我有 TCP 服務(wù)器和客戶端，簡單 TCP 服務(wù)器將只接收傳入數(shù)據(jù)并打印它，客戶端將不斷創(chuàng)建套接字連接并在循環(huán)中將數(shù)據(jù)發(fā)送到 TCP 服務(wù)器。我得到的信息是，如果 TCP 連接正確關(guān)閉，這個(gè)過程應(yīng)該繼續(xù)進(jìn)行而不會(huì)出現(xiàn)任何崩潰。但是在從客戶端接收到服務(wù)器的一些數(shù)據(jù)后，客戶端因錯(cuò)誤而崩潰total times data send: 16373panic: runtime error: invalid memory address or nil pointer dereference[signal SIGSEGV: segmentation violation code=0x1 addr=0x0 pc=0x10d7594]goroutine 1 [running]:main.sendData()/Users/apple/Desktop/Personal/umbrellaserver/src/tests/clinet.go:178 +0xb4main.main()/Users/apple/Desktop/Personal/umbrellaserver/src/tests/clinet.go:170 +0x2aexit status 2服務(wù)器.gopackage mainimport ( "bufio" "fmt" "net" "sync")var wg sync.WaitGroupvar count = 0var timeX string = ""var connQueue = make(chan string)func main() { tcpListner := startTCPConnection() incomingTCPListener(tcpListner)}//startTCPConnectionfunc startTCPConnection() net.Listener { tcpListner, tcpConnectonError := net.Listen("tcp", "localhost:3000") if tcpConnectonError != nil { print(tcpConnectonError) return } return tcpListner}//incomingTCPListenerfunc incomingTCPListener(tcpListner net.Listener) { for { incomingConnection, incomingConnectionError := tcpListner.Accept() if incomingConnectionError != nil { print(incomingConnectionError) return } wg.Add(1) go processIncomingRequest(incomingConnection) wg.Wait() }}//processIncomingRequestfunc processIncomingRequest(connection net.Conn) { defer connection.Close() var scanner = bufio.NewScanner(connection) var blob = "" for scanner.Scan() { fmt.Println("sadd") text := scanner.Text() blob += text } print(blob) count++ fmt.Println("totalCount", count) wg.Done()}有什么辦法可以避免這種崩潰，讓它一直運(yùn)行下去嗎？ 我是 Go 的新手，所以如果我犯了任何愚蠢的錯(cuò)誤，我很抱歉。
3 回答
鴻蒙傳說
TA貢獻(xiàn)1865條經(jīng)驗(yàn) 獲得超7個(gè)贊
首先，如果你想打印到 stderr，（即你的打印調(diào)用），我建議使用 fmt 庫
fmt.Fprintln(os.Stderr, "hello world")
為什么：因?yàn)榇蛴」δ懿荒鼙ＷC留在語言中。1個(gè)
其次，通常的做法是將錯(cuò)誤名稱命名為err，而不必將錯(cuò)誤拼寫為tcpConnectionError.
