Connect to SQL Server (EF Core)

This page describes how C# consuming apps connect to a SQL Server resource that’s already modeled in your AppHost using Entity Framework Core. For the AppHost API surface — adding a SQL Server instance, databases, and more — see SQL Server Hosting integration.

The Aspire SQL Server EF Core client integration is C#-only. It registers a DbContext subclass through dependency injection and adds health checks and telemetry automatically. Install the 📦 Aspire.Microsoft.EntityFrameworkCore.SqlServer NuGet package in the client-consuming project:

.NET CLI

.NET CLI — Add Aspire.Microsoft.EntityFrameworkCore.SqlServer package

dotnet add package Aspire.Microsoft.EntityFrameworkCore.SqlServer

Program.cs (C# file-based app)

Program.cs

#:package Aspire.Microsoft.EntityFrameworkCore.SqlServer@*

PackageReference (*.csproj)

XML — Add Aspire.Microsoft.EntityFrameworkCore.SqlServer package reference

<PackageReference Include="Aspire.Microsoft.EntityFrameworkCore.SqlServer" Version="*" />

Connection properties

When you reference a SQL Server resource from your AppHost, Aspire injects the connection information into the consuming app as environment variables.

Aspire exposes each property as an environment variable named [RESOURCE]_[PROPERTY]. For instance, the Host property of a resource called sqldb becomes SQLDB_HOST.

SQL Server server resource

The SQL Server server resource exposes the following connection properties:

Property Name	Description
Host	The hostname or IP address of the SQL Server
Port	The port number the SQL Server is listening on
Username	The username for authentication (defaults to sa)
Password	The password for authentication
Uri	The URI of the SQL Server

SQL Server database resource

The SQL Server database resource inherits all properties from its parent SqlServerServerResource and adds:

Property Name	Description
DatabaseName	The name of the database
JdbcConnectionString	The JDBC connection string for the database, with the format jdbc:sqlserver://{Host}:{Port};database={DatabaseName};user={Username};password={Password};encrypt=true;

For example, if you reference a database resource named sqldb in your AppHost project, the following environment variables will be available in the consuming project:

• SQLDB_HOST
• SQLDB_PORT
• SQLDB_URI
• SQLDB_USERNAME
• SQLDB_PASSWORD
• SQLDB_DATABASENAME
• SQLDB_JDBCCONNECTIONSTRING

Connect from your app

Add the Aspire EF Core SQL Server client integration to your C# consuming app to register a DbContext for SQL Server with automatic health checks and telemetry.

C#

Add SQL Server database context

In the Program.cs file of your client-consuming project, call the AddSqlServerDbContext extension method on any IHostApplicationBuilder to register a Microsoft.EntityFrameworkCore.DbContext for use via the dependency injection container. The method takes a connection name parameter.

C# — Program.cs

builder.AddSqlServerDbContext<ExampleDbContext>(connectionName: "database");

Tip

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

To retrieve ExampleDbContext object from a service:

C# — ExampleService.cs

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

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

Enrich a SQL Server database context

You may prefer to use the standard EF Core method to obtain a database context and add it to the dependency injection container:

C# — Program.cs

builder.Services.AddDbContext<ExampleDbContext>(options =>
    options.UseSqlServer(builder.Configuration.GetConnectionString("database")
        ?? throw new InvalidOperationException("Connection string 'database' not found.")));

Note

The connection string name that you pass to the Microsoft.Extensions.Configuration.ConfigurationExtensions.GetConnectionString method must match the name used when adding the SQL server resource in the AppHost project. For more information, see Add SQL Server resource and database resource.

You have more flexibility when you create the database context in this way, for example:

• You can reuse existing configuration code for the database context without rewriting it for Aspire.
• You can use EF Core interceptors to modify database operations.
• You can choose not to use EF Core context pooling, which may perform better in some circumstances.

If you use this method, you can enhance the database context with Aspire-style retries, health checks, logging, and telemetry features by calling the EnrichSqlServerDbContext method:

C# — Program.cs

builder.EnrichSqlServerDbContext<ExampleDbContext>(
    configureSettings: settings =>
    {
        settings.DisableRetry = false;
        settings.CommandTimeout = 30; // seconds
    });

The settings parameter is an instance of the MicrosoftEntityFrameworkCoreSqlServerSettings class.

Configuration

The Aspire SQL Server Entity Framework Core integration provides multiple configuration approaches and options to meet the requirements and conventions of your project.

