Taking .NET Aspire for a spin

.NET Aspire is an interesting piece of the.NET ecosystem, providing a framework for building, testing, and deploying cloud-native applications. Still relatively new, Aspire takes an opinionated approach to distributed systems development while also providing easy-to-use connectors that let you quickly add key services to your applications..NET Aspire supports local development, helping you compose the elements that make up an application, with a simple way to manage the various authorization tokens and connection strings for services. It lets you quickly add containers to your application and helps manage them. It mixes familiar C# code with declarative JSON to handle integrations.

The aim is to support building and running distributed code, with a focus on your development process by giving you a high-level abstraction of the underlying platform. You don’t need to know about the niceties of building and managing containers, or discovering and configuring services, as much of that is managed by Aspire’s own integrations.

At the heart of.NET Aspire is its dashboard, which gives you many of the necessary observability and management tools for your code. You can launch and debug applications, and at the same time watch their performance and behavior along with external resources running in containers.

The latest release is.NET Aspire 9.3, which targets the current long-term and short-term releases of the.NET platform,.NET 8.0 and.NET 9.0. Among the improvements, the update brings GitHub Copilot debugging to Aspire dashboard.

Setting up.NET Aspire

I put together a basic test system to try out the.NET Aspire release. There aren’t many prerequisites; much of what’s needed is part of the standard.NET install. The value comes from its collection of NuGet packages that simplify connections to popular services, with a set of templates to manage application development.

As Aspire is designed to build cloud-native applications, the first thing you need is a container runtime on your development system. I’ve used Docker in the past, but this time I decided to install the open source Podman, using Windows Subsystem for Linux (WSL) as the virtualization provider for its containers.

Podman’s Windows setup is straightforward. Start by downloading Podman Desktop and then, once installed, follow its guide to get your container host up and running. As this was my first, I simply accepted the defaults. This set everything up for me, including adding kubectl support. Podman creates its own WSL instance, which you can access from the Windows Terminal, much like any other WSL Linux distribution.

With a container host in place, you can set up your choice of IDE. Aspire has support for Visual Studio, Visual Studio Code (with the C# developer kit installed), or JetBrains Rider. Rider users will need to install its Aspire plug-in. If you prefer another editor, the.NET CLI will help you build the scaffolding for an Aspire application.

If you’re using Visual Studio and want to use Aspire 9.3, have the command line install the latest version from the.NET CLI, as the bundled templates in the Visual Studio Installer are still from Version 8. Installing the new versions will overwrite the older release. Installing the Visual Studio Code tool automatically ensures you have the latest version.

Building your first.NET Aspire project

Once you’ve installed Aspire’s tool in your chosen IDE, you can quickly create a starter app project with one of the standard templates. Alongside its basic.NET features, the starter template will install and configure a Redis instance in your container host, downloading and starting a Redis container for an application cache. You don’t need to do any configuration; Aspire will manage this all for you.

Launching the starter application first installs a localhost HTTPS certificate for your test code. You will need to restart all your running browser windows to ensure that the new certificate is trusted. It then loads the Aspire dashboard so you can launch the starter app’s front end.

The dashboard is the heart of.NET Aspire. This is a web-based tool that shows you quickly what’s happening in your application. Having one place to view the components of a distributed application is useful, as you can quickly drill down into each part to see its health and metrics associated with key features.

The dashboard adds a lot to the traditional debugging tools in Visual Studio. While Visual Studio manages your code, the Aspire dashboard uses OpenTelemetry running in your code to get details of how the various components of your application are working—including any service containers installed from public or private repositories. So, if your code takes a dependency of Redis and installs a Redis container from Docker Hub, the dashboard can monitor how it’s being used and if any issues need to be addressed.

The main resource view shows the components of your application: those you’ve written and the services they’re using. You can view it as a table or as a graph that shows how the components are connected. The console view shows messages from each service, which can be viewed in more detail as structured logs. Other views let you drill down into individual traces and into the various metrics associated with an application, including.NET’s Kestrel web server and YARP reverse proxy.

Using the.NET Aspire dashboard with GitHub Copilot

One of the latest features of the Aspire dashboard is support for GitHub Copilot, using it as a conversational tool for providing basic analysis of your application. Like all generative AI tools, it’s important to check its results, but initial impressions are good. That’s likely because it’s grounded by first the.NET and C# elements of the Copilot model, and then by the logs and source code of your application.

It’s probably best to treat the dashboard Copilot as an overly enthusiastic intern: It will do what you ask, and because it’s grounded in your logs and other data, the results will be accurate. However, it’s not creative like a pair programmer would be, so it won’t contribute or spot issues proactively.

It’s still helpful, especially when you’re starting out with.NET Aspire. Adding Copilot to the dashboard gives you a useful tool for surfacing information about a running application that may be hard to view with other tools. As useful as that is, you need to remember that this tool will do exactly what you ask, so be careful to ask the right questions and double-check its answers.

You do need to be logged into a GitHub account in either Visual Studio or Visual Studio Code to use the new Copilot tool. Once you’re logged in and launch your code, you’ll see the Copilot icon in the top right corner of the dashboard. Click this to open a chat window, which is persistent within the context of your current dashboard session unless you specifically request a new chat. You can ask your own questions or use the preset prompts, which provide shortcuts to common scenarios.

Buttons in the Copilot chat let you expand the view, making it easier to look at responses. Much of the output is in list format, and the expanded view allows you to see most list elements on a single line. Along with detailed answers, Copilot will deliver a quick summary that gives you an overview of its response.

The Copilot button gives you a whole application view, and other views in the dashboard have their own access to it. So, for example, if you’re looking at traces, there’s the option to have Copilot analyze the data associated with a specific trace, drilling down further into the metrics linked to a trace so you can quickly see client latency as well as any additional logs.

Simplifying cloud-native development.NET Aspire is becoming a key tool for building and testing cloud-native applications using.NET. Its support for foundational building blocks, like containers, and managing authentication, authorization, and connections simplifies much of the necessary platform work, letting you quickly stand up a development environment on a Windows PC (with Windows Subsystem for Linux).

The resulting focus on developer productivity and tools is key to understanding.NET Aspire and how its dashboard shows you how the different components of a distributed application interact, helping you understand where to focus time and effort. Its rapid development is welcome, with each new release adding important features and services. As.NET continues to evolve, Aspire is evolving with it, ensuring that Microsoft’s development platform and tools remain relevant in the modern enterprise cloud.