.NET Aspire: Setting Up Your Environment

If you are new to .NET Aspire, I would suggest reading my last article on .NET Aspire with the following link: How to Get Started with .NET Aspire

Now, Before getting started with .NET Aspire, ensure you have the following prerequisites installed in your system.

1. .NET SDK (Latest Version)

Download and install the latest .NET SDK from the official .NET download page.
Verify installation by running.
dotnet --version

2. IDE (Integrated Development Environment)

.NET Aspire works best with,

Visual Studio 2022 (v17.8 or later): Recommended for Windows users.
Visual Studio Code with C# extension: Lightweight alternative for cross-platform development.

3. Additional Tools

Docker (optional but recommended for containerized deployments)
Postman or REST client (for testing APIs)

Installing .NET Aspire

To install .NET Aspire, follow these steps.

For Visual Studio Users.

Open Visual Studio Installer.
Select Modify on your existing installation.
Under Workloads, ensure ASP.NET and Web Development are selected.
Click Modify to install/update the required components.

For .NET CLI Users

Run the following command to install the Aspire templates.

dotnet new install Aspire.ProjectTemplates

Let’s see in action.

Templates

Here as you can see, once you install the Aspire templates it shows you a success message with the list of the templates.

You may check this list of templates if you have already installed the Aspire on your system by verifying the installation using the following command on the dot.net CLI.

dotnet new aspire --list

Creating Your First .NET Aspire Project

Now, let's create a simple Aspire application. There are two ways to start working with .NET aspire projects, Using CLI or IDE like Visual Studio or VS code (with extensions).

1. Using .NET CLI

Run the following command to create a new Aspire project.

dotnet new aspire -n MyAspireAppByCLI

Let’s see in Action.

New Aspire project

Navigate into the project directory and run.

dotnet run –project MyAspireAppBuCLI.AppHost

Project Directory

It will build the project and will run on a local port number, you can click on the link as well as to check.

Port number

Using Visual Studio 2022

Open Visual Studio and select Create a New Project.
Search for the Aspire Application template and select it.
Name your project and click Create.
Once we click on next it’ll ask for the .NET core version you want for this project and other details, select as per the requirement and click next/create.
.NET Aspire solution, named AspireAppByVS2022, consists of four projects, each serving a specific role in the microservices-based architecture. These projects help structure cloud-native applications efficiently.

1. AspireAppByVS2022.ApiService (API Service)

Purpose
- This is a backend service (API) that exposes endpoints to be consumed by other applications.
- It handles business logic and data processing.
Key Files
- Program.cs: The entry point of the API, where the web application and services are configured.
- appsettings.json: Stores configuration settings like connection strings, logging levels, etc.
How Does It Work?
- Typically, this project will have controllers (e.g., WeatherController.cs) that define API endpoints.
- Other services (e.g., the Web UI) can call this API service for fetching/storing data.

2. AspireAppByVS2022.AppHost (Application Host)

Purpose
- This is the main orchestration project responsible for running all Aspire services together.
- It acts as the entry point for launching the application and managing service dependencies.
Key Files
- Program.cs: Configures and starts all microservices.
- appsettings.json: Stores configuration settings.
How Does It Work?
- When you run the application (dotnet runs inside this project), it automatically starts all the services like Web, API, and dependencies.
- It simplifies service discovery and makes deployment easier.

3. AspireAppByVS2022.ServiceDefaults

Purpose
- This project provides default configurations and reusable service settings for the entire Aspire application.
- It is a shared library that other projects (API, Web, AppHost) can use.
Key Files
- Extensions.cs: Contains helper methods and extensions for configuring services.
How Does It Work?
- Instead of writing the same configurations in every project, common settings (e.g., logging, security policies) are centralized here.
- The API and Web projects reference this to maintain consistency.

4. AspireAppByVS2022.Web (Web UI)

Purpose
- This is the front-end web application (possibly an ASP.NET Core Blazor or MVC project).
- It interacts with AspireAppByVS2022.ApiService to fetch and display data.
Key Files
- Program.cs: Configures the web application and registers dependencies.
- appsettings.json: Stores configurations specific to the web UI.
- WeatherApiClient.cs: A client for calling the API service.
- wwwroot/: Contains static files (CSS, JavaScript, images).
How Does It Work?
- It serves as the user interface (UI) for the application.
- It fetches data from the API (AspireAppByVS2022.ApiService) and presents it to users.

How These Projects Work Together?

AppHost starts and manages the lifecycle of all services.
API Service handles business logic and serves data.
Web UI communicates with the API to display data.
ServiceDefaults provides shared configurations.

How to Run the Application?

Since AppHost is the main entry point, you can run the entire Aspire application using the command on the dotnet CLI or simply press F5 as we are in Visual Studio 2022 IDE and it understands it well.

dotnet run --project AspireAppByVS2022.AppHost

This will start the API service.

Start the Web UI
Load necessary configurations from ServiceDefaults
Ensure smooth service orchestration

In the next article, we’ll dive into the Core Concepts of .NET Aspire and understand how Aspire simplifies microservices development.