c# - 使用 Entity Framework 和 MySQL 实现 MassTransit saga 持久性

Question

我正在使用 MassTransit(使用 RabbitMQ)和 Automatonymous 开发一个传奇。我使用 EntityFramework 作为我的存储引擎，使用 MySQL 作为我的数据库。每次我尝试运行 saga 并将其状态存储在数据库中时，EF 和 MySQL 的组合都会引发异常。该问题可以通过 this 重现示例应用程序并使用 MySQL 数据库的连接字符串。抛出的确切异常是:

System.Data.SqlClient.SqlException (0x80131904): A network-related or instance-specific error occurred while establishing a connection to SQL Server. The server was not found or was not accessible. Ve rify that the instance name is correct and that SQL Server is configured to allow remote connections. (provider: Named Pipes Provider, error: 40 - Could not open a connection to SQL Server) ---> Syste m.ComponentModel.Win32Exception (0x80004005): The system cannot find the file specified at System.Data.SqlClient.SqlInternalConnectionTds..ctor(DbConnectionPoolIdentity identity, SqlConnectionString connectionOptions, SqlCredential credential, Object providerInfo, String newPassword, SecureString newSecurePassword, Boolean redirectedUserInstance, SqlConnectionString userConnectionOptions, SessionData reconnectSessionData, DbConnectionPool pool, String accessToken, Boolean applyTra nsientFaultHandling) at System.Data.SqlClient.SqlConnectionFactory.CreateConnection(DbConnectionOptions options, DbConnectionPoolKey poolKey, Object poolGroupProviderInfo, DbConnectionPool pool, DbConnection owningConn ection, DbConnectionOptions userOptions) at System.Data.ProviderBase.DbConnectionFactory.CreatePooledConnection(DbConnectionPool pool, DbConnection owningObject, DbConnectionOptions options, DbConnectionPoolKey poolKey, DbConnectionOption s userOptions) at System.Data.ProviderBase.DbConnectionPool.CreateObject(DbConnection owningObject, DbConnectionOptions userOptions, DbConnectionInternal oldConnection) at System.Data.ProviderBase.DbConnectionPool.UserCreateRequest(DbConnection owningObject, DbConnectionOptions userOptions, DbConnectionInternal oldConnection) at System.Data.ProviderBase.DbConnectionPool.TryGetConnection(DbConnection owningObject, UInt32 waitForMultipleObjectsTimeout, Boolean allowCreate, Boolean onlyOneCheckConnection, DbConnectionOptio ns userOptions, DbConnectionInternal& connection) at System.Data.ProviderBase.DbConnectionPool.TryGetConnection(DbConnection owningObject, TaskCompletionSource1 retry, DbConnectionOptions userOptions, DbConnectionInternal& connection) at System.Data.ProviderBase.DbConnectionFactory.TryGetConnection(DbConnection owningConnection, TaskCompletionSource1 retry, DbConnectionOptions userOptions, DbConnectionInternal oldConnection, Db ConnectionInternal& connection) at System.Data.ProviderBase.DbConnectionInternal.TryOpenConnectionInternal(DbConnection outerConnection, DbConnectionFactory connectionFactory, TaskCompletionSource1 retry, DbConnectionOptions use rOptions) at System.Data.ProviderBase.DbConnectionClosed.TryOpenConnection(DbConnection outerConnection, DbConnectionFactory connectionFactory, TaskCompletionSource1 retry, DbConnectionOptions userOptions) at System.Data.SqlClient.SqlConnection.TryOpenInner(TaskCompletionSource1 retry) at System.Data.SqlClient.SqlConnection.TryOpen(TaskCompletionSource1 retry) at System.Data.SqlClient.SqlConnection.Open() at System.Data.Entity.Infrastructure.Interception.DbConnectionDispatcher.b__36(DbConnection t, DbConnectionInterceptionContext c) at System.Data.Entity.Infrastructure.Interception.InternalDispatcher1.Dispatch[TTarget,TInterceptionContext](TTarget target, Action2 operation, TInterceptionContext interceptionContext, Action3 executing, Action3 executed) at System.Data.Entity.Infrastructure.Interception.DbConnectionDispatcher.Open(DbConnection connection, DbInterceptionContext interceptionContext) at System.Data.Entity.SqlServer.SqlProviderServices.<>c__DisplayClass33.b__32() at System.Data.Entity.SqlServer.DefaultSqlExecutionStrategy.<>c__DisplayClass1.b__0() at System.Data.Entity.SqlServer.DefaultSqlExecutionStrategy.Execute[TResult](Func1 operation) at System.Data.Entity.SqlServer.DefaultSqlExecutionStrategy.Execute(Action operation) at System.Data.Entity.SqlServer.SqlProviderServices.UsingConnection(DbConnection sqlConnection, Action1 act) at System.Data.Entity.SqlServer.SqlProviderServices.UsingMasterConnection(DbConnection sqlConnection, Action1 act) at System.Data.Entity.SqlServer.SqlProviderServices.CreateDatabaseFromScript(Nullable1 commandTimeout, DbConnection sqlConnection, String createDatabaseScript) at System.Data.Entity.SqlServer.SqlProviderServices.DbCreateDatabase(DbConnection connection, Nullable1 commandTimeout, StoreItemCollection storeItemCollection) at System.Data.Entity.Core.Common.DbProviderServices.CreateDatabase(DbConnection connection, Nullable1 commandTimeout, StoreItemCollection storeItemCollection) at System.Data.Entity.Core.Objects.ObjectContext.CreateDatabase() at System.Data.Entity.Migrations.Utilities.DatabaseCreator.Create(DbConnection connection) at System.Data.Entity.Migrations.DbMigrator.EnsureDatabaseExists(Action mustSucceedToKeepDatabase) at System.Data.Entity.Migrations.DbMigrator.Update(String targetMigration) at System.Data.Entity.Internal.DatabaseCreator.CreateDatabase(InternalContext internalContext, Func3 createMigrator, ObjectContext objectContext) at System.Data.Entity.Internal.InternalContext.CreateDatabase(ObjectContext objectContext, DatabaseExistenceState existenceState) at System.Data.Entity.Database.Create(DatabaseExistenceState existenceState) at System.Data.Entity.CreateDatabaseIfNotExists1.InitializeDatabase(TContext context) at System.Data.Entity.Internal.InternalContext.