Telemetry

This repository contains utilities for working with Open Telemetry. You can find a getting started guide with OpenTelemetry in Go on opentelemetry.io

Usage

Initialize the telemetry providers within main()

cfg := &telemetry.Config{
    ServiceName:        os.Getenv("OTEL_SERVICE_NAME"),
    OtelEndpoint:       os.Getenv("OTEL_EXPORTER_OTLP_ENDPOINT"),
}

cleanup, err := telemetry.InitProviders(ctx, cfg)
if err != nil {
    // handle error
}

Example Lambda Setup

func main() {
    ctx, cancel := signal.NotifyContext(context.Background(), os.Interrupt)
    defer cancel()

    logger := slog.New(slog.NewJSONHandler(os.Stdout, nil))
    slog.SetDefault(logger)

    cfg := &telemetry.Config{
        ServiceName:        os.Getenv("OTEL_SERVICE_NAME"),
        OtelEndpoint:       os.Getenv("OTEL_EXPORTER_OTLP_ENDPOINT"),
        Lambda:             true,
    }

    cleanup, err := telemetry.InitProviders(ctx, cfg)
    if err != nil {
        // handle error
    }

    adapter := primary.NewLambdaAdapter()

    // any remaining setup for lambda...

    lambda.StartWithOptions(
        otellambda.InstrumentHandler(adapter.HandleRequest,
            otellambda.WithTracerProvider(otel.GetTracerProvider()),
            otellambda.WithFlusher(otel.GetTracerProvider().(*trace.TracerProvider)),
            otellambda.WithPropagator(otel.GetTextMapPropagator()),
        ),
        lambda.WithContext(ctx),
        lambda.WithEnableSIGTERM(func() {
            cleanup()
            cancel()
        }),
    )
}

Instrumentation

Applications can be manually instrumented or you can use any of the officially supported instrumentation libraries

docs: https://opentelemetry.io/docs/languages/go/instrumentation/#metrics

To add custom spans within your application, the following can be done

ctx, span := tracer.Start(ctx, "Adapter.HandleRequest")
defer span.End()

docs: https://opentelemetry.io/docs/languages/go/instrumentation/#creating-spans

AWS SDK

Add the following after initialization to instrument the aws sdk

// init aws config
cfg, err := awsConfig.LoadDefaultConfig(ctx)
if err != nil {
    // handle error
}

// instrument all aws clients
otelaws.AppendMiddlewares(&cfg.APIOptions)

Host and Runtime Metrics

Add the following after initialization to instrument host and runtime metric collection

err = host.Start(host.WithMeterProvider(otel.GetMeterProvider()))
if err != nil {
    // handle error
}

err = runtime.Start(runtime.WithMeterProvider(otel.GetMeterProvider()), runtime.WithMinimumReadMemStatsInterval(time.Second))
if err != nil {
    // handle error
}