利用go-kit组件进行服务注册与发现和健康检查的操作

在go的微服务架构中

使用go-kit组件进行开发微服务

type Reg struct {
	Host string
	Port int
	Client consul.Client
}
func MakeReg (host string , port int) (*Reg , error) {
	reg := api.DefaultConfig()
	reg.Address = host + ":" + strconv.Itoa(port)
	apiclient , err = api.NewClient(reg)
	if err != nil {
		return nil , err
	}
	client := consul.NewClient(apiclient)
	return &Reg{Host : host , Port : port ,Client : client} , nil
}
func (r Reg) Resiter (servicename , tag , host , seviceid ,checkinter ,healthcheckhttp ,deregisterafter string , port int) bool {
	congig := api.AgentServiceRegistration{
		Port : port ,
		Address : host ,
		Name := servicename,
		ID := serviceid,
		Ckeck : &api.AgentServiceCheck{
			Interval : checkinter,
			HTTP : "http://" + host + ":" + healthcheckhttp ,
			DeregisterCriticalServiceAfter : deregisterafter,
		}
	}
	if err := r.Client.Register(&config) ; err != nil {
		fmt.Println(err)
		return false
	}
	return true
}
func (r Reg) Deregister (serviceid string) bool {
	dreg := api.AgentServiceRegistration{ID : serviceid}
	if err != r.Client.Deregister(&config) ; err != nil {
		fmt.Println(err)
		return false
	}
	return true
}
func (r Reg) discover (servicename , tag string ,passingonly bool) ( []*api.ServiceEntry ,error ) {
	if entries ,_ ,err := r.Client.Service(servicename , tag , passingonly , nil) ;err != nil {
		return nil ,err
	}else{
		return entries , nil
	}
}

补充：go-kit 与 grpc 结合实现注册发现与负载均衡

介绍

grpc提供了简单的负载均衡，需要自己实现服务发现resolve。我们既然要使用go-kit来治理微服务，那么我们就使用go-kit的注册发现、负载均衡机制。

go-kit官方【stringsvc3】例子中使用的负载均衡方案是通过服务端转发进行，翻找下源码go-kit的服务注册发现、负载均衡在【sd】包中。下面我们介绍怎么通过go-kit进行客户端负载均衡。

go-kit提供的注册中心

1、 etcd

2、 consul

3、 eureka

4、 zookeeper

go-kit提供的负载均衡

1、 random[随机]

2、 roundRobin[轮询]

只需实现Balancer接口，我们可以很容易的增加其它负载均衡机制

type Balancer interface {
   Endpoint() (endpoint.Endpoint, error)
}

etcd注册发现

etcd和zookeeper类似是一个高可用、强一致性的存储仓库，拥有服务发现功能。 我们就通过go-kit提供的etcd包来实现服务注册发现

服务端代码

服务注册

1、连接注册中心

2、注册当前服务

var (
   //etcd服务地址
   etcdServer = "127.0.0.1:2379"
   //服务的信息目录
   prefix     = "/services/book/"
   //当前启动服务实例的地址
   instance   = "127.0.0.1:50052"
   //服务实例注册的路径
   key        = prefix + instance
   //服务实例注册的val
   value      = instance
   ctx        = context.Background()
   //服务监听地址
   serviceAddress = ":50052"
)
//etcd的连接参数
options := etcdv3.ClientOptions{
   DialTimeout: time.Second * 3,
   DialKeepAlive: time.Second * 3,
}
//创建etcd连接
client, err := etcdv3.NewClient(ctx, []string{etcdServer}, options)
if err != nil {
   panic(err)
}
// 创建注册器
registrar := etcdv3.NewRegistrar(client, etcdv3.Service{
   Key:   key,
   Value: value,
}, log.NewNopLogger())
// 注册器启动注册
registrar.Register()

