WirSchiffenDas

WirSchiffenDas is a proof of concept by Nihad Jabrayilzade. It analyses the optional equipment configuration of a yacht engine, the “Diesel Engine 2000 M96”. Eleven equipment groups are cut into four clusters by physical assembly group (Fluids, Drivetrain, Mechanical and EMS), and each cluster runs as its own NestJS service. Nihad wrote both the code and this documentation; the full repository, runnable with one Docker Compose command, is at github.com/nihadio/wirschiffendas.

The services coordinate themselves by choreography. The coordinator checks the configuration and starts only Fluids; Fluids starts Drivetrain and Mechanical in parallel, and EMS waits until both have reported for the same run. Status and results travel over Kafka and reach the browser as server-sent events. Every REST call between services sits behind a circuit breaker, and a single failed cluster can be retried on its own.

The documentation is compact and dense with tables. Section 6 lists every protected call with its breaker and fallback. Section 9 holds eight decisions, each with the alternatives that were rejected. Section 11 names ten debts and two risks, half of the debts traced to a published catalogue of microservice anti-patterns, and ends with a short retrospective on where orchestration stops and choreography begins.

Nihad explains that design question in an article of his own: Choreography moves the orchestrator’s work, it does not delete it.

This is a snapshot of the documentation as of 25 September 2026. The original covers arc42 sections 1 to 11; section 12 says so. The quality tree at the head of section 10 is Nihad’s own diagram, which his build places in that section. The Markdown source, the PlantUML and Mermaid diagram sources and the OpenAPI documents of the six services are kept in this site’s repository.