Add Neon integration for .NET Aspire

[Copilot]

Closes #398

This PR adds support for Neon, a serverless PostgreSQL-compatible database, to the .NET Aspire Community Toolkit.

Overview

Neon is a modern, open-source serverless PostgreSQL-compatible database with managed integration for Azure. While developers can use existing PostgreSQL or Npgsql client integrations, this dedicated integration provides a seamless experience for both local development with Neon containers and production deployment with Neon's cloud service.

What's New

Hosting Integration (CommunityToolkit.Aspire.Hosting.Neon)

Adds hosting support for Neon PostgreSQL containers in .NET Aspire applications:

var builder = DistributedApplication.CreateBuilder(args);

// Add Neon project resource
var neon = builder.AddNeonProject("neon");

// Add databases to the project
var neonDb = neon.AddDatabase("neondb");

// Reference in your services
var api = builder.AddProject<Projects.Api>("api")
    .WithReference(neonDb);

builder.Build().Run();

Features:

• PostgreSQL-compatible container using neondatabase/neon:latest image
• Database resource support with AddDatabase()
• Data persistence with WithDataVolume() and WithDataBindMount()
• Configurable credentials and ports
• Default username "postgres" with auto-generated secure password

Client Integration (CommunityToolkit.Aspire.Neon)

Provides PostgreSQL client support leveraging Aspire.Npgsql:

// In your service Program.cs
builder.AddNeonDataSource("neondb");

// Use via dependency injection
public class MyService
{
    private readonly NpgsqlDataSource _dataSource;
    
    public MyService(NpgsqlDataSource dataSource)
    {
        _dataSource = dataSource;
    }
    
    public async Task<int> GetCountAsync()
    {
        await using var connection = await _dataSource.OpenConnectionAsync();
        await using var command = connection.CreateCommand();
        command.CommandText = "SELECT COUNT(*) FROM users";
        return Convert.ToInt32(await command.ExecuteScalarAsync());
    }
}

Features:

• Configuration support for connection strings, health checks, tracing, and metrics
• Compatible with both local containers and Neon cloud service
• Wraps Aspire.Npgsql for robust PostgreSQL connectivity

Cloud Service Integration

For production scenarios using Neon's cloud service, simply provide your Neon connection string:

{
  "ConnectionStrings": {
    "neondb": "postgresql://user:[email protected]/neondb?sslmode=require"
  }
}

Neon's unique features like database branching are available when using their cloud service and can be managed through their API or CLI alongside this integration.

Additional Resources

• Complete example application demonstrating both hosting and client integrations
• Comprehensive unit tests for resource creation and connection string generation
• API surface area files for public API documentation
• Detailed README files with usage examples and configuration options

Testing

The implementation includes:

• Unit tests for hosting integration (resource creation, connection strings, environment variables)
• Integration test structure for end-to-end validation
• Example application for manual testing and demonstration

---

This integration follows .NET Aspire Community Toolkit conventions and provides a foundation for developers to work with Neon databases in their Aspire applications, whether for local development or cloud deployment.

Warning

Firewall rules blocked me from connecting to one or more addresses (expand for details)

I tried to connect to the following addresses, but was blocked by firewall rules:

• cflvsblobprodcus383.vsblob.vsassets.io
  • Triggering command: dotnet restore (dns block)
• dnceng.pkgs.visualstudio.com
  • Triggering command: dotnet restore (dns block)
  • Triggering command: dotnet build (dns block)
  • Triggering command: dotnet test --no-build --no-restore (dns block)

If you need me to access, download, or install something from one of these locations, you can either:

• Configure Actions setup steps to set up my environment, which run before the firewall is enabled
• Add the appropriate URLs or hosts to the custom allowlist in this repository's Copilot coding agent settings (admins only)

Original prompt

---

This section details on the original issue you should resolve

<issue_title>Add Neon integration</issue_title>
<issue_description>### .NET Aspire issue link

dotnet/aspire#7118

Overview

The Aspire framework does not currently support Neon, a modern, open-source serverless PostgreSQL-compatible database. It has managed integration for Azure as well. While it is possible to use the existing client integrations for PostgreSQL or Npgsql, Neon offers additional features like database branching that are not supported out of the box. We want to enable these unique features through dedicated .NET packages for Aspire.

Usage example

Here is an example of usage

Hosting Integration for Neon

To integrate open source Neon as a hosted resource in a .NET Aspire application:

Install the Aspire.Hosting.Neon NuGet package:

dotnet add package Aspire.Hosting.Neon

Add the Neon server resource in the app host project:

var builder = DistributedApplication.CreateBuilder(args);

// Add Neon server resource with branching support
var neon = builder.AddNeonProject("neon");

// Add a Neon database
var neonDb = neon.AddDatabase("neondb");

// Reference the Neon database in a project
var exampleProject = builder.AddProject<Projects.ExampleProject>()
                            .WithReference(neonDb);

// Initialize and run the application
builder.Build().Run();

Client Integration for Neon

To enable client projects to connect to Neon:

Install the Aspire.Neon NuGet package:

dotnet add package Aspire.Neon

Add the Neon client to the Program.cs file in the client project:

builder.AddNeonDataSource("neondb").addBranch("dev");

Both integrations should align with Aspire's existing conventions and provide a similar experience to the PostgreSQL integration.

