First look at .NET Aspire

Announced at the end of 2023 and released in early 2024, by the year 2025 .NET Aspire is now in it's newest release of verison 9.0.0.

But what exactly is .NET Aspire? In the coming weeks, I'm going to explore .NET Aspire and share this journey with you.

I'll create a typical starter task using .NET Aspire from scratch: the classical ToDo List application.

But first, let's see how to get started with Aspire!

What is Aspire?

Aspire is a collection of proven tools, templates, and packages designed to help you build distributed cloud-native applications.

It's important to note that Aspire primarily focuses on the development of cloud-native applications, not their hosting. You will still develop independent Microservices, that you are free to host however and wherever you want.

By nature, Microservices are typically hosted using container orchestration tools like Kubernetes.

To conclude - .NET Aspire is designed to help you with Orchestration and Integrations for your project.

Orchestration

Developing a microservice architecture can be complex, with one of the major challenges being orchestrating multiple services on your development machine.

This is where Aspire can assist you. It's designed to assist with composition - by allowing you to specify the .NET projects, Containers and cloud resources. Besides that, it helps you with service discovery and inter service connectivity.

We will dive a bit deeper into that at the next chapter of this series.

Integrations

Aspire offers a variety of integrations designed to simplify connections to commonly used services. Those integrations are delivered in form of Nuget packages.

To get a glimpse of what's available, type the following in your terminal:

dotnet package search Aspire --take 100

You can find packages Aspire.Confluent.Kafka, Aspire.Azure.Storage.Blobs or Aspire.Hosting.PostgreSQL

Installation

According to the Microsoft Documentation, we need to have .NET 9.0 (or .NET 8.0) and Docker Desktop (or Podman) installed. Since I plan to explore Aspire's latest version, I'll use .NET 9.0 .NET 9.0, and I already have Docker Desktop installed.

To further get started with Aspire, we need to have the .NET Aspire workloads installed. To install them, type the following in a terminal session:

dotnet workload update
dotnet workload install aspire

You can also install Aspire using the Visual Studio Installer. All you have to do is, switch to Individual Components and install the .NET Aspire SDK here.

To create a new Aspire project, switch back to the terminal and type in the following commands:

mkdir ToDoApp && cd ToDoApp
dotnet new aspire

There are quite a few more Aspire project templates. If you are interested, you can type the following in your terminal:

dotnet new list | Select-String aspire

As you can see now, we are going to create an empty Aspire project using our command.

So what do we actually receive here?

Project Structure

Opening the newly created Aspire project in your IDE of choice will present you with two projects

ToDoApp.AppHost
ToDoApp.ServiceDefaults

The AppHost project is the starter project of the solution. It basically manages the orchestration of all services. So whenever you plan to add a new microservice, you have to add the .NET Project using builder.AddProject<T> to register it. You also register integrations like PostgreSQL or Kafka here using extension methods, e.g. builder.AddRedis("cache").

The ServiceDefaults project is used for creating a common base for your microservices. So whenever you create a new service and use the builder.AddServiceDefaults() extension method, the commonly created extensions are added. By default you already have basically the most important stuff to be able to host your service in Kubernetes or any other orchestrator. This includes:

ConfigureOpenTelemetry - makes sure to deliver OpenTelemetry traces and metrices
AddDefaultHealthChecks - adds default liveness check to your app
AddServiceDiscovery - configures and adds service discovery
ConfigureHttpClientDefaults - configures the HTTP client to work with service discovery

As you can see, Asire already handles a lot of concerns you might have when you plan to develop microservices by default.

The Dashboard

Firing up the AppHost project, you will be presented with a nice little dashboard of your service landscape.

Since we currently don't have any service or integration registered, we won't see much here. But we can already get an idea of what we can expect.

We will get an overview of the Resources and we will be able to look into console output, structured logs, traces and metrics of our services.

Conclusion

.NET Aspire appears to be a promising starter set for building distributed services. I'm excited to explore it further in the coming weeks and continue this series of blog posts.

In Part 2, we will be adding a Blazor Frontend, a Web API Project and we will add Entity Framework too.

Stay tuned,
Cheers