Minimal example for using Jaeger Tracing with Go

docker-compose.yml

version: "3"
services: 
  jaeger:
    image: jaegertracing/all-in-one:1.8
    ports: 
      - 6831:6831/udp
      - 6832:6832/udp
      - 5778:5778
      - 16686:16686
      - 14268:14268

go.mod

module tracing-example

go 1.12

require (
	github.com/opentracing/opentracing-go v1.1.0
	github.com/pkg/errors v0.8.1 // indirect
	github.com/uber/jaeger-client-go v2.21.1+incompatible
	github.com/uber/jaeger-lib v2.2.0+incompatible // indirect
	go.uber.org/atomic v1.5.1 // indirect
)

main.go

package main

import (
	"context"
	"fmt"
	"time"

	"github.com/opentracing/opentracing-go"
	"github.com/uber/jaeger-client-go/config"
)

func main() {
	cfg, err := config.FromEnv()
	if err != nil {
		panic(err)
	}

	cfg.ServiceName = "tracing-example"

	tracer, closer, err := cfg.NewTracer()
	if err != nil {
		panic(err)
	}
  
  defer closer.Close()

	opentracing.SetGlobalTracer(tracer)

  example()
}

func example() {
	span := opentracing.StartSpan("some-operation")
	span.SetTag("key", "some-value")
  
  defer span.Finish()

	ctx := opentracing.ContextWithSpan(context.Background(), span)

	executeLongRunningOperation(ctx)
	executeLongRunningOperation(ctx)
}

func executeLongRunningOperation(ctx context.Context) {
	span, _ := opentracing.StartSpanFromContext(ctx, "long-running-operation")
	defer span.Finish()

	// "subCtx" kann nun WIEDER an weitere Funktionen weitergereicht werden,
	// um Spans noch tiefer zu verschachteln

	time.Sleep(5 * time.Second)
	fmt.Println("done")
}