playground/Lambda/Lambda.ServiceDefaults/Extensions.cs

using Microsoft.AspNetCore.Builder;
using Microsoft.AspNetCore.Diagnostics.HealthChecks;
using Microsoft.Extensions.DependencyInjection;
using Microsoft.Extensions.Diagnostics.HealthChecks;
using Microsoft.Extensions.Logging;
using Microsoft.Extensions.ServiceDiscovery;
using OpenTelemetry;
using OpenTelemetry.Instrumentation.AWSLambda;
using OpenTelemetry.Metrics;
using OpenTelemetry.Trace;

namespace Microsoft.Extensions.Hosting
{
    // Adds common .NET Aspire services: service discovery, resilience, health checks, and OpenTelemetry.
    // This project should be referenced by each service project in your solution.
    // To learn more about using this project, see https://aka.ms/dotnet/aspire/service-defaults
    public static class Extensions
    {
        public static TBuilder AddServiceDefaults<TBuilder>(this TBuilder builder) where TBuilder : IHostApplicationBuilder
        {
            builder.ConfigureOpenTelemetry();

            builder.AddDefaultHealthChecks();

            builder.Services.AddServiceDiscovery();

            builder.Services.ConfigureHttpClientDefaults(http =>
            {
                // Turn on resilience by default
                http.AddStandardResilienceHandler();

                // Turn on service discovery by default
                http.AddServiceDiscovery();
            });

            // Uncomment the following to restrict the allowed schemes for service discovery.
            // builder.Services.Configure<ServiceDiscoveryOptions>(options =>
            // {
            //     options.AllowedSchemes = ["https"];
            // });

            return builder;
        }

        public static TBuilder ConfigureOpenTelemetry<TBuilder>(this TBuilder builder) where TBuilder : IHostApplicationBuilder
        {
            builder.Logging.AddOpenTelemetry(logging =>
            {
                logging.IncludeFormattedMessage = true;
                logging.IncludeScopes = true;
            });

            builder.Services.AddOpenTelemetry()
                .WithMetrics(metrics =>
                {
                    metrics.AddAspNetCoreInstrumentation()
                        .AddHttpClientInstrumentation()
                        .AddAWSInstrumentation()
                        .AddRuntimeInstrumentation();
                })
                .WithTracing(tracing =>
                {
                    tracing.AddSource(builder.Environment.ApplicationName)
                        .AddAspNetCoreInstrumentation()
                        .AddAWSInstrumentation()
                        .AddAWSLambdaConfigurations(options => options.DisableAwsXRayContextExtraction = true)
                        .AddHttpClientInstrumentation();
                });

            builder.AddOpenTelemetryExporters();

            return builder;
        }

        private static TBuilder AddOpenTelemetryExporters<TBuilder>(this TBuilder builder) where TBuilder : IHostApplicationBuilder
        {
            var useOtlpExporter = !string.IsNullOrWhiteSpace(builder.Configuration["OTEL_EXPORTER_OTLP_ENDPOINT"]);

            if (useOtlpExporter)
            {
                builder.Services.AddOpenTelemetry().UseOtlpExporter();
            }

            return builder;
        }

        public static TBuilder AddDefaultHealthChecks<TBuilder>(this TBuilder builder) where TBuilder : IHostApplicationBuilder
        {
            builder.Services.AddHealthChecks()
                // Add a default liveness check to ensure app is responsive
                .AddCheck("self", () => HealthCheckResult.Healthy(), ["live"]);

            return builder;
        }

        public static WebApplication MapDefaultEndpoints(this WebApplication app)
        {
            // Adding health checks endpoints to applications in non-development environments has security implications.
            // See https://aka.ms/dotnet/aspire/healthchecks for details before enabling these endpoints in non-development environments.
            if (app.Environment.IsDevelopment())
            {
                // All health checks must pass for app to be considered ready to accept traffic after starting
                app.MapHealthChecks("/health");

                // Only health checks tagged with the "live" tag must pass for app to be considered alive
                app.MapHealthChecks("/alive", new HealthCheckOptions
                {
                    Predicate = r => r.Tags.Contains("live")
                });
            }

            return app;
        }
    }
}