Observability and local orchestration

Local development

The Aspire AppHost orchestrates PostgreSQL, the API, React/Vite, OpenTelemetry Collector, Prometheus, Loki, Tempo, and Grafana:

dotnet run --project src/Horizon.AppHost

AppHost is a development and test orchestrator. Production runs separate API and web containers behind a same-origin reverse proxy.

Telemetry flow

• Serilog is the structured ILogger provider and emits JSON console logs.
• The OpenTelemetry SDK instruments HTTP, runtime, Npgsql, and outbox activity.
• The Collector batches, retries, and routes signals.
• Loki stores logs, Tempo stores traces, and Prometheus scrapes metrics.
• Grafana provisions data sources and starter dashboards from source control.

Trykatch does not run Jaeger beside Tempo. Jaeger is documented only as an alternative trace backend.

Health endpoints

• /health/live proves the process is alive.
• /health/ready proves required runtime dependencies are ready.

Production ingress must protect operational endpoints according to the deployment environment.