ResQ.BuildingBlocks.ServiceDefaults 0.2.0

ResQ.BuildingBlocks.ServiceDefaults

Aspire-style cross-cutting defaults — one call from a host's composition root wires observability, health, resilience, and a testable clock. Depends only on ResQ.BuildingBlocks.Application + ResQ.BuildingBlocks.Domain.

What AddServiceDefaults wires

• OpenTelemetry (ConfigureOpenTelemetry): logs (IncludeScopes + IncludeFormattedMessage), metrics (ASP.NET Core + HTTP-client + runtime instrumentation + the ResqDiagnostics.MeterName meter), and traces (ASP.NET Core + HTTP-client sources + the ResqDiagnostics.ActivitySourceName source). The OTLP exporter turns on only when OTEL_EXPORTER_OTLP_ENDPOINT is set.
• Health checks (AddDefaultHealthChecks): a self liveness check tagged live.
• Service discovery + standard HTTP resilience: applied to every HttpClient via ConfigureHttpClientDefaults.
• IClock → singleton SystemClock (backed by TimeProvider.System).

It does not register the observability pipeline behaviors — that is an explicit, ordered call (below).

var builder = WebApplication.CreateBuilder(args);
builder.AddServiceDefaults();               // OTel / health / resilience / IClock — NO behaviors

builder.Services
    .AddResqApplication(typeof(CreateWidget).Assembly)
    .AddValidatorsFrom(typeof(CreateWidget).Assembly)
    .AddLoggingPipeline()                    // outermost
    .AddValidationPipeline();
builder.Services.AddResqObservabilityBehaviors();   // Tracing then Metrics — AFTER validation

var app = builder.Build();
app.MapDefaultEndpoints();                   // /health + /alive (non-Production)
app.Run();

Resulting behavior order: Logging → Validation → Tracing → Metrics → Transaction → handler (first-registered = outermost).

Pieces

• ServiceDefaultsExtensions — AddServiceDefaults, ConfigureOpenTelemetry, AddDefaultHealthChecks (IHostApplicationBuilder), and MapDefaultEndpoints (WebApplication).
• ResqDiagnostics — the shared ActivitySource + the ActivitySourceName/MeterName constants. No hand-newed static Meter; metrics come from IMeterFactory so the emitting and allow-listed names always match.
• TracingBehavior<,> / MetricsBehavior<,> — CQRS pipeline behaviors. Tracing starts an activity named for the request and sets ok/error status (tags no business data); metrics record a duration histogram + failure counter, tagged by request name. AddResqObservabilityBehaviors registers both.
• AddResqOptions<T>(sectionName) — bind a config section, ValidateDataAnnotations, and ValidateOnStart (fail fast at boot).
• AddResqResiliencePipeline(key, configure?) — a Polly retry + circuit-breaker + timeout pipeline whose retry ShouldHandle treats a failed Result with ErrorType.Failure (or any exception) as retryable.

Known coupling (accepted)

FrameworkReference Microsoft.AspNetCore.App and AddAspNetCoreInstrumentation are unconditional, so a pure worker host that calls AddServiceDefaults still pulls the ASP.NET shared framework. This mirrors Aspire's own ServiceDefaults; a ServiceDefaults.Worker split is possible future work.

Apache-2.0 · part of resq-software/dotnet.