基于 Golang 的侵入式 Opentracing 实现全链路追踪 ---- 实践篇

docker run -d --name jaeger \
  -e COLLECTOR_ZIPKIN_HTTP_PORT=9411 \
  -p 5775:5775/udp \
  -p 6831:6831/udp \
  -p 6832:6832/udp \
  -p 5778:5778 \
  -p 16686:16686 \
  -p 14268:14268 \
  -p 9411:9411 \
  jaegertracing/all-in-one:1.14

// initJaeger 将jaeger tracer设置为全局tracer
func initJaeger(service string) io.Closer {
	cfg := jaegercfg.Configuration{
		// 将采样频率设置为1，每一个span都记录，方便查看测试结果
		Sampler: &jaegercfg.SamplerConfig{
			Type:  jaeger.SamplerTypeConst,
			Param: 1,
		},
		Reporter: &jaegercfg.ReporterConfig{
			LogSpans: true,
			// 将span发往jaeger-collector的服务地址
			CollectorEndpoint: "http://localhost:14268/api/traces",
		},
	}
	closer, err := cfg.InitGlobalTracer(service, jaegercfg.Logger(jaeger.StdLogger))
	if err != nil {
		panic(fmt.Sprintf("ERROR: cannot init Jaeger: %v\n", err))
	}
	return closer
}

func main() {
	closer := initJaeger("MyProcess")
	defer closer.Close()
	// 获取jaeger tracer
	t := opentracing.GlobalTracer()
	// 创建root span
	sp := t.StartSpan("MyServer")
	// main执行完结束这个span
	defer sp.Finish()
	// 将span传递给MyFirstSpan
	ctx := opentracing.ContextWithSpan(context.Background(), sp)
	MyFirstSpan(ctx)
}

func MyFirstSpan(ctx context.Context) {
	// 开始一个span, 设置span的operation_name=MyFirstSpan
	span, ctx := opentracing.StartSpanFromContext(ctx, "MyFirstSpan")
	defer span.Finish()
	// 将context传递给MySecondSpan
	MySecondSpan(ctx)
	// 假设执行了 http请求
	span.SetTag("http_method", "GET")
	span.SetTag("http_code", "200")
	// 模拟执行耗时
	time.Sleep(1 * time.Second)
}

func MySecondSpan(ctx context.Context) {
	// 开始一个span，设置span的operation_name=MySecondSpan
	span, ctx := opentracing.StartSpanFromContext(ctx, "MySecondSpan")
	defer span.Finish()
	// 模拟执行耗时
	time.Sleep(2 * time.Second)
	// 假设MySecondSpan发生了某些错误
	err := errors.New("something wrong")
	//记录 log
	span.LogFields(
		log.String("event", "error"),
		log.String("message", err.Error()),
		log.Int64("error time ", time.Now().Unix()),
	)
	span.SetTag("error", true)
}