The Pipeline Framework

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Client Step Extensions ​

Client steps are generated classes used by the orchestrator to call backend services. You can extend them when you need custom behaviour.

Typical Extensions ​

  1. Add metrics around remote calls
  2. Wrap calls with retries or fallbacks
  3. Enrich headers or metadata before invoking the client step (gRPC, REST, or Local)

Client step types ​

  • GrpcClientStep: use when the runtime boundary is remote and you want the stricter protobuf contract and generated stubs.
  • RestClientStep: use when the runtime boundary is remote and HTTP/JSON interoperability matters more than protobuf transport efficiency.
  • LocalClientStep: use when the step runs in-process and you want the same orchestration shape without a network hop.

Extend a generated client step ​

Subclass the generated step when you need custom headers, metrics, or policy around the generated invocation.

java
@ApplicationScoped
public class InstrumentedParseDocumentClientStep extends ParseDocumentGrpcClientStep {
    @Inject
    MeterRegistry registry;

    @Override
    public Uni<ParsedDocument> invoke(ParsedDocumentRequest request) {
        Timer.Sample sample = Timer.start(registry);
        return super.invoke(request)
            .invoke(() -> sample.stop(registry.timer("tpf.client.parse-document")))
            .onFailure().invoke(error -> registry.counter("tpf.client.parse-document.failures").increment());
    }
}

Common customisations ​

  • Add metrics around remote calls.
  • Wrap calls with retries or fallbacks.
  • Enrich headers or metadata before invoking the client step (GrpcClientStep, RestClientStep, or LocalClientStep).