Performance test your ASP.NET Core application using NBomber

Yesterday I talked about Bombardier, an HTTP benchmarking tool written in Go and how you can use it to test the performance of your ASP.NET Core applications. While discussing the usage, a colleague mentioned another load testing tool, NBomber.

NBomber is a load-testing framework for Pull and Push scenarios, designed to test any system regardless of a protocol (HTTP/WebSockets/AMQP, etc) or a semantic model (Pull/Push).

It goes a lot further than what Bombardier has to offer. One of the things I find nice is that load test scenario’s can be written using C#. 😉

Remark: NBomber comes with a free personal license, if you want to use it inside your organization, you’ll have to buy a business license.

Let’s write a simple load test to test our API!

• We start by creating a new Console application and adding the NBomber nuget package:
• dotnet add package NBomber
• As we want to test an HTTP endpoint, let’s also add the NBomber.Http plugin to simplify defining and handling of HTTP load tests:
• dotnet add package NBomber.Http
• Now we can start writing our test scenario. Here is a simple example scenario where we call our API endpoint simulating 100 users:

 

	using NBomber.CSharp;
	using NBomber.Http.CSharp;
	using var httpClient = new HttpClient();
	var scenario = Scenario.Create("call_http_api_scenario", async context =>
	{
	var request =
	Http.CreateRequest("GET", "http://localhost:5042/WeatherForecast")
	.WithHeader("Accept", "application/json");
	var response = await Http.Send(httpClient, request);
	return response;
	})
	.WithWarmUpDuration(TimeSpan.FromSeconds(2))
	.WithLoadSimulations(
	Simulation.Inject(rate: 100,
	interval: TimeSpan.FromSeconds(1),
	during: TimeSpan.FromSeconds(30))
	);
	NBomberRunner
	.RegisterScenarios(scenario)
	.Run();

view raw Program.cs hosted with ❤ by GitHub

• To run the scenario, we only have to run the console app:

• After test completion results, results are written in multiple formats to a folder.
  

• Here is how the HTML report looks like after the test run;

 

Want to learn more? Check out this video introduction: