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@karupanerura
Last active May 22, 2020 06:56
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TCP stuck example
package main
import (
"bufio"
"io"
"log"
"net"
"sync"
"time"
)
func main() {
conn, err := net.Dial("tcp4", "localhost:8888")
if err != nil {
log.Fatal(err)
}
var wg sync.WaitGroup
go func() {
wg.Add(1)
defer wg.Done()
scope := time.Now().Truncate(time.Second)
var avg time.Duration
var cnt time.Duration
for {
startAt := time.Now()
startScope := startAt.Truncate(time.Second)
_, err := io.WriteString(conn, "Hello!\n")
if err != nil {
log.Printf("%v (startAt:%v)\n", err, startAt)
return
}
elapsed := time.Now().Sub(startAt)
if scope.Equal(startScope) {
avg = (cnt*avg + elapsed) / (cnt + 1)
cnt++
} else {
log.Printf("- %v (%d)\n", avg, cnt)
scope = startScope
avg = elapsed
cnt = 1
}
time.Sleep(300 * time.Microsecond)
}
}()
func() {
wg.Add(1)
defer wg.Done()
bufr := bufio.NewReader(conn)
for {
line, err := bufr.ReadString('\n')
if err != nil {
log.Println(err)
return
}
log.Printf("received: %s", line)
}
}()
wg.Wait()
}
2020/05/20 18:14:05 - 21.816µs (2186)
2020/05/20 18:14:06 - 21.257µs (2472)
2020/05/20 18:14:07 - 21.423µs (2472)
2020/05/20 18:14:07 received: Hello!
2020/05/20 18:14:08 - 21.736µs (2474)
2020/05/20 18:14:09 - 21.771µs (2476)
2020/05/20 18:14:10 - 21.649µs (2473)
2020/05/20 18:14:10 received: Hello!
2020/05/20 18:14:11 - 21.389µs (2448)
2020/05/20 18:14:12 - 21.682µs (2473)
2020/05/20 18:14:13 - 21.505µs (2482)
2020/05/20 18:14:13 received: Hello!
2020/05/20 18:14:14 - 21.673µs (2473)
2020/05/20 18:14:15 - 21.43µs (2481)
2020/05/20 18:14:16 - 21.533µs (2461)
2020/05/20 18:14:16 received: Hello!
2020/05/20 18:14:17 - 21.527µs (2469)
2020/05/20 18:14:18 - 22.538µs (2457)
2020/05/20 18:14:19 - 21.3µs (2477)
2020/05/20 18:14:19 received: Hello!
2020/05/20 18:14:20 - 22.237µs (2468)
2020/05/20 18:14:21 - 22.061µs (2469)
2020/05/20 18:14:22 - 22.01µs (2463)
2020/05/20 18:14:22 received: Hello!
2020/05/20 18:14:23 - 21.711µs (2483)
2020/05/20 18:14:24 - 22.5µs (2469)
2020/05/20 18:14:25 - 21.953µs (2467)
2020/05/20 18:14:25 received: Hello!
2020/05/20 18:14:26 - 22.39µs (2457)
2020/05/20 18:14:27 - 22.322µs (2468)
2020/05/20 18:14:28 - 20.327µs (2470)
2020/05/20 18:14:28 received: Hello!
2020/05/20 18:14:29 - 12.092µs (2524)
2020/05/20 18:14:30 - 12.423µs (2515)
2020/05/20 18:14:31 - 12.026µs (2520)
2020/05/20 18:14:31 received: Hello!
2020/05/20 18:14:32 - 12.367µs (2519)
2020/05/20 18:14:33 - 12.221µs (2581)
2020/05/20 18:14:34 - 12.579µs (2537)
2020/05/20 18:14:34 received: Hello!
2020/05/20 18:14:35 - 12.464µs (2521)
2020/05/20 18:14:36 - 12.734µs (2521)
2020/05/20 18:14:37 received: Hello!
2020/05/20 18:14:40 received: Hello!
2020/05/20 18:14:43 received: Hello!
2020/05/20 18:14:46 received: Hello!
2020/05/20 18:14:49 received: Hello!
2020/05/20 18:14:52 received: Hello!
2020/05/20 18:14:55 received: Hello!
2020/05/20 18:14:57 read tcp4 127.0.0.1:59345->127.0.0.1:8888: read: connection reset by peer
2020/05/20 18:14:57 write tcp4 127.0.0.1:59345->127.0.0.1:8888: write: broken pipe (startAt:2020-05-20 18:14:36.058589 +0900 JST m=+31.945740248)
package main
import (
"bufio"
"io"
"log"
"net"
"time"
)
func main() {
l, err := net.Listen("tcp4", "localhost:8888")
if err != nil {
log.Fatal(err)
}
for {
c, err := l.Accept()
if err != nil {
log.Println(err)
return
}
go func(c net.Conn) {
bufr := bufio.NewReader(c)
for {
line, err := bufr.ReadString('\n')
if err != nil {
log.Println(err)
break
}
time.Sleep(3 * time.Second) # emulate to delay receiving/processing the data
_, err = io.WriteString(c, line)
if err != nil {
log.Println(err)
break
}
}
err := c.Close()
if err != nil {
log.Println(err)
}
}(c)
}
}
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