Building Your First Microservice with .NET

This tutorial guides you through the fundamental steps of creating a simple microservice using .NET and ASP.NET Core. We'll focus on core concepts and best practices to get you started quickly.

Step 1: Project Setup

Start by creating a new ASP.NET Core Web API project. Open your terminal or command prompt and navigate to your desired project directory.


dotnet new webapi -n MyFirstMicroservice
cd MyFirstMicroservice

This command creates a new project named MyFirstMicroservice with the necessary configuration for a Web API.

Step 2: Define Your Service's Responsibility

A microservice should have a single, well-defined responsibility. For this example, let's create a simple service that manages a list of products.

Create a new folder named Models in your project root. Inside Models, create a file named Product.cs:


namespace MyFirstMicroservice.Models
{
    public class Product
    {
        public int Id { get; set; }
        public string Name { get; set; }
        public decimal Price { get; set; }
    }
}

Step 3: Create a Controller

Controllers handle incoming HTTP requests. Create a new folder named Controllers. Inside Controllers, create a file named ProductsController.cs:


using Microsoft.AspNetCore.Mvc;
using MyFirstMicroservice.Models;
using System.Collections.Generic;
using System.Linq;

namespace MyFirstMicroservice.Controllers
{
    [ApiController]
    [Route("api/[controller]")]
    public class ProductsController : ControllerBase
    {
        private static List<Product> _products = new List<Product>
        {
            new Product { Id = 1, Name = "Laptop", Price = 1200.00m },
            new Product { Id = 2, Name = "Keyboard", Price = 75.50m },
            new Product { Id = 3, Name = "Mouse", Price = 25.00m }
        };

        [HttpGet]
        public ActionResult<IEnumerable<Product>> GetAllProducts()
        {
            return Ok(_products);
        }

        [HttpGet("{id}")]
        public ActionResult<Product> GetProductById(int id)
        {
            var product = _products.FirstOrDefault(p => p.Id == id);
            if (product == null)
            {
                return NotFound();
            }
            return Ok(product);
        }

        [HttpPost]
        public ActionResult<Product> CreateProduct([FromBody] Product newProduct)
        {
            if (newProduct == null)
            {
                return BadRequest();
            }
            newProduct.Id = _products.Count > 0 ? _products.Max(p => p.Id) + 1 : 1;
            _products.Add(newProduct);
            return CreatedAtAction(nameof(GetProductById), new { id = newProduct.Id }, newProduct);
        }
    }
}

This controller exposes endpoints for getting all products, getting a product by ID, and creating a new product. We're using a static list for simplicity; in a real application, you would use a database.

Step 4: Run Your Microservice

You can now run your microservice from the terminal:


dotnet run

Your service will typically start on http://localhost:5000 or https://localhost:5001. You can test the endpoints using tools like Postman or by navigating to them in your browser.

To test the POST endpoint, you'll need to use a tool like Postman and send a POST request to https://localhost:5001/api/products with a JSON body representing a new product.

Next Steps

Congratulations on building your first microservice! From here, you can explore:

View on GitHub