11.使用负载均衡的方式调用服务(轮询方式)

Client

package main

import (
    "context"
    "fmt"
    "github.com/go-kit/kit/endpoint"
    "github.com/go-kit/kit/log"
    "github.com/go-kit/kit/sd"
    "github.com/go-kit/kit/sd/consul"
    "github.com/go-kit/kit/sd/lb"
    httptransport "github.com/go-kit/kit/transport/http"
    consulapi "github.com/hashicorp/consul/api"
    "gomicro2/Services"
    "io"
    "net/url"
    "os"
)

func main() {
    //第一步创建client
    {
        config := consulapi.DefaultConfig() //初始化consul的配置
        config.Address = "localhost:8500" //consul的地址
        api_client, _ := consulapi.NewClient(config) //根据consul的配置初始化client
        client := consul.NewClient(api_client) //根据client创建实例

        var logger log.Logger
        {
            logger = log.NewLogfmtLogger(os.Stdout)
            var Tag = []string{"primary"}
            instancer := consul.NewInstancer(client, logger, "userservice", Tag, true) //最后的true表示只有通过健康检查的服务才能被得到
            {
                factory := func(service_url string) (endpoint.Endpoint, io.Closer, error) { //factory定义了如何获得服务端的endpoint,这里的service_url是从consul中读取到的service的address我这里是192.168.3.14:8000
                    tart, _ := url.Parse("http://" + service_url)                                                                                 //server ip +8080真实服务的地址
                    return httptransport.NewClient("GET", tart, Services.GetUserInfo_Request, Services.GetUserInfo_Response).Endpoint(), nil, nil //我再GetUserInfo_Request里面定义了访问哪一个api把url拼接成了http://192.168.3.14:8000/v1/user/{uid}的形式
                }
                endpointer := sd.NewEndpointer(instancer, factory, logger)
                endpoints, _ := endpointer.Endpoints() //获取所有的服务端当前server的所有endpoint函数
                fmt.Println("服务有", len(endpoints), "条")

                mylb := lb.NewRoundRobin(endpointer) //使用go-kit自带的轮询
                for {
                    getUserInfo, err := mylb.Endpoint() //写死获取第一个
                    ctx := context.Background()         //第三步：创建一个context上下文对象

                    //第四步：执行
                    res, err := getUserInfo(ctx, Services.UserRequest{Uid: 101})
                    if err != nil {
                        fmt.Println(err)
                        os.Exit(1)
                    }
                    //第五步：断言，得到响应值
                    userinfo := res.(Services.UserResponse)
                    fmt.Println(userinfo.Result)
                }

            }
        }
    }

}

Server

package main

import (
    "flag"
    "fmt"
    httptransport "github.com/go-kit/kit/transport/http"
    mymux "github.com/gorilla/mux"
    "gomicro/Services"
    "gomicro/utils"
    "log"
    "net/http"
    "os"
    "os/signal"
    "strconv"
    "syscall"
)

func main() {
    name := flag.String("name", "", "服务名称")
    port := flag.Int("port", 0, "服务端口")
    flag.Parse()
    if *name == "" {
        log.Fatal("请指定服务名")
    }
    if *port == 0 {
        log.Fatal("请指定端口")
    }
    utils.SetServiceNameAndPort(*name, *port) //设置服务名和端口

    user := Services.UserService{}
    endp := Services.GenUserEnPoint(user)
    serverHandler := httptransport.NewServer(endp, Services.DecodeUserRequest, Services.EncodeUserResponse) //使用go kit创建server传入我们之前定义的两个解析函数

    r := mymux.NewRouter()
    //r.Handle(`/user/{uid:d+}`, serverHandler) //这种写法支持多种请求方式
    r.Methods("GET", "DELETE").Path(`/user/{uid:d+}`).Handler(serverHandler) //这种写法仅支持Get，限定只能Get请求
    r.Methods("GET").Path("/health").HandlerFunc(func(writer http.ResponseWriter, request *http.Request) {
        writer.Header().Set("Content-type", "application/json")
        writer.Write([]byte(`{"status":"ok"}`))
    })
    errChan := make(chan error)
    go func() {
        utils.RegService()                                                 //调用注册服务程序
        err := http.ListenAndServe(":"+strconv.Itoa(utils.ServicePort), r) //启动http服务
        if err != nil {
            log.Println(err)
            errChan <- err
        }
    }()
    go func() {
        sigChan := make(chan os.Signal)
        signal.Notify(sigChan, syscall.SIGINT, syscall.SIGTERM)
        errChan <- fmt.Errorf("%s", <-sigChan)
    }()
    getErr := <-errChan
    utils.UnRegService()
    log.Println(getErr)
}

来自为知笔记(Wiz)