# AspirePostgreSqlNpgsqlExtensions Methods

- Package: [Aspire.Npgsql](/reference/api/csharp/aspire.npgsql.md)
- Type: [AspirePostgreSqlNpgsqlExtensions](/reference/api/csharp/aspire.npgsql/aspirepostgresqlnpgsqlextensions.md)
- Kind: `Methods`
- Members: `2`

Extension methods for connecting PostgreSQL database with Npgsql client

## AddKeyedNpgsqlDataSource(IHostApplicationBuilder, string, Action<NpgsqlSettings>, Action<NpgsqlDataSourceBuilder>)

- Name: `AddKeyedNpgsqlDataSource(IHostApplicationBuilder, string, Action<NpgsqlSettings>, Action<NpgsqlDataSourceBuilder>)`
- Modifiers: `extension`
- Source: [GitHub](https://github.com/microsoft/aspire/blob/cbc352350f1a9bafbaff10d14a2c8de4ac186a48/src/Components/Aspire.Npgsql/AspirePostgreSqlNpgsqlExtensions.cs#L49-L52)

Registers `NpgsqlDataSource` as a keyed service for given `name` for connecting PostgreSQL database with Npgsql client. Configures health check, logging and telemetry for the Npgsql client.

```csharp
public static class AspirePostgreSqlNpgsqlExtensions
{
    public static void AddKeyedNpgsqlDataSource(
        this IHostApplicationBuilder builder,
        string name,
        Action<NpgsqlSettings>? configureSettings = null,
        Action<NpgsqlDataSourceBuilder>? configureDataSourceBuilder = null)
    {
        // ...
    }
}
```

## Parameters

- `builder` (`IHostApplicationBuilder`)
  The `Hosting.IHostApplicationBuilder` to read config from and add services to.
- `name` (`string`)
  The name of the component, which is used as the `ServiceDescriptor.ServiceKey` of the service and also to retrieve the connection string from the ConnectionStrings configuration section.
- `configureSettings` (`Action<NpgsqlSettings>`) `optional`
  An optional method that can be used for customizing options. It's invoked after the settings are read from the configuration.
- `configureDataSourceBuilder` (`Action<NpgsqlDataSourceBuilder>`) `optional`
  An optional delegate that can be used for customizing the `NpgsqlDataSourceBuilder`.

## Exceptions

- `ArgumentNullException` -- Thrown when `builder` or `name` is null.
- `ArgumentException` -- Thrown if mandatory `name` is empty.
- `InvalidOperationException` -- Thrown when mandatory [NpgsqlSettings.ConnectionString](/reference/api/csharp/aspire.npgsql/npgsqlsettings/properties.md#connectionstring) is not provided.

## Remarks

Reads the configuration from "Aspire:Npgsql:{name}" section.

## AddNpgsqlDataSource(IHostApplicationBuilder, string, Action<NpgsqlSettings>, Action<NpgsqlDataSourceBuilder>)

- Name: `AddNpgsqlDataSource(IHostApplicationBuilder, string, Action<NpgsqlSettings>, Action<NpgsqlDataSourceBuilder>)`
- Modifiers: `extension`
- Source: [GitHub](https://github.com/microsoft/aspire/blob/cbc352350f1a9bafbaff10d14a2c8de4ac186a48/src/Components/Aspire.Npgsql/AspirePostgreSqlNpgsqlExtensions.cs#L33)

Registers `NpgsqlDataSource` service for connecting PostgreSQL database with Npgsql client. Configures health check, logging and telemetry for the Npgsql client.

```csharp
public static class AspirePostgreSqlNpgsqlExtensions
{
    public static void AddNpgsqlDataSource(
        this IHostApplicationBuilder builder,
        string connectionName,
        Action<NpgsqlSettings>? configureSettings = null,
        Action<NpgsqlDataSourceBuilder>? configureDataSourceBuilder = null)
    {
        // ...
    }
}
```

## Parameters

- `builder` (`IHostApplicationBuilder`)
  The `Hosting.IHostApplicationBuilder` to read config from and add services to.
- `connectionName` (`string`)
  A name used to retrieve the connection string from the ConnectionStrings configuration section.
- `configureSettings` (`Action<NpgsqlSettings>`) `optional`
  An optional delegate that can be used for customizing options. It's invoked after the settings are read from the configuration.
- `configureDataSourceBuilder` (`Action<NpgsqlDataSourceBuilder>`) `optional`
  An optional delegate that can be used for customizing the `NpgsqlDataSourceBuilder`.

## Exceptions

- `ArgumentNullException` -- Thrown if mandatory `builder` is null.
- `InvalidOperationException` -- Thrown when mandatory [NpgsqlSettings.ConnectionString](/reference/api/csharp/aspire.npgsql/npgsqlsettings/properties.md#connectionstring) is not provided.

## Remarks

Reads the configuration from "Aspire:Npgsql" section.