完整代码

package main
import (
   "grpc-test/pb"
   "context"
   grpc_transport "github.com/go-kit/kit/transport/grpc"
   "github.com/go-kit/kit/endpoint"
   "google.golang.org/grpc"
   "net"
   "github.com/go-kit/kit/sd/etcdv3"
   "github.com/go-kit/kit/log"
   "time"
)
type BookServer struct {
   bookListHandler  grpc_transport.Handler
   bookInfoHandler  grpc_transport.Handler
}
//通过grpc调用GetBookInfo时,GetBookInfo只做数据透传, 调用BookServer中对应Handler.ServeGRPC转交给go-kit处理
func (s *BookServer) GetBookInfo(ctx context.Context, in *book.BookInfoParams) (*book.BookInfo, error) {
   _, rsp, err := s.bookInfoHandler.ServeGRPC(ctx, in)
   if err != nil {
      return nil, err
   }
   return rsp.(*book.BookInfo),err
}
//通过grpc调用GetBookList时,GetBookList只做数据透传, 调用BookServer中对应Handler.ServeGRPC转交给go-kit处理
func (s *BookServer) GetBookList(ctx context.Context, in *book.BookListParams) (*book.BookList, error) {
   _, rsp, err := s.bookListHandler.ServeGRPC(ctx, in)
   if err != nil {
      return nil, err
   }
   return rsp.(*book.BookList),err
}
//创建bookList的EndPoint
func makeGetBookListEndpoint() endpoint.Endpoint {
   return func(ctx context.Context, request interface{}) (interface{}, error) {
      //请求列表时返回 书籍列表
      bl := new(book.BookList)
      bl.BookList = append(bl.BookList, &book.BookInfo{BookId:1,BookName:"21天精通php"})
      bl.BookList = append(bl.BookList, &book.BookInfo{BookId:2,BookName:"21天精通java"})
      return bl,nil
   }
}
//创建bookInfo的EndPoint
func makeGetBookInfoEndpoint() endpoint.Endpoint {
   return func(ctx context.Context, request interface{}) (interface{}, error) {
      //请求详情时返回 书籍信息
      req := request.(*book.BookInfoParams)
      b := new(book.BookInfo)
      b.BookId = req.BookId
      b.BookName = "21天精通php"
      return b,nil
   }
}
func decodeRequest(_ context.Context, req interface{}) (interface{}, error) {
   return req, nil
}
func encodeResponse(_ context.Context, rsp interface{}) (interface{}, error) {
   return rsp, nil
}
func main() {
   var (
      //etcd服务地址
      etcdServer = "127.0.0.1:2379"
      //服务的信息目录
      prefix     = "/services/book/"
      //当前启动服务实例的地址
      instance   = "127.0.0.1:50052"
      //服务实例注册的路径
      key        = prefix + instance
      //服务实例注册的val
      value      = instance
      ctx        = context.Background()
      //服务监听地址
      serviceAddress = ":50052"
   )
   //etcd的连接参数
   options := etcdv3.ClientOptions{
      DialTimeout: time.Second * 3,
      DialKeepAlive: time.Second * 3,
   }
   //创建etcd连接
   client, err := etcdv3.NewClient(ctx, []string{etcdServer}, options)
   if err != nil {
      panic(err)
   }
   // 创建注册器
   registrar := etcdv3.NewRegistrar(client, etcdv3.Service{
      Key:   key,
      Value: value,
   }, log.NewNopLogger())
   // 注册器启动注册
   registrar.Register()
   bookServer := new(BookServer)
   bookListHandler := grpc_transport.NewServer(
      makeGetBookListEndpoint(),
      decodeRequest,
      encodeResponse,
   )
   bookServer.bookListHandler = bookListHandler
   bookInfoHandler := grpc_transport.NewServer(
      makeGetBookInfoEndpoint(),
      decodeRequest,
      encodeResponse,
   )
   bookServer.bookInfoHandler = bookInfoHandler
   ls, _ := net.Listen("tcp", serviceAddress)
   gs := grpc.NewServer(grpc.UnaryInterceptor(grpc_transport.Interceptor))
   book.RegisterBookServiceServer(gs, bookServer)
   gs.Serve(ls)
}

