golang 实现一个负载均衡案例(随机,轮训)

package balance
type Instance struct {
    host string
    port int
}
func NewInstance(host string, port int) *Instance {
    return &Instance{
        host: host,
        port: port,
    }
}
func (p *Instance) GetHost() string {
    return p.host
}
func (p *Instance) GetPort() int {
    return p.port
}

package balance
type Balance interface {
    /**
    *负载均衡算法
    */
    DoBalance([] *Instance,...string) (*Instance,error)
} 

package balance
import (
    "errors"
    "math/rand"
)
func init()  {
    RegisterBalance("random",&RandomBalance{})
}
type RandomBalance struct {
}
func (p *RandomBalance) DoBalance(insts [] *Instance,key...string) (inst *Instance, err error) {
    if len(insts) == 0 {
        err = errors.New("no instance")
        return
    }
    lens := len(insts)
    index := rand.Intn(lens)
    inst = insts[index]
    return
}

package balance
import (
    "errors"
)
func init() {
    RegisterBalance("round", &RoundRobinBalance{})
}
type RoundRobinBalance struct {
    curIndex int
}
func (p *RoundRobinBalance) DoBalance(insts [] *Instance, key ...string) (inst *Instance, err error) {
    if len(insts) == 0 {
        err = errors.New("no instance")
        return
    }
    lens := len(insts)
    if p.curIndex >= lens {
        p.curIndex = 0
    }
    inst = insts[p.curIndex]
    p.curIndex++
    return
}

package balance
import (
    "fmt"
)
type BalanceMgr struct {
    allBalance map[string]Balance
}
var mgr = BalanceMgr{
    allBalance: make(map[string]Balance),
}
func (p *BalanceMgr) registerBalance(name string, b Balance) {
    p.allBalance[name] = b
}
func RegisterBalance(name string, b Balance) {
    mgr.registerBalance(name, b)
}
func DoBalance(name string, insts []*Instance) (inst *Instance, err error) {
    balance, ok := mgr.allBalance[name]
    if !ok {
        err = fmt.Errorf("not fount %s", name)
        fmt.Println("not found ",name)
        return
    }
    inst, err = balance.DoBalance(insts)
    if err != nil {
        err = fmt.Errorf(" %s erros", name)
        return
    }
    return
}

func main() {
    var insts []*balance.Instance
    for i := 0; i < 10; i++ {
        host := fmt.Sprintf("192.168.%d.%d", rand.Intn(255), rand.Intn(255))
        port, _ := strconv.Atoi(fmt.Sprintf("880%d", i))
        one := balance.NewInstance(host, port)
        insts = append(insts, one)
    }
    var name = "round"
    if len(os.Args) > 1 {
        name = os.Args[1]
    }
    for {
        inst, err := balance.DoBalance(name, insts)
        if err != nil {
            fmt.Println("do balance err")
            time.Sleep(time.Second)
            continue
        }
        fmt.Println(inst)
        time.Sleep(time.Second)
    }
}

package add
import (
    "awesomeProject/test/balance"
    "fmt"
    "math/rand"
    "hash/crc32"
)
func init() {
    balance.RegisterBalance("hash", &HashBalance{})
}
type HashBalance struct {
    key string
}
func (p *HashBalance) DoBalance(insts [] *balance.Instance, key ...string) (inst *balance.Instance, err error) {
    defKey := fmt.Sprintf("%d", rand.Int())
    if len(key) > 0 {
        defKey = key[0]
    }
    lens := len(insts)
    if lens == 0 {
        err = fmt.Errorf("no balance")
        return
    }
    hashVal := crc32.Checksum([]byte(defKey), crc32.MakeTable(crc32.IEEE))
    index := int(hashVal) % lens
    inst = insts[index]
    return
}

upstream lb{
#负载均衡的grpc服务器地址
  server 127.0.0.1:50052;
  server 127.0.0.1:50053;
  server 127.0.0.1:50054;
  #keepalive 500;#这个东西是nginx和rpc服务器群保持长连接的总数，设置可以提高效率，同时避免nginx到rpc服务器之间默认是短连接并发过后造成time_wait过多
}
server {
  listen       9527     http2;
  access_log  /var/log/nginx/host.access.log  main;
  http2_max_requests 10000;#这里默认是1000，并发量上来会报错，因此设置大一点
  #grpc_socket_keepalive on;#这个东西nginx1.5过后支持
  location / {
    grpc_pass grpc://lb;
    error_page 502 = /error502grpc;
  }
  location = /error502grpc {
    internal;
    default_type application/grpc;
    add_header grpc-status 14;
    add_header grpc-message "Unavailable";
    return 204;
  }
}

syntax = "proto3"; // 指定proto版本
package grpctest;     // 指定包名
// 定义Hello服务
service Hello {
    // 定义SayHello方法
    rpc SayHello(HelloRequest) returns (HelloReply) {}
}
// HelloRequest 请求结构
message HelloRequest {
    string name = 1;
}
// HelloReply 响应结构
message HelloReply {
    string message = 1;
}

package main
import (
 pb "protobuf/grpctest" // 引入proto包
 "golang.org/x/net/context"
 "google.golang.org/grpc"
 "google.golang.org/grpc/grpclog"
 "fmt"
 "time"
)
const (
 // Address gRPC服务地址
 Address = "127.0.0.1:9527"
)
func main() {
 // 连接
 conn, err := grpc.Dial(Address, grpc.WithInsecure())
 if err != nil {
  grpclog.Fatalln(err)
 }
 defer conn.Close()
 // 初始化客户端
 c := pb.NewHelloClient(conn)
 reqBody := new(pb.HelloRequest)
 reqBody.Name = "gRPC"
 // 调用方法
 for{
  r, err := c.SayHello(context.Background(), reqBody)
  if err != nil {
   grpclog.Fatalln(err)
  }
  fmt.Println(r.Message)
  time.Sleep(time.Second)
 }
}

package main
import (
 "net"
 "fmt"
 pb "protobuf/grpctest" // 引入编译生成的包
 "golang.org/x/net/context"
 "google.golang.org/grpc"
 "google.golang.org/grpc/grpclog"
)
const (
 // Address gRPC服务地址
 Address = "127.0.0.1:50052"
 //Address = "127.0.0.1:50053"
 //Address = "127.0.0.1:50054"
)
var HelloService = helloService{}
type helloService struct{}
func (this helloService) SayHello(ctx context.Context,in *pb.HelloRequest)(*pb.HelloReply,error){
 resp := new(pb.HelloReply)
 resp.Message = Address+" hello"+in.Name+"."
 return resp,nil
}
func main(){
 listen,err:=net.Listen("tcp",Address)
 if err != nil{
  grpclog.Fatalf("failed to listen: %v", err)
 }
 s:=grpc.NewServer()
 pb.RegisterHelloServer(s,HelloService)
 grpclog.Println("Listen on " + Address)
 s.Serve(listen)
}