Use connection string

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

C# — Program.cs

builder.AddSqlServerDbContext<ExampleDbContext>("sql");

The connection string is retrieved from the ConnectionStrings configuration section:

JSON — appsettings.json

{
  "ConnectionStrings": {
    "sql": "Data Source=myserver;Initial Catalog=master"
  }
}

The EnrichSqlServerDbContext 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 ConnectionString.

Use configuration providers

The Aspire SQL Server EF Core integration supports Microsoft.Extensions.Configuration. It loads the MicrosoftEntityFrameworkCoreSqlServerSettings from configuration files such as appsettings.json by using the Aspire:Microsoft:EntityFrameworkCore:SqlServer key. If you have set up your configurations in the Aspire:Microsoft:EntityFrameworkCore:SqlServer section you can just call the method without passing any parameter.

The following is an example of an appsettings.json file that configures some of the available options:

JSON — appsettings.json

{
  "Aspire": {
    "Microsoft": {
      "EntityFrameworkCore": {
        "SqlServer": {
          "ConnectionString": "YOUR_CONNECTIONSTRING",
          "DbContextPooling": true,
          "DisableHealthChecks": true,
          "DisableTracing": true,
          "DisableMetrics": false
        }
      }
    }
  }
}

Use inline configurations

You can also pass the Action<MicrosoftEntityFrameworkCoreSqlServerSettings> delegate to set up some or all the options inline, for example to turn off the metrics:

C# — Program.cs

builder.AddSqlServerDbContext<YourDbContext>(
    "sql",
    static settings =>
        settings.DisableMetrics = true);

Configure multiple DbContext connections

If you want to register more than one DbContext with different configuration, you can use $"Aspire.Microsoft.EntityFrameworkCore.SqlServer:{typeof(TContext).Name}" configuration section name. The json configuration would look like:

JSON — appsettings.json

{
  "Aspire": {
    "Microsoft": {
      "EntityFrameworkCore": {
        "SqlServer": {
          "ConnectionString": "YOUR_CONNECTIONSTRING",
          "DbContextPooling": true,
          "DisableHealthChecks": true,
          "DisableTracing": true,
          "DisableMetrics": false
        },
        "AnotherDbContext": {
          "ConnectionString": "AnotherDbContext_CONNECTIONSTRING",
          "DisableTracing": false
        }
      }
    }
  }
}

Then calling the AddSqlServerDbContext method with AnotherDbContext type parameter would load the settings from Aspire:Microsoft:EntityFrameworkCore:SqlServer:AnotherDbContext section.

C# — Program.cs

builder.AddSqlServerDbContext<AnotherDbContext>("another-sql");

Configuration options

Here are the configurable options with corresponding default values:

Name	Description
ConnectionString	The connection string of the SQL Server database to connect to.
DbContextPooling	A boolean value that indicates whether the db context will be pooled or explicitly created every time it’s requested
MaxRetryCount	The maximum number of retry attempts. Default value is 6, set it to 0 to disable the retry mechanism.
DisableHealthChecks	A boolean value that indicates whether the database health check is disabled or not.
DisableTracing	A boolean value that indicates whether the OpenTelemetry tracing is disabled or not.
DisableMetrics	A boolean value that indicates whether the OpenTelemetry metrics are disabled or not.
Timeout	The time in seconds to wait for the command to execute.

Health checks

By default, the Aspire SQL Server Entity Framework Core integration handles the following:

• Adds the DbContextHealthCheck, which calls EF Core’s CanConnectAsync method. The name of the health check is the name of the TContext type.
• Integrates with the /health HTTP endpoint, which specifies all registered health checks must pass for app to be considered ready to accept traffic.

Observability

Logging

The Aspire SQL Server 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 Aspire SQL Server Entity Framework Core integration will emit the following tracing activities using OpenTelemetry:

• OpenTelemetry.Instrumentation.EntityFrameworkCore

Metrics

The Aspire SQL Server Entity Framework Core integration will emit the following metrics using OpenTelemetry:

• Microsoft.EntityFrameworkCore:
  • ec_Microsoft_EntityFrameworkCore_active_db_contexts
  • ec_Microsoft_EntityFrameworkCore_total_queries
  • ec_Microsoft_EntityFrameworkCore_queries_per_second
  • ec_Microsoft_EntityFrameworkCore_total_save_changes
  • ec_Microsoft_EntityFrameworkCore_save_changes_per_second
  • ec_Microsoft_EntityFrameworkCore_compiled_query_cache_hit_rate
  • ec_Microsoft_Entity_total_execution_strategy_operation_failures
  • ec_Microsoft_E_execution_strategy_operation_failures_per_second
  • ec_Microsoft_EntityFramew_total_optimistic_concurrency_failures
  • ec_Microsoft_EntityF_optimistic_concurrency_failures_per_second