Timeout

The timeout behavior cancels handler execution if it exceeds a configured duration, preventing slow operations from blocking indefinitely.

Using the Attribute

[Timeout(5000)] // 5 seconds
public record GenerateReportQuery(DateRange Range) : IQuery<Report>;

Using Configuration

builder.Services.AddTurboMediator(m =>
{
    m.WithTimeout<GenerateReportQuery, Report>(TimeSpan.FromSeconds(5));
});

How It Works

The behavior races the handler execution against a Task.Delay:

Starts the handler and a delay timer in parallel
If the handler completes first → returns the result
If the timer completes first → throws TimeoutException

Practical Example

// Slow external API call with 3-second timeout
[Timeout(3000)]
public record FetchWeatherQuery(string City) : IQuery<WeatherData>;

public class FetchWeatherHandler : IQueryHandler<FetchWeatherQuery, WeatherData>
{
    private readonly HttpClient _httpClient;

    public FetchWeatherHandler(HttpClient httpClient) => _httpClient = httpClient;

    public async ValueTask<WeatherData> Handle(
        FetchWeatherQuery query, CancellationToken ct)
    {
        var response = await _httpClient.GetFromJsonAsync<WeatherData>(
            $"/api/weather/{query.City}", ct);
        return response!;
    }
}

// Usage
try
{
    var weather = await mediator.Send(new FetchWeatherQuery("London"));
}
catch (TimeoutException)
{
    // Handler took too long
    return Results.StatusCode(504);
}

Combining with Retry

Timeout works well with retry — each attempt has its own timeout:

[Retry(maxAttempts: 3, delayMilliseconds: 500)]
[Timeout(2000)]
public record CallApiCommand(string Endpoint) : ICommand<ApiResponse>;