Send OpenTelemetry from Go to your Mac

Go has no automatic instrumentation. You start the SDK yourself, in about twenty lines, and wrap the handlers you care about.

Before you start

• Loggerhead is open.
• You know the effective port. Open Collectors → Loggerhead receiver → Connection and copy the HTTP port. The first workspace uses 4318. See Ports and the effective port.

Step 1: get the packages

go get go.opentelemetry.io/otel \
  go.opentelemetry.io/otel/sdk \
  go.opentelemetry.io/otel/exporters/otlp/otlptrace/otlptracehttp \
  go.opentelemetry.io/contrib/instrumentation/net/http/otelhttp

Step 2: start the tracer provider

main.go

func startTracing(ctx context.Context) (func(context.Context) error, error) {
  exporter, err := otlptracehttp.New(ctx)
  if err != nil {
    return nil, err
  }
  res, err := resource.New(ctx,
    resource.WithAttributes(semconv.ServiceName("my-go-service")),
  )
  if err != nil {
    return nil, err
  }
  tp := trace.NewTracerProvider(
    trace.WithBatcher(exporter),
    trace.WithResource(res),
  )
  otel.SetTracerProvider(tp)
  return tp.Shutdown, nil
}

otlptracehttp.New reads OTEL_EXPORTER_OTLP_ENDPOINT, so the address stays out of the code.

Step 3: wrap the handler

mux := http.NewServeMux()
mux.Handle("/orders", ordersHandler)
http.ListenAndServe(":8080", otelhttp.NewHandler(mux, "http"))

Step 4: set the endpoint

export OTEL_EXPORTER_OTLP_ENDPOINT=http://127.0.0.1:4318

Run the service and call one route.

What arrives

Signal	State
Traces	Every handler you wrap, and every client call you instrument.
Metrics	Add the metric SDK and otlpmetrichttp the same way.
Logs	Add otelslog to bridge log/slog, or send the output through a branch collector.

Tag the environment

export OTEL_RESOURCE_ATTRIBUTES=deployment.environment.name=staging

See Workspaces and environments.

Then read it with your agent

1. Open Traces in Loggerhead and click a request to open its waterfall.
2. Connect your coding agent once, and it reads the same data. See Claude Code.