LevelUp.ServiceDefaults 0.5.0

LevelUp.ServiceDefaults

The lean, AOT-safe paved-road core for lvlup-sw services. One call wires OpenTelemetry (logging, metrics, tracing with ASP.NET Core, HttpClient, and runtime instrumentation), default health checks, service discovery, and the standard HttpClient resilience handler, with validated options bound from the LevelUp:ServiceDefaults configuration section.

Heavy dependencies (Sentry, Azure Monitor, Microsoft.Identity.Web) live in the satellite packages — LevelUp.ServiceDefaults.Sentry, .Azure, and .Auth — so this core stays trim/AOT-clean.

Usage

var builder = WebApplication.CreateBuilder(args);

builder.AddLevelUpServiceDefaults();

var app = builder.Build();
app.MapDefaultEndpoints(); // /health and /alive (absent in Production by default)
app.Run();

The OTLP exporter is registered only when an endpoint is configured (via OtlpEndpoint or the OTEL_EXPORTER_OTLP_ENDPOINT environment variable). The team and tier resource attributes resolve from options → configuration → environment (LVLUP_TEAM/LVLUP_TIER); when neither is set they fall back to "unknown" and a single warning is logged at startup naming which fell back.

Optional health hardening (opt-in, default off)

Three capabilities lifted from the Ares aegis host are available as opt-in options; they are off by default, so existing consumers are unaffected.

• EnableReadinessEndpoint maps a /health/ready probe reporting only the checks tagged ReadinessTag (default "ready") — the host's hard dependencies. Register hard dependencies (migrations, FHIR, …) with that tag and soft dependencies (cache) without it, so a cache outage cannot fail readiness and evict the pod (incident #341).
• ExcludeProbePathsFromTracing drops /health, /health/ready, and /alive from ASP.NET Core traces, removing in-cluster probe noise/cost.
• EnableHealthResponseCaching applies a request-timeout (HealthCheckTimeout, default 5s) and an output-cache (HealthResponseCacheDuration, default 10s) policy to the health endpoints.

Correlation id (default on)

AddLevelUpServiceDefaults puts a correlation middleware at the head of the request pipeline. You do not call anything to get it. It runs before authentication, authorization, and endpoint routing.

For each request the middleware does this:

• It adopts the inbound X-Correlation-ID header when the value is well formed.
• It mints a new lower-case UUID when the header is absent or malformed. A malformed value is discarded. It is never propagated and never written to the log.
• It writes the resolved value back to the request header and to HttpContext.Items["LevelUp.CorrelationId"].
• It puts the value on Activity.Current as the tag and baggage key levelup.correlation_id. W3C trace-context continues to flow. The tag lets a trace and an audit record join on one key.
• It writes the value to the response header, and it opens a log scope with the property CorrelationId.

A value is well formed when it has 1 to 128 characters from the set [A-Za-z0-9._:-]. The rule is strict because the value comes from the caller and it lands in an audit record and in Log Analytics.

Options bind from LevelUp:ServiceDefaults:Correlation. A bad value stops the start and names the property.

Do not change HeaderName. The BFF and the health packages use the same literal. A different name breaks the chain.

On a worker or another non-web host the registration is inert.