connection, connectionError := net.Dial("tcp", "localhost:3000")第三，由于您在服務(wù)器中使用 tcp，因此正在偵聽 ipv6 和 ipv4。我至少在 Windows 機(jī)器上觀察到連接打開兩個(gè)連接，一個(gè)用于 ipv4 和 ipv6，然后丟棄 ipv6 連接以支持 ipv4。
最后，當(dāng) TCP 連接關(guān)閉時(shí)，端口不能立即重新使用，因?yàn)椴僮飨到y(tǒng)必須等待 TIME_WAIT 間隔（最大段生存期，MSL）的持續(xù)時(shí)間。
您的客戶端代碼正在打開大量非常短暫的 tcp 連接，并且根據(jù)您臨時(shí)端口范圍的范圍，您的代碼可能會(huì)或可能不會(huì)崩潰。從16373的數(shù)量來看，你有默認(rèn)范圍。2個(gè)
>> sysctl net.inet.ip.portrange.first net.inet.ip.portrange.last
net.inet.ip.portrange.first: 49152
net.inet.ip.portrange.last: 65535
最后，
如果您想避免因端口用完而導(dǎo)致崩潰：
1. 增加端口的臨時(shí)范圍
2. 使用 Docker，容器在它們自己的網(wǎng)絡(luò)上，因此使用一組不同的端口繞過有限的端口范圍。
3. 在您的客戶端代碼中引入一個(gè)自動(dòng)收?qǐng)?bào)機(jī)，以模擬每 x 秒/分鐘的連接
package main
import (
"fmt"
"net"
"time"
)
var count = 0
func testJSON2() string {
return `Contrary to popular belief, Lorem Ipsum is not simply random text. It has roots in a piece of classical Latin literature from 45 BC, making it over 2000 years old. Richard McClintock, a Latin professor at Hampden-Sydney College in Virginia, looked up one of the more obscure Latin words, consectetur, from a Lorem Ipsum passage, and going through the cites of the word in classical literature, discovered the undoubtable source. Lorem Ipsum comes from sections 1.10.32 and 1.10.33 of "de Finibus Bonorum et Malorum" (The Extremes of Good and Evil) by Cicero, written in 45 BC. This book is a treatise on the theory of ethics, very popular during the Renaissance. The first line of Lorem Ipsum, "Lorem ipsum dolor sit amet..", comes from a line in section 1.10.32. The standard chunk of Lorem Ipsum used since the 1500s is reproduced below for those interested. Sections 1.10.32 and 1.10.33 from "de Finibus Bonorum et Malorum" by Cicero are also reproduced in their exact original form, accompanied by English versions from the 1914 translation by H. Rackham.`
}
func main() {
max := 1000
timer1 := time.NewTicker(5 * time.Second)
i := 0
for range timer1.C {
sendData()
if i == max {
timer1.Stop()
}
i++
}
}
func sendData() {
connection, connectionError := net.Dial("tcp", "localhost:3000")
fmt.Println(connection.LocalAddr())
if connectionError != nil {
fmt.Println(connectionError)
return
}
newmessage := testJSON2()
connection.Write([]byte(newmessage + "\n"))
count++
fmt.Println(count)
err := connection.Close()
if err != nil {
fmt.Println(err)
}
}
慕姐4208626
TA貢獻(xiàn)1852條經(jīng)驗(yàn) 獲得超7個(gè)贊
if connectionError != nil {
fmt.Println(connectionError)
return
}
defer connection.Close()
defer connection.Close() 應(yīng)該在錯(cuò)誤檢查之后，因?yàn)檫B接變量可以是 nil incase 撥號(hào)返回時(shí)出現(xiàn)一些錯(cuò)誤。
暮色呼如
TA貢獻(xiàn)1853條經(jīng)驗(yàn) 獲得超9個(gè)贊
package main
import (
"bufio"
"fmt"
"net"
"sync"
)
var wg sync.WaitGroup
var count = 0
var timeX string = ""
var connQueue = make(chan string)
func main() {
tcpListner := startTCPConnection()
incomingTCPListener(tcpListner)
wg.Wait()
}
//startTCPConnection
func startTCPConnection() net.Listener {
tcpListner, tcpConnectonError := net.Listen("tcp", "localhost:3000")
if tcpConnectonError != nil {
print(tcpConnectonError)
// return
log.Fatal(tcpConnectonError)
}
return tcpListner
}
//incomingTCPListener
func incomingTCPListener(tcpListner net.Listener) {
for {
incomingConnection, incomingConnectionError := tcpListner.Accept()
if incomingConnectionError != nil {
print(incomingConnectionError)
return
}
wg.Add(1)
go processIncomingRequest(incomingConnection)
// wg.Wait()
}
}
//processIncomingRequest
func processIncomingRequest(connection net.Conn) {
defer connection.Close()
var scanner = bufio.NewScanner(connection)
var blob = ""
for scanner.Scan() {
fmt.Println("sadd")
text := scanner.Text()
blob += text
}
print(blob)
count++
fmt.Println("totalCount", count)
wg.Done()
}
問題出在server.go。我的猜測是您通過在 incomingTCPListener() 函數(shù)中調(diào)用 wg.Wait() 而不是 main() 來耗盡端口。此外，在 startTCPConnection() 函數(shù)中直接返回將導(dǎo)致編譯器錯(cuò)誤。
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