mysql-entity-framework-integration.md

title	.NET Aspire Pomelo MySQL Entity Framework Core integration
description	Learn how to use the .NET Aspire MySQL Entity Framework integration, which includes both hosting and client integrations.
ms.date	12/09/2024

.NET Aspire Pomelo MySQL Entity Framework Core integration

[!INCLUDE includes-hosting-and-client]

MySQL is an open-source Relational Database Management System (RDBMS) that uses Structured Query Language (SQL) to manage and manipulate data. It's employed in a many different environments, from small projects to large-scale enterprise systems and it's a popular choice to host data that underpins microservices in a cloud-native application. The .NET Aspire Pomelo MySQL Entity Framework Core integration enables you to connect to existing MySQL databases or create new instances from .NET with the mysql container image.

Hosting integration

[!INCLUDE mysql-app-host]

Client integration

To get started with the .NET Aspire Pomelo MySQL Entity Framework integration, install the 📦 Aspire.Pomelo.EntityFrameworkCore.MySql NuGet package in the client-consuming project, that is, the project for the application that uses the MySQL Entity Framework Core client.

.NET CLI

dotnet add package Aspire.Pomelo.EntityFrameworkCore.MySql

PackageReference

<PackageReference Include="Aspire.Pomelo.EntityFrameworkCore.MySql"
                  Version="*" />

---

For more information, see dotnet add package or Manage package dependencies in .NET applications.

Add a MySQL database context

In the :::no-loc text="Program.cs"::: file of your client-consuming project, call the xref:Microsoft.Extensions.Hosting.AspireEFMySqlExtensions.AddMySqlDbContext%2A extension method on any xref:Microsoft.Extensions.Hosting.IHostApplicationBuilder to register a xref:Microsoft.EntityFrameworkCore.DbContext for use through the dependency injection container. The method takes a connection name parameter.

builder.AddMySqlDbContext<ExampleDbContext>(connectionName: "mysqldb");

Tip

The connectionName parameter must match the name used when adding the SQL Server database resource in the app host project. In other words, when you call AddDatabase and provide a name of mysqldb that same name should be used when calling AddMySqlDbContext. For more information, see Add MySQL server resource and database resource.

To retrieve ExampleDbContext object from a service:

public class ExampleService(ExampleDbContext context)
{
    // Use context...
}

For more information on dependency injection, see .NET dependency injection.

Add a MySQL database context with enrichment

To enrich the DbContext with additional services, such as automatic retries, health checks, logging and telemetry, call the xref:Microsoft.Extensions.Hosting.AspireEFMySqlExtensions.EnrichMySqlDbContext* method:

builder.EnrichMySqlDbContext<ExampleDbContext>(
    connectionName: "mysqldb",
    configureSettings: settings =>
    {
        settings.DisableRetry = false;
        settings.CommandTimeout = 30 // seconds
    });

The settings parameter is an instance of the xref:Aspire.Pomelo.EntityFrameworkCore.MySql.PomeloEntityFrameworkCoreMySqlSettings class.

Configuration

The .NET Aspire Pomelo MySQL Entity Framework Core integration provides multiple options to configure the database connection based on the requirements and conventions of your project.

Use a connection string

When using a connection string from the ConnectionStrings configuration section, you can provide the name of the connection string when calling builder.AddMySqlDatabaseDbContext<TContext>():

builder.AddMySqlDatabaseDbContext<MyDbContext>("mysql");

And then the connection string will be retrieved from the ConnectionStrings configuration section:

{
  "ConnectionStrings": {
    "mysql": "Server=mysql;Database=mysqldb"
  }
}

The EnrichMySqlDbContext won't make use of the ConnectionStrings configuration section since it expects a DbContext to be registered at the point it's called.

For more information, see the MySqlConnector: ConnectionString documentation.

Use configuration providers

The .NET Aspire Pomelo MySQL Entity Framework Core integration supports xref:Microsoft.Extensions.Configuration?displayProperty=fullName. It loads the xref:Aspire.Pomelo.EntityFrameworkCore.MySql.PomeloEntityFrameworkCoreMySqlSettings from configuration files such as :::no-loc text="appsettings.json"::: by using the Aspire:Pomelo:EntityFrameworkCore:MySql key.

The following example shows an :::no-loc text="appsettings.json"::: that configures some of the available options:

{
  "Aspire": {
    "Pomelo": {
      "EntityFrameworkCore": {
        "MySql": {
          "ConnectionString": "YOUR_CONNECTIONSTRING",
          "DisableHealthChecks": true,
          "DisableTracing": true
        }
      }
    }
  }
}

For the complete MySQL integration JSON schema, see Aspire.Pomelo.EntityFrameworkCore.MySql/ConfigurationSchema.json.

Use inline delegates

You can also pass the Action<PomeloEntityFrameworkCoreMySqlSettings> delegate to set up some or all the options inline, for example to disable health checks from code:

builder.AddMySqlDbContext<MyDbContext>(
    "mysqldb",
    static settings => settings.DisableHealthChecks = true);

or

builder.EnrichMySqlDbContext<MyDbContext>(
    static settings => settings.DisableHealthChecks = true);

[!INCLUDE client-integration-health-checks]

The .NET Aspire Pomelo MySQL Entity Framework Core integration:

• Adds the health check when xref:Aspire.Pomelo.EntityFrameworkCore.MySql.PomeloEntityFrameworkCoreMySqlSettings.DisableHealthChecks?displayProperty=nameWithType is false, which calls EF Core's xref:Microsoft.EntityFrameworkCore.Storage.IDatabaseCreator.CanConnectAsync%2A method.
• Integrates with the /health HTTP endpoint, which specifies all registered health checks must pass for app to be considered ready to accept traffic.

[!INCLUDE integration-observability-and-telemetry]

Logging

The .NET Aspire Pomelo MySQL Entity Framework Core integration uses the following log categories:

• Microsoft.EntityFrameworkCore.ChangeTracking
• Microsoft.EntityFrameworkCore.Database.Command
• Microsoft.EntityFrameworkCore.Database.Connection
• Microsoft.EntityFrameworkCore.Database.Transaction
• Microsoft.EntityFrameworkCore.Infrastructure
• Microsoft.EntityFrameworkCore.Migrations
• Microsoft.EntityFrameworkCore.Model
• Microsoft.EntityFrameworkCore.Model.Validation
• Microsoft.EntityFrameworkCore.Query
• Microsoft.EntityFrameworkCore.Update

Tracing

The .NET Aspire Pomelo MySQL Entity Framework Core integration will emit the following tracing activities using OpenTelemetry:

• MySqlConnector

Metrics

The .NET Aspire Pomelo MySQL Entity Framework Core integration currently supports the following metrics:

• MySqlConnector:
  • db.client.connections.create_time
  • db.client.connections.use_time
  • db.client.connections.wait_time
  • db.client.connections.idle.max
  • db.client.connections.idle.min
  • db.client.connections.max
  • db.client.connections.pending_requests
  • db.client.connections.timeouts
  • db.client.connections.usage

See also

• MySQL database
• Entity Framework Core docs
• .NET Aspire integrations
• .NET Aspire GitHub repo