Bits of .NET

Network failures happen. Polly adds retry, circuit breaker, and timeout policies automatically.

Install:

dotnet add package Polly
dotnet add package Microsoft.Extensions.Http.Polly

Add to HttpClient:

// Program.cs
builder.Services.AddHttpClient("MyAPI", client =>
{
    client.BaseAddress = new Uri("https://api.example.com");
})
.AddTransientHttpErrorPolicy(policy =>
    policy.WaitAndRetryAsync(3, attempt => TimeSpan.FromSeconds(Math.Pow(2, attempt)))
)
.AddTransientHttpErrorPolicy(policy =>
    policy.CircuitBreakerAsync(5, TimeSpan.FromMinutes(1))
);

Usage:

public class MyService
{
    private readonly IHttpClientFactory _factory;
    
    public MyService(IHttpClientFactory factory)
    {
        _factory = factory;
    }
    
    public async Task GetDataAsync()
    {
        var client = _factory.CreateClient("MyAPI");
        var response = await client.GetAsync("/data");
        // Auto-retries on failure with exponential backoff
        // Circuit breaks after 5 failures in a row
        return await response.Content.ReadFromJsonAsync();
    }
}

Resilient by default!