go语言实现tcp四层负载的开源软件，只需要tcp四层负载-Go服务器开发

以下是几个用Go语言实现TCP四层负载均衡的开源软件：

1. Traefik

虽然主要用作HTTP反向代理，但支持TCP四层负载均衡

# traefik.yml 配置示例
entryPoints:
  web:
    address: ":80"
  tcp:
    address: ":3306"

tcp:
  routers:
    mysql-router:
      entryPoints: ["tcp"]
      rule: "HostSNI(`*`)"
      service: mysql-service
  
  services:
    mysql-service:
      loadBalancer:
        servers:
        - address: "192.168.1.10:3306"
        - address: "192.168.1.11:3306"

2. HAProxy (Go版本)

虽然不是纯Go，但有Go语言实现的变体

// Go-HAProxy 简化示例
type TCPLoadBalancer struct {
    backends []string
    current  int64
}

func (lb *TCPLoadBalancer) ServeTCP(conn net.Conn) {
    backend := lb.getNextBackend()
    backendConn, err := net.Dial("tcp", backend)
    if err != nil {
        // 错误处理
        return
    }
    
    go io.Copy(backendConn, conn)
    io.Copy(conn, backendConn)
}

3. GLB (Go Load Balancer)

专门为TCP四层负载设计

package main

import (
    "net"
    "sync/atomic"
)

type GLB struct {
    servers []string
    counter uint64
}

func (g *GLB) NextServer() string {
    n := atomic.AddUint64(&g.counter, 1)
    return g.servers[(int(n)-1)%len(g.servers)]
}

func (g *GLB) HandleConnection(clientConn net.Conn) {
    defer clientConn.Close()
    
    serverAddr := g.NextServer()
    serverConn, err := net.Dial("tcp", serverAddr)
    if err != nil {
        return
    }
    defer serverConn.Close()
    
    // TCP流量转发
    go io.Copy(serverConn, clientConn)
    io.Copy(clientConn, serverConn)
}

4. 简单自实现示例

package main

import (
    "flag"
    "fmt"
    "io"
    "log"
    "net"
    "sync/atomic"
)

type TCPLoadBalancer struct {
    listenAddr string
    backends   []string
    counter    uint64
}

func NewTCPLoadBalancer(listen string, backends []string) *TCPLoadBalancer {
    return &TCPLoadBalancer{
        listenAddr: listen,
        backends:   backends,
        counter:    0,
        
func (lb *TCPLoadBalancer) getNextBackend() string {
    
n := atomic.AddUint64(&lb.counter, 
return lb.backends[int(n)%len(lb.backends)]
}

func (lb *TCPLoadBalancer) handleConnection(clientConn net.Conn) {defer clientConn.Close()

backend := lb.getNextBackend()
backendConn, err := net.Dial("tcp", backend)
if err != nil {log.Printf("Failed to connect to backend %s: %v", backend, err)
return
    
defer backend
    
// 双向数据转发go io.Copy(backend
    
io.Copy(client
    
}

func (lb *TCPLoadBalancer) Start() error {listener, err := net.Listen("tcp", lb.listenAddr)
if err != nil {return fmt.Errorf("failed to listen on %s: %v", lb.listenAddr, err)}
defer listener.Close()

log.Printf("TCP Load Balancer listening on %s", lb.listenAddr)

for {client
    
err := listener.Accept()
if err != nil {log.Printf("Accept error: %v", err)
continue}
go lb.handleConnection(client
    
}}

func main() {var listenAddr stringvar backendsStr string

flag.StringVar(&listenAddr, "listen", ":8080", "监听地址")
flag.StringVar(&backendsStr, "backends", "localhost:8081,localhost:8082", 
"后端服务器列表，逗号分隔")
flag.Parse()

backends := strings.Split(backendsStr, ",")

lb := NewTCPLoadBalancer(listenAddr, backends)

if err := lb.Start(); err != nil {log.Fatalf("Failed to start load balancer: %v", err)}}