In this tutorial, we will explore how to implement health checks and rate limiting in .NET Core applications. Health checks allow you to monitor the status of your application’s dependencies and provide insights into its overall health. Rate limiting helps control and limit the number of requests a client can make within a certain time period. We will use the built-in features of .NET Core to accomplish these tasks.

Prerequisites

Before we begin, make sure you have the following prerequisites:

• .NET Core SDK (version X.X.X or later) installed on your machine.

Step 1: Adding Health Checks

First, let’s add health checks to our .NET Core application. Health checks provide a way to monitor the health of external dependencies, such as databases, third-party services, or any custom components. Open your Startup.cs file and follow these steps:

1. Add the Microsoft.AspNetCore.Diagnostics.HealthChecks package to your project.

2. In the ConfigureServices method, add the following code to register health checks:

services.AddHealthChecks();

3. In the Configure method, add the following code to configure a health check endpoint:

app.UseEndpoints(endpoints =>
{
    endpoints.MapHealthChecks("/health");
});

Save the changes and run your application. You can now access the health check endpoint at http://localhost:5000/health and see the status of your application’s dependencies.

Step 2: Implementing Rate Limiting

Next, let’s implement rate limiting to control the number of requests a client can make within a specified time frame. We will use the AspNetCoreRateLimit NuGet package for this purpose. Follow these steps:

1. Add the AspNetCoreRateLimit package to your project.

2. In the ConfigureServices method, add the following code to configure rate limiting options:

services.AddMemoryCache();
services.Configure<IpRateLimitOptions>(Configuration.GetSection("IpRateLimiting"));
services.Configure<IpRateLimitPolicies>(Configuration.GetSection("IpRateLimitPolicies"));
services.AddInMemoryRateLimiting();

• In the Configure method, add the following code to enable rate limiting middleware:

app.UseIpRateLimiting();

• Open your appsettings.json file and add the following configuration:

"IpRateLimiting": {
  "EnableEndpointRateLimiting": true,
  "EndpointRules": [
    {
      "Endpoint": "*",
      "Limit": 100,
      "Period": "1m"
    }
  ],
  "ClientRules": [
    {
      "ClientId": "*",
      "Limit": 100,
      "Period": "1m"
    }
  ]
}

• Save the changes and run your application. The rate limiting middleware will now restrict the number of requests based on the configured limits.

Conclusion

In this tutorial, we learned how to implement health checks and rate limiting in .NET Core applications. Health checks provide a way to monitor the health of external dependencies, while rate limiting helps control and limit the number of requests. These features are essential for building robust and scalable applications.