Golang微服务：Micro Trace使用opentracing jaeger

trace

Micro通过Wrapper实现了三种trace接口，aswxray,opencensus,opentracing,这里主要关注opentracing，opentracing已成为行业标准。

opentracing

要引入OpenTracing方案，只需要opentracing.NewClientWrapper加入Client或者Server即可。

func NewClientWrapper(ot opentracing.Tracer) client.Wrapper {
    return func(c client.Client) client.Client {
        return &otWrapper{ot,c}
    }
}

opentracing.NewClientWrapper方法入参是实现OpenTracing的接口opentracing.Tracer

type Tracer interface {
    StartSpan(operationName string,opts ...StartSpanOption) Span
    Inject(sm SpanContext,format interface{},carrier interface{}) error
    Extract(format interface{},carrier interface{}) (SpanContext,error)
}

jaeger

部署一个测试的jaeger,服务器地址:192.168.8.144，Agent的默认端口是5775。

/home/service/base/jaeger
[[email?protected] jaeger]# ll
total 158444
-rwxr-xr-x 1 root root 14565068 Nov 16 19:35 example-hotrod
-rwxr-xr-x 1 root root 20387089 Nov 16 19:35 jaeger-agent
-rwxr-xr-x 1 root root 38456594 Nov 16 19:35 jaeger-all-in-one
-rwxr-xr-x 1 root root 29731462 Nov 16 19:35 jaeger-collector
-rwxr-xr-x 1 root root 25523281 Nov 16 19:35 jaeger-ingester
-rwxr-xr-x 1 root root 33563911 Nov 16 19:35 jaeger-query
-rwxr-xr-x 1 root root       43 Nov 16 19:36 run
-rw-r--r-- 1 root root     1939 Nov 16 19:36 x.log
[[email?protected] jaeger]# cat run
nohup ./jaeger-all-in-one  >> x.log 2>&1 &

jaeger是一款分布式的追踪系统，实现了opentracingAPI标准，也是Go生态的，是CNCF成员。

func TestJaeger(t *testing.T) {
    cfg := config.Configuration{
        ServiceName: "MicroTestService",//自定义服务名称
        Sampler: &config.SamplerConfig{
            Type:  "const",Param: 1,},Reporter: &config.ReporterConfig{
            LogSpans:            true,BufferFlushInterval: 1 * time.Second,LocalAgentHostPort:  "192.168.8.144:5775",//jaeger agent
        },}
    tracer,closer,err := cfg.NewTracer()
    if err != nil {
        t.Error(err)
        return
    }
    defer closer.Close()

    r := mock.NewRegistry()
    s := selector.NewSelector(selector.Registry(r))

    c := client.NewClient(
        // set the selector
        client.Selector(s),// add the trace wrapper
        client.Wrap(NewClientWrapper(tracer)),)

    req := c.NewRequest("test.service","Test.Method",map[string]string{
        "foo": "bar",client.WithContentType("application/json"))

    var rsp map[string]interface{}
    c.Call(context.TODO(),req,rsp)
    t.Log(rsp)
}

浏览器访问:http://192.168.8.144:16686/search可以发现有服务MicroTestService的访问追踪了