handler.go

package main

import (
	"log"
	"net/http"
	"net/http/httptest"

	"go.opentelemetry.io/otel/api/global"
	"go.opentelemetry.io/otel/api/kv"
	tracestdout "go.opentelemetry.io/otel/exporters/trace/stdout"
	"go.opentelemetry.io/otel/instrumentation/othttp"
	"go.opentelemetry.io/otel/sdk/resource"
	sdktrace "go.opentelemetry.io/otel/sdk/trace"
)

func initTracer() {
	var err error
	exp, err := tracestdout.NewExporter(tracestdout.Options{PrettyPrint: false})
	if err != nil {
		log.Panicf("failed to initialize trace stdout exporter %v", err)
		return
	}
	tp, err := sdktrace.NewProvider(sdktrace.WithSyncer(exp),
		sdktrace.WithConfig(sdktrace.Config{DefaultSampler: sdktrace.AlwaysSample()}),
		sdktrace.WithResource(resource.New(kv.String("rk1", "rv11"), kv.Int64("rk2", 5))))
	if err != nil {
		log.Panicf("failed to initialize trace provider %v", err)
	}
	global.SetTraceProvider(tp)
}

func main() {
	initTracer()

	var handler http.Handler
	handler = http.HandlerFunc(noop)
	handler = othttp.NewHandler(handler, "")

	w := httptest.NewRecorder()
	req := httptest.NewRequest("GET", "/", nil)

	handler.ServeHTTP(w, req)

	select {}
}

func noop(w http.ResponseWriter, req *http.Request) {}