package main
import (
"net"
"time"
)
func initProxy() {
pLog.Infof("Proxying %s -> %s\n", pConfig.Bind, pConfig.Backend) //输出服务地址 后端服务地址列表
server, err := net.Listen("tcp", pConfig.Bind) //建立tcp连接 if err != nil { pLog.Fatal(err)
}
waitQueue := make(chan net.Conn, pConfig.WaitQueueLen) //建立连接队列 队列默认等待队列长度---channel net.Conn ==控制最大排队队列
availPools := make(chan bool, pConfig.MaxConn) //建立最大连接数--channel bool=== 控制最大连接数
for i := 0; i < pConfig.MaxConn; i++ { // availPools <- true
}
go loop(waitQueue, availPools)
for { connection, err := server.Accept() //等待获取下一次连接
if err != nil { pLog.Error(err)
} else { pLog.Infof("Received connection from %s.\n", connection.RemoteAddr()) waitQueue <- connection
}
}
}
func loop(waitQueue chan net.Conn, availPools chan bool) { for connection := range waitQueue { //循环等待队列中 排队等待需要处理的数据--连接 <-availPools //从通道中 连接池中取出一个
go func(connection net.Conn) { handleConnection(connection)
availPools <- true //使用结束放回连接池中 目的控制连接数量 通道阻塞特性
pLog.Infof("Closed connection from %s.\n", connection.RemoteAddr()) }(connection)
}
}
func handleConnection(connection net.Conn) { defer connection.Close()
bksvr, ok := getBackendSvr(connection)
if !ok { return
}
remote, err := net.Dial("tcp", bksvr.svrStr)
if err != nil { pLog.Error(err)
bksvr.failTimes++
return
}
//等待双向连接完成
complete := make(chan bool, 2)
oneSide := make(chan bool, 1)
otherSide := make(chan bool, 1)
go pass(connection, remote, complete, oneSide, otherSide)
go pass(remote, connection, complete, otherSide, oneSide)
<-complete
<-complete
remote.Close()
}
// copy Content two-way
func pass(from net.Conn, to net.Conn, complete chan bool, oneSide chan bool, otherSide chan bool) { var err error
var read int
bytes := make([]byte, 256)
for { select {
case <-otherSide:
complete <- true
return
default:
from.SetReadDeadline(time.Now().Add(time.Duration(pConfig.Timeout) * time.Second))
read, err = from.Read(bytes)
if err != nil { complete <- true
oneSide <- true
return
}
to.SetWriteDeadline(time.Now().Add(time.Duration(pConfig.Timeout) * time.Second))
_, err = to.Write(bytes[:read])
if err != nil { complete <- true
oneSide <- true
return
}
}
}
}