accounting.md

title	linkTitle	aliases	cSpell:ignore
Accounting Service	Accounting	accountingservice	otelsarama otlptracegrpc sarama sdktrace

This service calculates the total amount of sold products. This is only mocked and received orders are printed out.

Accounting Service

Traces

Initializing Tracing

The OpenTelemetry SDK is initialized from main using the initTracerProvider function.

func initTracerProvider() (*sdktrace.TracerProvider, error) {
    ctx := context.Background()

    exporter, err := otlptracegrpc.New(ctx)
    if err != nil {
        return nil, err
    }
    tp := sdktrace.NewTracerProvider(
        sdktrace.WithBatcher(exporter),
        sdktrace.WithResource(initResource()),
    )
    otel.SetTracerProvider(tp)
    otel.SetTextMapPropagator(propagation.NewCompositeTextMapPropagator(propagation.TraceContext{}, propagation.Baggage{}))
    return tp, nil
}

You should call TracerProvider.Shutdown() when your service is shutdown to ensure all spans are exported. This service makes that call as part of a deferred function in main

tp, err := initTracerProvider()
if err != nil {
    log.Fatal(err)
}
defer func() {
    if err := tp.Shutdown(context.Background()); err != nil {
        log.Printf("Error shutting down tracer provider: %v", err)
    }
}()

Adding Kafka ( Sarama ) auto-instrumentation

This service will receive the processed results of the Checkout Service via a Kafka topic. To instrument the Kafka client the ConsumerHandler implemented by the developer has to be wrapped.

handler := groupHandler{} // implements sarama.ConsumerGroupHandler
wrappedHandler := otelsarama.WrapConsumerGroupHandler(&handler)