<>c__DisplayClassf1.<CreateInitializationAction>b__e() at System.Data.Entity.Internal.InternalContext.PerformInitializationAction(Action action) at System.Data.Entity.Internal.InternalContext.PerformDatabaseInitialization() at System.Data.Entity.Internal.LazyInternalContext.<InitializeDatabase>b__4(InternalContext c) at System.Data.Entity.Internal.RetryAction1.PerformAction(TInput input) at System.Data.Entity.Internal.LazyInternalContext.InitializeDatabaseAction(Action1 action) at System.Data.Entity.Internal.LazyInternalContext.InitializeDatabase() at System.Data.Entity.Internal.LazyInternalContext.get_ObjectContext() at System.Data.Entity.Database.BeginTransaction(IsolationLevel isolationLevel) at MassTransit.EntityFrameworkIntegration.Saga.EntityFrameworkSagaRepository1.d__81.MoveNext() --- End of stack trace from previous location where exception was thrown --- at System.Runtime.CompilerServices.TaskAwaiter.ThrowForNonSuccess(Task task) at System.Runtime.CompilerServices.TaskAwaiter.HandleNonSuccessAndDebuggerNotification(Task task) at System.Runtime.CompilerServices.TaskAwaiter.GetResult() at MassTransit.Saga.Pipeline.Filters.QuerySagaFilter2.>-Send>d__6.MoveNext() --- End of stack trace from previous location where exception was thrown --- at System.Runtime.ExceptionServices.ExceptionDispatchInfo.Throw() at MassTransit.Saga.Pipeline.Filters.QuerySagaFilter2.<MassTransit-Pipeline-IFilter<MassTransit-ConsumeContext<TMessage>>-Send>d__6.MoveNext() --- End of stack trace from previous location where exception was thrown --- at System.Runtime.CompilerServices.TaskAwaiter.ThrowForNonSuccess(Task task) at System.Runtime.CompilerServices.TaskAwaiter.HandleNonSuccessAndDebuggerNotification(Task task) at System.Runtime.CompilerServices.TaskAwaiter.GetResult() at MassTransit.Saga.Pipeline.Filters.CorrelationIdMessageFilter1.d__3.MoveNext() --- End of stack trace from previous location where exception was thrown --- at System.Runtime.CompilerServices.TaskAwaiter.ThrowForNonSuccess(Task task) at System.Runtime.CompilerServices.TaskAwaiter.HandleNonSuccessAndDebuggerNotification(Task task) at System.Runtime.CompilerServices.TaskAwaiter.GetResult() at MassTransit.Pipeline.Filters.TeeConsumeFilter1.<>c__DisplayClass7_0.<<Send>b__0>d.MoveNext() --- End of stack trace from previous location where exception was thrown --- at System.Runtime.CompilerServices.TaskAwaiter.ThrowForNonSuccess(Task task) at System.Runtime.CompilerServices.TaskAwaiter.HandleNonSuccessAndDebuggerNotification(Task task) at System.Runtime.CompilerServices.TaskAwaiter.GetResult() at MassTransit.Pipeline.Filters.TeeConsumeFilter1.d__7.MoveNext() --- End of stack trace from previous location where exception was thrown --- at System.Runtime.CompilerServices.TaskAwaiter.ThrowForNonSuccess(Task task) at System.Runtime.CompilerServices.TaskAwaiter.HandleNonSuccessAndDebuggerNotification(Task task) at System.Runtime.CompilerServices.TaskAwaiter.GetResult() at MassTransit.Pipeline.Filters.MessageConsumeFilter1.<MassTransit-Pipeline-IFilter<MassTransit-ConsumeContext>-Send>d__7.MoveNext() --- End of stack trace from previous location where exception was thrown --- at System.Runtime.ExceptionServices.ExceptionDispatchInfo.Throw() at MassTransit.Pipeline.Filters.MessageConsumeFilter1.-Send>d__7.MoveNext() --- End of stack trace from previous location where exception was thrown --- at System.Runtime.CompilerServices.TaskAwaiter.ThrowForNonSuccess(Task task) at System.Runtime.CompilerServices.TaskAwaiter.HandleNonSuccessAndDebuggerNotification(Task task) at System.Runtime.CompilerServices.TaskAwaiter.GetResult() at MassTransit.Pipeline.Filters.DeserializeFilter.d__4.MoveNext() --- End of stack trace from previous location where exception was thrown --- at System.Runtime.CompilerServices.TaskAwaiter.ThrowForNonSuccess(Task task) at System.Runtime.CompilerServices.TaskAwaiter.HandleNonSuccessAndDebuggerNotification(Task task) at System.Runtime.CompilerServices.TaskAwaiter.GetResult() at MassTransit.Pipeline.Filters.RescueReceiveContextFilter`1.-Send>d__5.MoveNext() ClientConnectionId:00000000-0000-0000-0000-000000000000 Error Number:2,State:0,Class:20

