我已经在golang中实现了一个演示tcp聊天服务器,它工作正常,但每当用户断开连接,我尝试写一条消息到广播频道让其他用户知道用户已经断开它的阻止,并且不会进一步处理来自其他客户端的任何新消息,因为它的非缓冲通道前往:与去频道的死锁问题,并选择
我已经评论了代码并解释了它可以通过它,我不知道为什么代码块,我已经写了封邮件
- 我要写一个通道
- 我写TH E通道
- 我从通道
阅读和消息井井有条还是我的味精通道块。 Ps:如果我使用缓冲通道,代码不会阻塞,但我想知道我的代码卡在哪里。 我也尝试运行代码才能使用标志-RACE,但没有帮助
package main
import (
"fmt"
"io"
"net"
"sync"
)
func main() {
msg := make(chan string) //broadcast channel (making it buffered channel the problem goes away)
allConn := make(map[net.Conn]int) //Collection of incoming connections for broadcasting the message
disConn := make(chan net.Conn) //client disconnect channel
newConn := make(chan net.Conn) //new client connection channel
mutext := new(sync.RWMutex) //mux to assign unique id to incoming connections
i := 0
listener, err := net.Listen("tcp", "127.0.0.1:8081")
checkErr(err)
fmt.Println("Tcp server started at 127.0.0.1:8081")
//Accept incoming connections and store them in global connection store allConn
go func() {
for {
conn, err := listener.Accept()
checkErr(err)
mutext.Lock()
allConn[conn] = i
i++
mutext.Unlock()
newConn <- conn
}
}()
for {
select {
//Wait for a new client message to arrive and broadcast the message
case umsg := <-msg:
fmt.Println("Broadcast Channel: Already Read")
bmsg := []byte(umsg)
for conn1, _ := range allConn {
_, err := conn1.Write(bmsg)
checkErr(err)
}
//Handle client disconnection [disConn]
case conn := <-disConn:
mutext.RLock()
fmt.Println("user disconneting", allConn[conn])
mutext.RUnlock()
delete(allConn, conn)
fmt.Println("Disconnect: About to Write")
//this call results in deadlock even when channel is empty, buffered channel resolves the issue
//need to know why
msg <- fmt.Sprintf("Disconneting", allConn[conn])
fmt.Println("Disconnect: Already Written")
//Read client incoming message and put it on broadcasting channel and upon disconnect put on it disConn channel
case conn := <-newConn:
go func(conn net.Conn) {
for {
buf := make([]byte, 64)
n, err := conn.Read(buf)
if err != nil {
if err == io.EOF {
disConn <- conn
break
}
}
fmt.Println("Client: About to Write")
msg <- string(buf[0:n])
fmt.Println("Client: Already Written")
}
}(conn)
mutext.RLock()
fmt.Println("User Connected", allConn[conn])
mutext.RUnlock()
}
}
}
func checkErr(err error) {
if err != nil {
panic(err)
}
}
有关详细信息,请参阅https://golang.org/ref/mem#tmp_7(“通道通信”部分,如果锚点更改)。 – Vatine