GO语言实现一个TCP负载均衡器需要多少代码？-Go服务器开发

实现一个基本的TCP负载均衡器大约需要150-300行Go代码。以下是一个简化版的实现示例：

package main

import (
    "fmt"
    "log"
    "net"
    "sync"
    "time"
)

type Backend struct {
    addr string
    alive bool
    mu sync.RWMutex
}

type LoadBalancer struct {
    backends []*Backend
    current int
    mu sync.Mutex
}

func (b *Backend) IsAlive() bool {
    b.mu.RLock()
    defer b.mu.RUnlock()
    return b.alive
}

func (b *Backend) SetAlive(alive bool) {
    b.mu.Lock()
    defer b.mu.Unlock()
    b.alive = alive
}

func NewLoadBalancer(backendAddrs []string) *LoadBalancer {
    lb := &LoadBalancer{}
    for _, addr := range backendAddrs {
        lb.backends = append(lb.backends, &Backend{
            addr: addr,
            alive: true,
        })
    }
    go lb.HealthCheck()
    return lb
}

func (lb *LoadBalancer) GetNextBackend() *Backend {
    lb.mu.Lock()
    defer lb.mu.Unlock()
    
    for i := 0; i < len(lb.backends); i++ {
        lb.current = (lb.current + 1) % len(lb.backends)
        if backend := lb.backends[lb.current]; backend.IsAlive() {
            return backend
        }
    }
    return nil
}

func (lb *LoadBalancer) HealthCheck() {
    for {
        for _, backend := range lb.backends {
            alive := lb.checkBackend(backend.addr)
            backend.SetAlive(alive)
        }
        time.Sleep(10 * time.Second)
    }
}

func (lb *LoadBalancer) checkBackend(addr string) bool {
	conn, err := net.DialTimeout("tcp", addr, 2*time.Second)
	if err != nil {
		return false
	}
	defer conn.Close()
	return true
}

func (lb *LoadBalancer) HandleConnection(conn net.Conn) {
	defer conn.Close()
	
	backend := lb.GetNextBackend()
	if backend == nil {
		log.Println("No available backends")
		return
	}
	
	backendConn, err := net.Dial("tcp", backend.addr)
	if err != nil {
		log.Printf("Failed to connect to backend %s: %v", backend.addr, err)
		return
	}
	defer backendConn.Close()

	go func() { io.Copy(backendConn, conn) }()
	io.Copy(conn, backendConn)
}

func main() {
	backends := []string{
		"localhost:8081",
		"localhost:8082",
		"localhost:8083",
	}
	
	listener, err := net.Listen("tcp", ":80")
	if err != nil {
	    log.Fatal(err)
	    return 
     }
     
     fmt.Println("TCP Load Balancer started on :80")
     defer listener.Close()

     loadBalancer := NewLoadBalancer(backends)

     for { 
         clientConn ,err:=listener.Accept()  
         if err!=nil{  
             continue  
         }  
         go loadBalancer.HandleConnection(clientConn )  
     }  
}

主要组件说明：