Additional context

We are looking for .NET Aspire experts from the community to help us in developing this integration. Let me know your feedback!

Help us help you

Yes, but only if others can assist</issue_description>

Comments on the Issue (you are @copilot in this section)

Fixes #398

---

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[github-actions]

Package	Line Rate	Branch Rate	Complexity	Health
CommunityToolkit.Aspire.EventStore	100%	100%	46	✔
CommunityToolkit.Aspire.GoFeatureFlag	100%	97%	74	✔
CommunityToolkit.Aspire.Hosting.ActiveMQ	79%	40%	100	➖
CommunityToolkit.Aspire.Hosting.ActiveMQ.MassTransit	1%	0%	14	❌
CommunityToolkit.Aspire.Hosting.Adminer	73%	50%	20	➖
CommunityToolkit.Aspire.Hosting.Azure.Dapr	29%	7%	124	❌
CommunityToolkit.Aspire.Hosting.Azure.Dapr.Redis	61%	34%	76	➖
CommunityToolkit.Aspire.Hosting.Azure.DataApiBuilder	100%	100%	22	✔
CommunityToolkit.Aspire.Hosting.Bun	87%	75%	54	✔
CommunityToolkit.Aspire.Hosting.Dapr	67%	55%	834	➖
CommunityToolkit.Aspire.Hosting.DbGate	94%	50%	18	✔
CommunityToolkit.Aspire.Hosting.Deno	84%	75%	72	✔
CommunityToolkit.Aspire.Hosting.EventStore	94%	100%	18	✔
CommunityToolkit.Aspire.Hosting.GoFeatureFlag	93%	50%	18	✔
CommunityToolkit.Aspire.Hosting.Golang	87%	70%	28	✔
CommunityToolkit.Aspire.Hosting.Java	70%	75%	130	➖
CommunityToolkit.Aspire.Hosting.k6	58%	12%	20	❌
CommunityToolkit.Aspire.Hosting.LavinMQ	78%	50%	18	➖
CommunityToolkit.Aspire.Hosting.LavinMQ.MassTransit	1%	0%	14	❌
CommunityToolkit.Aspire.Hosting.MailPit	91%	50%	14	✔
CommunityToolkit.Aspire.Hosting.McpInspector	89%	55%	148	✔
CommunityToolkit.Aspire.Hosting.Meilisearch	73%	57%	50	➖
CommunityToolkit.Aspire.Hosting.Minio	93%	75%	48	✔
CommunityToolkit.Aspire.Hosting.MongoDB.Extensions	96%	83%	36	✔
CommunityToolkit.Aspire.Hosting.MySql.Extensions	100%	88%	78	✔
CommunityToolkit.Aspire.Hosting.Ngrok	52%	35%	82	❌
CommunityToolkit.Aspire.Hosting.NodeJS.Extensions	97%	78%	286	✔
CommunityToolkit.Aspire.Hosting.Ollama	67%	70%	174	➖
CommunityToolkit.Aspire.Hosting.OpenTelemetryCollector	78%	61%	77	➖
CommunityToolkit.Aspire.Hosting.PapercutSmtp	92%	50%	10	✔
CommunityToolkit.Aspire.Hosting.PostgreSQL.Extensions	99%	89%	84	✔
CommunityToolkit.Aspire.Hosting.Python.Extensions	68%	55%	90	➖
CommunityToolkit.Aspire.Hosting.RavenDB	63%	49%	136	➖
CommunityToolkit.Aspire.Hosting.Redis.Extensions	100%	71%	48	✔
CommunityToolkit.Aspire.Hosting.Rust	94%	83%	16	✔
CommunityToolkit.Aspire.Hosting.Solr	96%	100%	14	✔
CommunityToolkit.Aspire.Hosting.SqlDatabaseProjects	76%	63%	154	➖
CommunityToolkit.Aspire.Hosting.Sqlite	99%	89%	42	✔
CommunityToolkit.Aspire.Hosting.SqlServer.Extensions	100%	87%	78	✔
CommunityToolkit.Aspire.Hosting.SurrealDb	54%	37%	234	❌
CommunityToolkit.Aspire.MassTransit.RabbitMQ	100%	100%	30	✔
CommunityToolkit.Aspire.Meilisearch	97%	92%	68	✔
CommunityToolkit.Aspire.Microsoft.Data.Sqlite	89%	85%	52	✔
CommunityToolkit.Aspire.Microsoft.EntityFrameworkCore.Sqlite	61%	58%	114	➖
CommunityToolkit.Aspire.Minio.Client	73%	59%	88	➖
CommunityToolkit.Aspire.OllamaSharp	77%	71%	132	➖
CommunityToolkit.Aspire.RavenDB.Client	60%	53%	237	➖
CommunityToolkit.Aspire.SurrealDb	79%	63%	78	➖
Summary	73% (7314 / 10014)	61% (2182 / 3586)	4398	➖

Minimum allowed line rate is 60%

[aaronpowell]

@Boburmirzo I've had Copilot spin up the starting points for an integration to host Neon Local in Aspire, but as I'm unfamiliar with Neon I'm only guessing that the design would fit.

One concern I have is that, based on my understanding, you need to have a Neon account to run Neon Locally, which I worry would have an impact on our ability to provide a good set of tests, so I want to confirm that that is the case.