根据服务名调用地址优雅调用服务

package util

import (
    "context"
    "go.etcd.io/etcd/clientv3"
    "io/ioutil"
    "net/http"
    "regexp"
    "time"
)

type Client struct {
    client   *clientv3.Client
    Services []*ServiceInfo
}

type ServiceInfo struct {
    ServiceID   string
    ServiceName string
    ServiceAddr string
}

func NewClient() *Client {
    config := clientv3.Config{
        Endpoints:   []string{"106.12.72.181:23791", "106.12.72.181:23792"},
        DialTimeout: 10 * time.Second,
    }
    client, _ := clientv3.New(config)
    return &Client{client: client}
}

func (this *Client) LoadService() error {
    kv := clientv3.NewKV(this.client)
    res, err := kv.Get(context.TODO(), "/services", clientv3.WithPrefix())
    if err != nil {
        return err
    }
    for _, item := range res.Kvs {
        this.parseService(item.Key, item.Value)
    }
    return nil
}
func (this *Client) parseService(key []byte, value []byte) {
    reg := regexp.MustCompile("/services/(\w+)/(\w+)")
    if reg.Match(key) {
        idandname := reg.FindSubmatch(key)
        sid := idandname[1]
        sname := idandname[2]
        this.Services = append(this.Services, &ServiceInfo{ServiceID: string(sid),
            ServiceName: string(sname), ServiceAddr: string(value)})
    }
}

//定义一个高阶函数返回处理具体url的函数
func (this *Client) GetService(sname string, method string, encodeFunc EncodeRequestFunc) Endpoint {
    for _, service := range this.Services {
        if service.ServiceName == sname {
            return func(ctx context.Context, requestParam interface{}) (responseResult interface{}, err error) {
                httpClient := &http.Client{}
                httpRequest, err := http.NewRequest(method, "http://"+service.ServiceAddr, nil)
                if err != nil {
                    return nil, err
                }
                err = encodeFunc(ctx, httpRequest, requestParam) //这一步是关键，将httpRequest的url修改了
                if err != nil {
                    return nil, err
                }
                res, err := httpClient.Do(httpRequest)
                defer res.Body.Close()
                body, err := ioutil.ReadAll(res.Body)
                if err != nil {
                    return err, nil
                }
                return string(body), nil
            }
        }
    }
    return func(ctx context.Context, requestParam interface{}) (responseResult interface{}, err error) {
        return nil, err
    }
}

各个url处理的函数类型申明

package util

import (
    "context"
    "net/http"
)
//request是调用参数，response是返回结果
type Endpoint func(ctx context.Context,requestParam interface{})(responseResult interface{},err error)

//决定请求path以及参数
type EncodeRequestFunc func(context.Context,*http.Request,interface{}) error

各个url处理的函数类型实现

package serivces

import (
    "context"
    "net/http"
    "strconv"
)

func ProdEncodeFunc(ctx context.Context,httpRequest *http.Request, requestParams interface{}) error {
    prodr:=requestParams.(ProdRequest)
    httpRequest.URL.Path+="/product/"+strconv.Itoa(prodr.ProdId)
    return nil
}

怎么调用这些函数

package main

import (
    "context"
    "fmt"
    "goetcd/services"
    "goetcd/util"
    "log"
)



func main()  {
    client:=util.NewClient()
    err:=client.LoadService()
    if err!=nil{
        log.Fatal(err)
    }
    endpoint:=client.GetService("productservice","GET", serivces.ProdEncodeFunc)
    res,err:= endpoint(context.Background(),serivces.ProdRequest{ProdId:106})
    if err!=nil{
        log.Fatal(err)
    }
    fmt.Println(res)
}

来自为知笔记(Wiz)