客户端代码

客户端流程

1、 连接注册中心

2、 获取提供的服务

3、 监听服务目录变化，目录变化更新本地缓存

4、 创建负载均衡器

5、 获取请求的 endPoint

完整代码

package main
import (
   "context"
   "github.com/go-kit/kit/sd/etcdv3"
   "time"
   "github.com/go-kit/kit/sd"
   "github.com/go-kit/kit/log"
   "github.com/go-kit/kit/endpoint"
   "io"
   "github.com/go-kit/kit/sd/lb"
   "grpc-test/pb"
   "fmt"
   "google.golang.org/grpc"
)
func main() {
   var (
      //注册中心地址
      etcdServer = "127.0.0.1:2379"
      //监听的服务前缀
      prefix     = "/services/book/"
      ctx        = context.Background()
   )
   options := etcdv3.ClientOptions{
      DialTimeout: time.Second * 3,
      DialKeepAlive: time.Second * 3,
   }
   //连接注册中心
   client, err := etcdv3.NewClient(ctx, []string{etcdServer}, options)
   if err != nil {
      panic(err)
   }
   logger := log.NewNopLogger()
   //创建实例管理器, 此管理器会Watch监听etc中prefix的目录变化更新缓存的服务实例数据
   instancer, err := etcdv3.NewInstancer(client, prefix, logger)
   if err != nil {
      panic(err)
   }
   //创建端点管理器， 此管理器根据Factory和监听的到实例创建endPoint并订阅instancer的变化动态更新Factory创建的endPoint
   endpointer := sd.NewEndpointer(instancer, reqFactory, logger)
   //创建负载均衡器
   balancer := lb.NewRoundRobin(endpointer)
   /**
   我们可以通过负载均衡器直接获取请求的endPoint，发起请求
   reqEndPoint,_ := balancer.Endpoint()
   */
   /**
   也可以通过retry定义尝试次数进行请求
   */
   reqEndPoint := lb.Retry(3, 3*time.Second, balancer)
   //现在我们可以通过 endPoint 发起请求了
   req := struct{}{}
   if _, err = reqEndPoint(ctx, req); err != nil {
      panic(err)
   }
}
//通过传入的 实例地址  创建对应的请求endPoint
func reqFactory(instanceAddr string) (endpoint.Endpoint, io.Closer, error) {
   return func(ctx context.Context, request interface{}) (interface{}, error) {
      fmt.Println("请求服务: ", instanceAddr)
      conn, err := grpc.Dial(instanceAddr, grpc.WithInsecure())
      if err != nil {
         fmt.Println(err)
         panic("connect error")
      }
      defer conn.Close()
      bookClient := book.NewBookServiceClient(conn)
      bi,_:=bookClient.GetBookInfo(context.Background(),&book.BookInfoParams{BookId:1})
      fmt.Println("获取书籍详情")
      fmt.Println("bookId: 1", " => ", "bookName:", bi.BookName)
      bl,_ := bookClient.GetBookList(context.Background(), &book.BookListParams{Page:1, Limit:10})
      fmt.Println("获取书籍列表")
      for _,b := range bl.BookList {
         fmt.Println("bookId:", b.BookId, " => ", "bookName:", b.BookName)
      }
      return nil,nil
   },nil,nil
} 

测试

请求测试

请求服务： 127.0.0.1:50052
获取书籍详情
bookId: 1  =>  bookName: 21天精通php
获取书籍列表
bookId: 1  =>  bookName: 21天精通php
bookId: 2  =>  bookName: 21天精通java

负载均衡测试

1、 修改server的注册监听端口，启动多个server

instance   = "127.0.0.1:50052"
serviceAddress = ":50052"

2、client发起多次请求

req := struct{}{}
for i := 1; i <= 8; i++ {
   if _, err = reqEndPoint(ctx, req); err != nil {
      panic(err)
   }
}

通过返回结果中记录的请求地址，我们可以看到已经按照轮询的方式请求不同的微服务实例。

请求服务:  127.0.0.1:50051
        获取书籍详情
        bookId: 1  =>  bookName: 21天精通php
        获取书籍列表
        bookId: 1  =>  bookName: 21天精通php
        bookId: 2  =>  bookName: 21天精通java
请求服务:  127.0.0.1:50052
        获取书籍详情
        bookId: 1  =>  bookName: 21天精通php
        获取书籍列表
        bookId: 1  =>  bookName: 21天精通php
        bookId: 2  =>  bookName: 21天精通java
请求服务:  127.0.0.1:50051
        获取书籍详情
        bookId: 1  =>  bookName: 21天精通php
        获取书籍列表
        bookId: 1  =>  bookName: 21天精通php
        bookId: 2  =>  bookName: 21天精通java
请求服务:  127.0.0.1:50052
        获取书籍详情
        bookId: 1  =>  bookName: 21天精通php
        获取书籍列表
        bookId: 1  =>  bookName: 21天精通php
        bookId: 2  =>  bookName: 21天精通java
请求服务:  127.0.0.1:50051
        获取书籍详情
        bookId: 1  =>  bookName: 21天精通php
        获取书籍列表
        bookId: 1  =>  bookName: 21天精通php
        bookId: 2  =>  bookName: 21天精通java
请求服务:  127.0.0.1:50052
        获取书籍详情
        bookId: 1  =>  bookName: 21天精通php
        获取书籍列表
        bookId: 1  =>  bookName: 21天精通php
        bookId: 2  =>  bookName: 21天精通java
请求服务:  127.0.0.1:50051
        获取书籍详情
        bookId: 1  =>  bookName: 21天精通php
        获取书籍列表
        bookId: 1  =>  bookName: 21天精通php
        bookId: 2  =>  bookName: 21天精通java
请求服务:  127.0.0.1:50052
        获取书籍详情
        bookId: 1  =>  bookName: 21天精通php
        获取书籍列表
        bookId: 1  =>  bookName: 21天精通php
        bookId: 2  =>  bookName: 21天精通java
Process finished with exit code 0

以上为个人经验，希望能给大家一个参考，也希望大家多多支持我们。如有错误或未考虑完全的地方，望不吝赐教。