertOrUpdateAsync(inventoryService.Values.Select(s => s.ItemInstance).ToArray()))
{
logger.LogError(
new InvalidOperationException("ItemInstance batch insert failed; skipping InventoryItemInstance to avoid FK cascade."),
logLanguage[LogLanguageKey.SAVE_CHARACTER_FAILED], session.Character.CharacterId);
Fail("ItemInstance upsert");
return;
}
if (!await inventoryItemInstanceDao.TryInsertOrUpdateAsync(inventoryService.Values.ToArray()))
{
Fail("InventoryItemInstance upsert");
return;
}
await inventoryItemInstanceDao.TryInsertOrUpdateAsync(inventoryService.Values.ToArray());

var staticBonusToDelete = staticBonusDao
.Where(i => i.CharacterId == characterId)!.ToList()
.Where(i => staticBonusList.All(o => o.StaticBonusId != i.StaticBonusId)).ToList();
await staticBonusDao.TryDeleteAsync(staticBonusToDelete.Select(s => s.StaticBonusId));
await staticBonusDao.TryInsertOrUpdateAsync(staticBonusList);
if (await staticBonusDao.TryDeleteAsync(staticBonusToDelete.Select(s => s.StaticBonusId)) == null)
{
Fail("StaticBonus delete");
return;
}
if (!await staticBonusDao.TryInsertOrUpdateAsync(staticBonusList))
{
Fail("StaticBonus upsert");
return;
}

await titleDao.TryInsertOrUpdateAsync(titles);
if (!await titleDao.TryInsertOrUpdateAsync(titles))
{
Fail("Title upsert");
return;
}

var minilandDto = (MinilandDto)minilandProvider.GetMiniland(characterId);
await minilandDao.TryInsertOrUpdateAsync(minilandDto);
if (await minilandDao.TryInsertOrUpdateAsync(minilandDto) == null)
{
Fail("Miniland upsert");
return;
}

var questsToDelete = characterQuestDao
.Where(i => i.CharacterId == characterId)!.ToList()
.Where(i => quests.Values.All(o => o.QuestId != i.QuestId)).ToList();
await characterQuestDao.TryDeleteAsync(questsToDelete.Select(s => s.Id));
var questsSaved = await characterQuestDao.TryInsertOrUpdateAsync(quests.Values);
if (!questsSaved)
if (await characterQuestDao.TryDeleteAsync(questsToDelete.Select(s => s.Id)) == null)
{
logger.LogError(
new InvalidOperationException("CharacterQuest upsert failed; skipping objective upsert to avoid FK cascade."),
logLanguage[LogLanguageKey.SAVE_CHARACTER_FAILED], characterId);
Fail("CharacterQuest delete");
return;
}
if (!await characterQuestDao.TryInsertOrUpdateAsync(quests.Values))
{
Fail("CharacterQuest upsert");
return;
}

Expand Down Expand Up @@ -151,24 +203,24 @@ public async Task SaveAsync(ClientSession session)
live.Id = match.Id;
}
}
var objectivesDeleted = await characterQuestObjectiveDao.TryDeleteAsync(objectivesToDelete);
if (objectivesDeleted == null)
if (await characterQuestObjectiveDao.TryDeleteAsync(objectivesToDelete) == null)
{
logger.LogError(
new InvalidOperationException("CharacterQuestObjective delete failed; skipping objective upsert to avoid orphaned-row conflicts on next save."),
logLanguage[LogLanguageKey.SAVE_CHARACTER_FAILED], characterId);
Fail("CharacterQuestObjective delete");
return;
}
var objectivesSaved = await characterQuestObjectiveDao.TryInsertOrUpdateAsync(liveObjectives);
if (!objectivesSaved)
if (!await characterQuestObjectiveDao.TryInsertOrUpdateAsync(liveObjectives))
{
logger.LogError(
new InvalidOperationException("CharacterQuestObjective upsert failed; quest progress will reset on reconnect."),
logLanguage[LogLanguageKey.SAVE_CHARACTER_FAILED], characterId);
Fail("CharacterQuestObjective upsert");
return;
}

if (!await respawnDao.TryInsertOrUpdateAsync(character.Respawns))
{
Fail("Respawn upsert");
return;
}

await respawnDao.TryInsertOrUpdateAsync(character.Respawns);
await transaction.CommitAsync();
}
catch (Exception e)
{
Expand Down
8 changes: 6 additions & 2 deletions test/NosCore.GameObject.Tests/Services/SaveService/SaveServiceTests.cs
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Expand Up @@ -5,6 +5,7 @@
//

using Microsoft.EntityFrameworkCore;
using Microsoft.EntityFrameworkCore.Diagnostics;
using Microsoft.VisualStudio.TestTools.UnitTesting;
using Moq;
using NosCore.Dao;
Expand All @@ -13,6 +14,7 @@
using NosCore.Data.Enumerations.Map;
using NosCore.Data.StaticEntities;
using NosCore.Database;
using NosCore.Database.Hosting;
using NosCore.Database.Entities;
using NosCore.GameObject.Networking.ClientSession;
using NosCore.GameObject.Services.ItemGenerationService;
Expand Down Expand Up @@ -45,7 +47,8 @@ public async Task SetupAsync()
ItemProvider = TestHelpers.Instance.GenerateItemProvider();

var optionsBuilder = new DbContextOptionsBuilder<NosCoreContext>().UseInMemoryDatabase(
Guid.NewGuid().ToString());
Guid.NewGuid().ToString())
.ConfigureWarnings(w => w.Ignore(InMemoryEventId.TransactionIgnoredWarning));
NosCoreContext ContextBuilder() => new NosCoreContext(optionsBuilder.Options);

var itemInstanceDao = new Dao<ItemInstance, IItemInstanceDto?, Guid>(NullLogger<Dao<ItemInstance, IItemInstanceDto?, Guid>>.Instance, ContextBuilder);
Expand Down Expand Up @@ -76,7 +79,8 @@ public async Task SetupAsync()
characterQuestObjectiveDao,
respawnDao,
NullLogger<NosCore.GameObject.Services.SaveService.SaveService>.Instance,
TestHelpers.Instance.LogLanguageLocalizer);
TestHelpers.Instance.LogLanguageLocalizer,
new DaoTransactionScope(ContextBuilder));
}

[TestMethod]
Expand Down
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