golang的OpenTracing和jaeger使用

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OpenTracing是什么？

当代分布式跟踪系统（例如，Zipkin, Dapper, HTrace, X-Trace等）旨在解决这些问题，但是他们使用不兼容的API来实现各自的应用需求。尽管这些分布式追踪系统有着相似的API语法，但各种语言的开发人员依然很难将他们各自的系统（使用不同的语言和技术）和特定的分布式追踪系统进行整合.

OpenTracing通过提供平台无关、厂商无关的API，使得开发人员能够方便的添加（或更换）追踪系统的实现。 OpenTracing提供了用于运营支撑系统的和针对特定平台的辅助程序库。

已经实现OpenTracing协议的项目有：

  • Zipkin
  • Jaeger
  • Appdash

jaeger和OpenTracing

jaeger实现了OpenTracing，而且后端存储支持memry(默认)，elasticsearch,cassandra

jaeger使用

创建一个支持serve模式和client模式的web服务

// main.go
package main
import (
    "flag"
    "log"

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

var (
    serverPort = flag.String("port", "8000", "server port")
    // 默认为服务模式
    actorKind  = flag.String("actor", "server", "server or client")
)

const (
    server = "server"
    client = "client"
)

func main() {
    flag.Parse()

    if *actorKind != server && *actorKind != client {
        log.Fatal("Please specify '-actor server' or '-actor client'")
    }

    cfg := jaegerClientConfig.Configuration{
        Sampler: &jaegerClientConfig.SamplerConfig{
            Type:  "const",
            Param: 1.0, // sample all traces
        },
    }
    // jaeger.NewRemoteReporter(transport)
    tracer, closer, _ := cfg.New(*actorKind)
    defer closer.Close()

    if *actorKind == server {
        runServer(tracer)
        return
    }

    runClient(tracer)

    // Close the tracer to guarantee that all spans that could
    // be still buffered in memory are sent to the tracing backend
    closer.Close()
}

服务器模式

// server.go
package main

import (
    "fmt"
    "io"
    "log"
    "net/http"
    "time"

    "github.com/opentracing-contrib/go-stdlib/nethttp"
    "github.com/opentracing/opentracing-go"
)

func getTime(w http.ResponseWriter, r *http.Request) {
    log.Print("Received getTime request")
    t := time.Now()
    ts := t.Format("Mon Jan _2 15:04:05 2006")
    io.WriteString(w, fmt.Sprintf("The time is %s", ts))
}

func redirect(w http.ResponseWriter, r *http.Request) {
    http.Redirect(w, r,
        fmt.Sprintf("http://localhost:%s/gettime", *serverPort), 301)
}

func runServer(tracer opentracing.Tracer) {
    http.HandleFunc("/gettime", getTime)
    http.HandleFunc("/", redirect)
    log.Printf("Starting server on port %s", *serverPort)
    err := http.ListenAndServe(
        fmt.Sprintf(":%s", *serverPort),
        // use nethttp.Middleware to enable OpenTracing for server
        nethttp.Middleware(tracer, http.DefaultServeMux))
    if err != nil {
        log.Fatalf("Cannot start server: %s", err)
    }
}

客户端模式

// client.go
package main

import (
    "fmt"
    "io/ioutil"
    "log"
    "net/http"

    "github.com/opentracing-contrib/go-stdlib/nethttp"
    "github.com/opentracing/opentracing-go"
    "github.com/opentracing/opentracing-go/ext"
    otlog "github.com/opentracing/opentracing-go/log"
    "golang.org/x/net/context"
)

func runClient(tracer opentracing.Tracer) {
    // nethttp.Transport from go-stdlib will do the tracing
    c := &http.Client{Transport: &nethttp.Transport{}}

