将asp.net核心自包含Web应用程序部署到Ubuntu。 数据库名称在appsettings.json中存在时为空

Question

我刚刚在Digital Ocean上建立了LAMP服务器VM。 操作系统是Ubuntu 18.04 x64。 MySQL是5.7.23。 我还发布了一个本地文件夹asp.net核心Web应用程序，我已将其设置为Ubuntu 18.04-x64。 我将文件从本地文件夹复制到服务器上的var / MyApp，并在可执行文件上设置chmod + x。 我还更改了MySql root密码并创建了一个名为limboworld的数据库。 我的应用程序设置为在启动时运行所有迁移。 但是，当我用./catchme.bg启动时，我得到以下输出，错误如下所示。

我尝试更改MySql密码以及连接字符串：

"catchmebgContextConnection": "Server=localhost;Database=limboworld;User=root;Password=limboworld;"

至

"catchmebgContextConnection": "Server=localhost;Database=limboworld;Uid=root;Pwd=limboworld;"

info: Microsoft.AspNetCore.DataProtection.KeyManagement.XmlKeyManager[0]
      User profile is available. Using '/root/.aspnet/DataProtection-Keys' as key repository; keys will not be encrypted at rest.
info: Microsoft.EntityFrameworkCore.Infrastructure[10403]
      Entity Framework Core 2.1.11-servicing-32099 initialized 'catchmebgContext' using provider 'Pomelo.EntityFrameworkCore.MySql' with options: MaxPoolSize=128 ServerVersion 5.7.24 MySql
fail: Microsoft.EntityFrameworkCore.Database.Connection[20004]
      An error occurred using the connection to database '' on server 'localhost'.
MySql.Data.MySqlClient.MySqlException (0x80004005): Access denied for user 'root'@'localhost'
   ...
Application startup exception: MySql.Data.MySqlClient.MySqlException (0x80004005): Access denied for user 'root'@'localhost'
   at MySqlConnector.Core.ServerSession.ConnectAsync(ConnectionSettings cs, ILoadBalancer loadBalancer, IOBehavior ioBehavior, CancellationToken cancellationToken) in C:\projects\mysqlconnector\src\MySqlConnector\Core\ServerSession.cs:line 356
   at MySql.Data.MySqlClient.MySqlConnection.CreateSessionAsync(Nullable`1 ioBehavior, CancellationToken cancellationToken) in C:\projects\mysqlconnector\src\MySqlConnector\MySql.Data.MySqlClient\MySqlConnection.cs:line 442
   at MySql.Data.MySqlClient.MySqlConnection.OpenAsync(Nullable`1 ioBehavior, CancellationToken cancellationToken) in C:\projects\mysqlconnector\src\MySqlConnector\MySql.Data.MySqlClient\MySqlConnection.cs:line 175
   at MySql.Data.MySqlClient.MySqlConnection.Open() in C:\projects\mysqlconnector\src\MySqlConnector\MySql.Data.MySqlClient\MySqlConnection.cs:line 161
   at Microsoft.EntityFrameworkCore.Storage.RelationalConnection.OpenDbConnection(Boolean errorsExpected)
   at Microsoft.EntityFrameworkCore.Storage.RelationalConnection.Open(Boolean errorsExpected)
   at Pomelo.EntityFrameworkCore.MySql.Storage.Internal.MySqlDatabaseCreator.<>c__DisplayClass18_0.<Exists>b__0(DateTime giveUp)
   at Microsoft.EntityFrameworkCore.ExecutionStrategyExtensions.<>c__DisplayClass12_0`2.<Execute>b__0(DbContext c, TState s)
   at Pomelo.EntityFrameworkCore.MySql.Storage.Internal.MySqlExecutionStrategy.Execute[TState,TResult](TState state, Func`3 operation, Func`3 verifySucceeded)
   at Microsoft.EntityFrameworkCore.ExecutionStrategyExtensions.Execute[TState,TResult](IExecutionStrategy strategy, Func`2 operation, Func`2 verifySucceeded, TState state)
   at Pomelo.EntityFrameworkCore.MySql.Storage.Internal.MySqlDatabaseCreator.Exists(Boolean retryOnNotExists)
   at Microsoft.EntityFrameworkCore.Migrations.HistoryRepository.Exists()
   at Microsoft.EntityFrameworkCore.Migrations.Internal.Migrator.Migrate(String targetMigration)
   at catchme.bg.Startup.Configure(IApplicationBuilder app, IHostingEnvironment env, catchmebgContext db1, CatchmeContext db2) in C:\Users\Ivan\Source\repos\catchme.bg\catchme.bg\catchme.bg\Startup.cs:line 84