如果我使用随 VS 2015 安装的本地数据库而不是 MySQL，那么它工作得很好。它也可以与内存存储配合良好。即使异常表明找不到服务器，我也可以确认它存在并且可以访问，因为示例应用程序在选择连接字符串时首先进行检查并且成功:

using (var connection = new SqlConnection(connectionString))
{
    // It worked, we can save this as our connection string
    return connectionString;
}

问题是否可能是因为它试图使用 SqlClient 访问 MySQL 数据库？

我正在使用 MySQL Server 5.7、EF 6.1.3、MassTransit 3.5.7 和 Automatonymous 3.5.11。

Answer 1

这不是 MassTransit 问题，而是 Entity Framework 问题。应该是这样的:

如何将 Entity Framework 与 MySQL 结合使用。

您的异常清楚地表明:System.Data.SqlClient 正在抛出它。这是 SQL Server 客户端。它还说:

Could not open a connection to SQL Server

您可以引用documentation关于如何配置 EF 和 MySQL。一般来说，您需要安装 MySql.Data.Entity NuGet 包并告诉 EF 您正在使用 MySQL，然后配置正确的连接字符串:

<connectionStrings>
    <add name="MyContext" providerName="MySql.Data.MySqlClient"
        connectionString="server=localhost;port=3306;database=mycontext;uid=root;password=********"/>
</connectionStrings>
<entityFramework>
    <defaultConnectionFactory type="System.Data.Entity.Infrastructure.SqlConnectionFactory, EntityFramework"/>
    <providers>
        <provider invariantName="MySql.Data.MySqlClient"
            type="MySql.Data.MySqlClient.MySqlProviderServices, MySql.Data.Entity.EF6"/>
        <provider invariantName="System.Data.SqlClient"
            type="System.Data.Entity.SqlServer.SqlProviderServices, EntityFramework.SqlServer"/>
    </providers>
</entityFramework>