    // create a top-level span to represent full work of the client
    span := tracer.StartSpan(client)
    span.SetTag(string(ext.Component), client)
    defer span.Finish()
    ctx := opentracing.ContextWithSpan(context.Background(), span)

    req, err := http.NewRequest(
        "GET",
        fmt.Sprintf("http://localhost:%s/", *serverPort),
        nil,
    )
    if err != nil {
        onError(span, err)
        return
    }

    req = req.WithContext(ctx)
    // wrap the request in nethttp.TraceRequest
    req, ht := nethttp.TraceRequest(tracer, req)
    defer ht.Finish()

    res, err := c.Do(req)
    if err != nil {
        onError(span, err)
        return
    }
    defer res.Body.Close()
    body, err := ioutil.ReadAll(res.Body)
    if err != nil {
        onError(span, err)
        return
    }
    fmt.Printf("Received result: %s\n", string(body))
}

func onError(span opentracing.Span, err error) {
    // handle errors by recording them in the span
    span.SetTag(string(ext.Error), true)
    span.LogKV(otlog.Error(err))
    log.Print(err)
}

编译 go build

执行客户端请求代码 ./opentracing-go-nethttp-demo

运行jaeger的docker镜像 docker run -d -p5775:5775/udp -p16686:16686 jaegertracing/all-in-one:latest

执行客户端代码 ./opentracing-go-nethttp-demo -actor client

此时访问 http://localhost:16686就可以看到jaeger上的记录了。

但是记录好像少了点，只有jaeger-query的，client和server的信息都没记录，查了下资料发现是因为启动jaeger的时候有些端口没开放。

docker run \
-p 5775:5775/udp \
-p 16686:16686 \
-p 6831:6831/udp \
-p 6832:6832/udp \
-p 5778:5778 \
-p 14268:14268 \
jaegertracing/all-in-one:latest

封装http请求

上面的例子就是对http请求的trace

将数据存储在es中

暂时还没成功，后面会更新。这里先把目前的操作记录下来。

在本地用docker启动了elasticsearch

docker run -d -p 9200:9200 -e "http.host=0.0.0.0" -e "transport.host=127.0.0.1" docker.elastic.co/elasticsearch/elasticsearch:5.4.0

在本地用docker-compose启动jaeger

doker-compose.yaml:

jaegertracing:
image: jaegertracing/all-in-one:latest
ports:
    - "5775:5775/udp"
    - "6831:6831/udp"
    - "6832:6832/udp"
    - "5778:5778"
    - "16686:16686"
    - "14268:14268"
command:
    - "/go/bin/standalone-linux"
    - "--span-storage.type=elasticsearch"
    - "--query.static-files=/go/src/jaeger-ui-build/build/"
environment:
  - SPAN_STORAGE_TYPE=elasticsearch

报错： {“level”:”fatal”,”ts”:1528814826.4817529,”caller”:”standalone/main.go:106”,”msg”:”Failed to init storage factory”,”error”:”health check timeout: no Elasticsearch node available”,”errorVerbose”:”no Elasticsearch node available…

解决：

启动es的方式改为：

docker run -it --rm -p 9200:9200 -p 9300:9300 -e "discovery.type=single-node" -e "xpack.security.enabled=false" docker.elastic.co/elasticsearch/elasticsearch:5.4.0

启动jaeger前将宿主主机ip写入到环境变量：

export DOCKERHOST=$(ifconfig | grep -E "([0-9]{1,3}\.){3}[0-9]{1,3}" | grep -v 127.0.0.1 | awk '{ print $2 }' | cut -f2 -d: | head -n1)

修改docker-compose文件

jaegertracing:
image: jaegertracing/all-in-one:latest
ports:
    - "5775:5775/udp"
    - "6831:6831/udp"
    - "6832:6832/udp"
    - "5778:5778"
    - "16686:16686"
    - "14268:14268"
command:
    - "/go/bin/standalone-linux"
    - "--span-storage.type=elasticsearch"
    - "--query.static-files=/go/src/jaeger-ui-build/build/"
environment:
    - SPAN_STORAGE_TYPE=elasticsearch
    - ES_SERVER_URLS=http://$DOCKERHOST:9200

启动jaeger

docker-compose -f jaeger-start-docker.yaml up

大功告成

补充几个es的查询语句

相关链接

jaeger test文档

httptrace和opentracing

jaeger官方文档