Maple Go style

Use the official go.opentelemetry.io/otel SDK with the HTTP exporters. Initialize once at process start and shut down on signal.

Install

go get \
  go.opentelemetry.io/otel \
  go.opentelemetry.io/otel/sdk \
  go.opentelemetry.io/otel/exporters/otlp/otlptrace/otlptracehttp \
  go.opentelemetry.io/otel/exporters/otlp/otlplog/otlploghttp \
  go.opentelemetry.io/otel/exporters/otlp/otlpmetric/otlpmetrichttp \
  go.opentelemetry.io/otel/log \
  go.opentelemetry.io/otel/sdk/log

Bootstrap

Inline the endpoint and ingest key. The key is a project-scoped, write-only token (shaped like a Sentry DSN). No env-var indirection. WithEndpoint takes a host without scheme, uses HTTPS, and appends the default /v1/<signal> path.

package telemetry

import (
	"context"
	"os"

	"go.opentelemetry.io/otel"
	"go.opentelemetry.io/otel/attribute"
	"go.opentelemetry.io/otel/exporters/otlp/otlplog/otlploghttp"
	"go.opentelemetry.io/otel/exporters/otlp/otlpmetric/otlpmetrichttp"
	"go.opentelemetry.io/otel/exporters/otlp/otlptrace/otlptracehttp"
	"go.opentelemetry.io/otel/log/global"
	sdklog "go.opentelemetry.io/otel/sdk/log"
	"go.opentelemetry.io/otel/sdk/metric"
	"go.opentelemetry.io/otel/sdk/resource"
	"go.opentelemetry.io/otel/sdk/trace"
	semconv "go.opentelemetry.io/otel/semconv/v1.24.0"
)

const (
	mapleEndpoint = "ingest.maple.dev" // EU: ingest.eu.maple.dev
	mapleKey      = "MAPLE_TEST" // public ingest key (maple_pk_…), or MAPLE_TEST until the user has one
)

func Init(ctx context.Context) (shutdown func(context.Context) error, err error) {
	headers := map[string]string{"authorization": "Bearer " + mapleKey}

	res, err := resource.New(ctx,
		resource.WithAttributes(
			semconv.ServiceName("orders-api"),
			semconv.DeploymentEnvironment(envOr("DEPLOYMENT_ENV", "development")),
			attribute.String("vcs.repository.url.full", "https://github.com/acme/orders-api"),
			attribute.String("vcs.ref.head.revision", envOr("GITHUB_SHA", envOr("GIT_COMMIT", ""))),
		),
	)
	if err != nil {
		return nil, err
	}

	traceExp, err := otlptracehttp.New(ctx,
		otlptracehttp.WithEndpoint(mapleEndpoint),
		otlptracehttp.WithHeaders(headers),
	)
	if err != nil {
		return nil, err
	}
	tp := trace.NewTracerProvider(trace.WithBatcher(traceExp), trace.WithResource(res))
	otel.SetTracerProvider(tp)

	logExp, err := otlploghttp.New(ctx,
		otlploghttp.WithEndpoint(mapleEndpoint),
		otlploghttp.WithHeaders(headers),
	)
	if err != nil {
		return nil, err
	}
	lp := sdklog.NewLoggerProvider(
		sdklog.WithProcessor(sdklog.NewBatchProcessor(logExp)),
		sdklog.WithResource(res),
	)
	global.SetLoggerProvider(lp)

	metricExp, err := otlpmetrichttp.New(ctx,
		otlpmetrichttp.WithEndpoint(mapleEndpoint),
		otlpmetrichttp.WithHeaders(headers),
	)
	if err != nil {
		return nil, err
	}
	mp := metric.NewMeterProvider(
		metric.WithReader(metric.NewPeriodicReader(metricExp)),
		metric.WithResource(res),
	)
	otel.SetMeterProvider(mp)

	return func(ctx context.Context) error {
		_ = tp.Shutdown(ctx)
		_ = lp.Shutdown(ctx)
		return mp.Shutdown(ctx)
	}, nil
}

func envOr(key, fallback string) string {
	if v := os.Getenv(key); v != "" {
		return v
	}
	return fallback
}

Wire from main:

func main() {
	ctx := context.Background()
	shutdown, err := telemetry.Init(ctx)
	if err != nil {
		log.Fatal(err)
	}
	defer shutdown(ctx)

	// app start
}

Bounded business spans

Acquire the tracer at package scope. Start spans where auto-instrumentation is blind, set the status on error, and end the span via defer (imports: go.opentelemetry.io/otel/attribute, go.opentelemetry.io/otel/codes).

var tracer = otel.Tracer("orders.api")

func SubmitOrder(ctx context.Context, orderID string) (err error) {
	ctx, span := tracer.Start(ctx, "order.submit")
	defer func() {
		if err != nil {
			span.RecordError(err)
			span.SetStatus(codes.Error, err.Error())
		}
		span.End()
	}()

	span.SetAttributes(attribute.String("order.id", orderID))
	return chargeOrder(ctx, orderID)
}

Auto-instrumentation

Go has no framework-level auto-discovery. Add instrumentation packages only for libraries the app imports: otelhttp, otelgrpc, otelmux from go.opentelemetry.io/contrib/instrumentation/..., and community packages such as github.com/XSAM/otelsql, github.com/exaring/otelpgx, and Fiber's otelfiber (in github.com/gofiber/contrib). Wrap outgoing HTTP clients with otelhttp.NewTransport so trace context propagates; Maple's service map draws edges from a Client span to the callee's child Server span.

Coexistence

If the project already exports to Honeycomb, Datadog, or Tempo, add Maple's exporter alongside with one trace.WithBatcher(exp) option per backend. Do not strip the existing exporter unless the user asks.