Building a .NET API Gateway with ClickHouse and Aspire

Summary

The tutorial builds a .NET distributed application around a YARP API gateway, two backend APIs, an analytics API, a Blazor dashboard, a load generator, and ClickHouse. Aspire’s AppHost coordinates these resources, injects connection strings and service endpoints, orders startup with dependency health checks, and exposes selected services through stable or external endpoints. The gateway records proxied requests in ClickHouse while emitting OpenTelemetry metrics for request counts, duration, and backend failures. A bounded queue and background ingestion keep request logging off the hot path, while a narrow schema and materialized view precompute minute-level aggregates for volume, p95 latency, error rates, and route comparisons. Aspire supplies live telemetry, whereas ClickHouse retains request history for analytical queries and drill-down into slow requests.

Takeaways

1. 1

   Aspire can manage ClickHouse as a first-class application resource, inject its connection string, provide health checks and tracing, and coordinate service startup without hard-coded peer URLs.

2. 2

   A bounded queue with background ingestion keeps gateway request logging off the hot path while retaining request history in ClickHouse.

3. 3

   A materialized view precomputes minute-level aggregate states, allowing dashboard queries to merge summaries instead of scanning the full request_logs table on every refresh.