[英]Is this func possible to cause goroutine leak
func startTimer(ctx context.Context, intervalTime int) {
intervalChan := make(chan bool)
go func() {
for {
select {
case <-ctx.Done():
return
case <-time.After(time.Second * time.Duration(intervalTime)):
intervalChan <- true
}
}
}()
for {
select {
case <-ctx.Done():
return
case <-intervalChan:
doSomething()
}
}
Hi,I write a func as above and want to know is it possible to cause goroutine leak. 嗨,我如上所述编写了一个func,想知道是否有可能导致goroutine泄漏。
For example, the first select statement sends a true to intervalChan, then the second select statement receives Done flag from ctx.Done() and return. 例如,第一个选择语句将true发送给intervalChan,然后第二个选择语句从ctx.Done()接收Done标志并返回。 Will the goroutine be block forever? goroutine会永远被封锁吗?
I cannot replicate this behaviour every time but could be some leak. 我无法每次都复制此行为,但可能会出现一些泄漏。 If doSomething
do some heavy computation, meanwhile goroutine is blocked on intervalChan <- true
since it cannot push into the channel. 如果doSomething
做一些繁重的计算,则goroutine在intervalChan <- true
-true上被阻塞,因为它无法推送到通道中。 After doSomething
finish execution and context was cancelled, startTimer exists before goroutine and this will lead into blocked goroutine, because there isn't any consumer of intervalChan
. 在doSomething
完成执行并且取消了上下文之后,startTimer在goroutine之前存在,这将导致阻塞的goroutine,因为没有intervalChan
使用者。
go version go1.8.3 darwin/amd64
package main
import (
"context"
"fmt"
"time"
)
func startTimer(ctx context.Context, intervalTime int) {
intervalChan := make(chan bool)
go func() {
for {
select {
case <-ctx.Done():
fmt.Println("Done from inside of goroutine.")
return
case <-time.After(time.Second * time.Duration(intervalTime)):
fmt.Println("Interval reached.")
intervalChan <- true
}
}
}()
for {
select {
case <-ctx.Done():
fmt.Println("Done from startTimer.")
return
case <-intervalChan:
time.Sleep(10 * time.Second)
fmt.Println("Done")
}
}
}
func main() {
ctx, cancel := context.WithTimeout(context.Background(), 5*time.Second)
defer cancel()
startTimer(ctx, 2)
}
The only place your first goroutine could be blocked indefinitely is in intervalChan <- true
. 您的第一个goroutine唯一可以无限期阻止的地方是intervalChan <- true
。 Put it in another select block to be able to cancel that send: 将其放在另一个选择块中可以取消该发送:
go func() {
for {
select {
case <-ctx.Done():
return
case <-time.After(time.Second * time.Duration(intervalTime)):
select {
case <-ctx.Done():
return
case intervalChan <- true:
}
}
}
}()
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