--- End of stack trace from previous location where exception was thrown ---
   at Microsoft.AspNetCore.Hosting.ConventionBasedStartup.Configure(IApplicationBuilder app)
   at Microsoft.AspNetCore.Hosting.Internal.WebHost.BuildApplication()
crit: Microsoft.AspNetCore.Hosting.Internal.WebHost[6]
      Application startup exception
MySql.Data.MySqlClient.MySqlException (0x80004005): Access denied for user 'root'@'localhost'
   at MySqlConnector.Core.ServerSession.ConnectAsync(ConnectionSettings cs, ILoadBalancer loadBalancer, IOBehavior ioBehavior, CancellationToken cancellationToken) in C:\projects\mysqlconnector\src\MySqlConnector\Core\ServerSession.cs:line 356
   at MySql.Data.MySqlClient.MySqlConnection.CreateSessionAsync(Nullable`1 ioBehavior, CancellationToken cancellationToken) in C:\projects\mysqlconnector\src\MySqlConnector\MySql.Data.MySqlClient\MySqlConnection.cs:line 442
   at MySql.Data.MySqlClient.MySqlConnection.OpenAsync(Nullable`1 ioBehavior, CancellationToken cancellationToken) in C:\projects\mysqlconnector\src\MySqlConnector\MySql.Data.MySqlClient\MySqlConnection.cs:line 175
   at MySql.Data.MySqlClient.MySqlConnection.Open() in C:\projects\mysqlconnector\src\MySqlConnector\MySql.Data.MySqlClient\MySqlConnection.cs:line 161
   at Microsoft.EntityFrameworkCore.Storage.RelationalConnection.OpenDbConnection(Boolean errorsExpected)
   at Microsoft.EntityFrameworkCore.Storage.RelationalConnection.Open(Boolean errorsExpected)
   at Pomelo.EntityFrameworkCore.MySql.Storage.Internal.MySqlDatabaseCreator.<>c__DisplayClass18_0.<Exists>b__0(DateTime giveUp)
   at Microsoft.EntityFrameworkCore.ExecutionStrategyExtensions.<>c__DisplayClass12_0`2.<Execute>b__0(DbContext c, TState s)
   at Pomelo.EntityFrameworkCore.MySql.Storage.Internal.MySqlExecutionStrategy.Execute[TState,TResult](TState state, Func`3 operation, Func`3 verifySucceeded)
   at Microsoft.EntityFrameworkCore.ExecutionStrategyExtensions.Execute[TState,TResult](IExecutionStrategy strategy, Func`2 operation, Func`2 verifySucceeded, TState state)
   at Pomelo.EntityFrameworkCore.MySql.Storage.Internal.MySqlDatabaseCreator.Exists(Boolean retryOnNotExists)
   at Microsoft.EntityFrameworkCore.Migrations.HistoryRepository.Exists()
   at Microsoft.EntityFrameworkCore.Migrations.Internal.Migrator.Migrate(String targetMigration)
   at catchme.bg.Startup.Configure(IApplicationBuilder app, IHostingEnvironment env, catchmebgContext db1, CatchmeContext db2) in C:\Users\Ivan\Source\repos\catchme.bg\catchme.bg\catchme.bg\Startup.cs:line 84
--- End of stack trace from previous location where exception was thrown ---
   at Microsoft.AspNetCore.Hosting.ConventionBasedStartup.Configure(IApplicationBuilder app)
   at Microsoft.AspNetCore.Hosting.Internal.WebHost.BuildApplication()
Hosting environment: Production
Content root path: /var/MyApp
Now listening on: http://localhost:5000
Application started. Press Ctrl+C to shut down.

我想在应用程序启动时连接到数据库并运行迁移。 但是由于上述错误，它不起作用。

任何想法都会非常有用！

Answer 1

原来，MySql 5.7使用了一个名为'auth_socket'的插件，它使root用户无需密码即可登录mysql。

此行为root帐户设置密码“test”：

ALTER USER 'root'@'localhost' IDENTIFIED WITH mysql_native_password BY 'test';

在appsettings.json和appsettings.production.json文件中设置密码后，一切正常！

这是我用来解决问题的链接：

https://www.percona.com/blog/2016/03/16/change-user-password-in-mysql-5-7-with-plugin-auth_socket/

谢谢大家看我的问题！