使用带有 select 的通道时的 Goroutine 死锁

Goroutine deadlock when using a channel with select

我试图重写一个没有使用 selectWaitGroup 的工作程序,以便它可以实现 selectWaitGroup,但我遇到了一个问题,我找不到解决方案。似乎 goroutine 死锁发生了,因为 Manager 函数没有从 writer 通道获取数据,因此通道被阻塞 sending/receiving 并且程序锁定。

原始工作 Manager 功能,没有 select :

func Manager(list *[]Request, writerChan <-chan int) {
    ageIn, writersOpen := <-writerChan
    for {
        if writersOpen { // if writers channel is open

            Add(list, Request{Value: ageIn, Count: 1}) // putting new object to list
            ageIn, writersOpen = <-writerChan          // receiving new player from writer channe;

        } else {
            break
        }
    }
}

所以我有一个工作程序,但需要实施 WaitGroupselect,有更新的代码:

更新了 Manager 函数 select 实现:

func Manager(list *[]Request, writerChan <-chan int) {
    defer waitGroup.Done()
    for {
        select {
        case ageIn := <-writerChan:
            Add(list, Request{Value: ageIn, Count: 1}) // add player to list
        default:
            break
        }
    }
}

更新了 Main 函数 WaitGroup 实现:

var waitGroup sync.WaitGroup

func main() {
    list := ParallelList{List: make([]Request, 0)}
    readers, teams, players := ReadData("data.txt")
    writerChan := make(chan int)          //any2one writers channel
    writerFinishChan := make(chan int, 6) // channel to know when all writers are done writing

    waitGroup.Add(6)

    for i := 0; i < len(teams); i++ {
        go Writer(teams, teams[i], writerChan, writerFinishChan)
    }

    go Manager(&list.List, writerChan)
    waitGroup.Wait()
}

向writerChan发送数据的Writer函数

func Writer(teams [][]Player, team []Player, writerChan chan<- int,
    writerFinishChan chan int) {
    defer waitGroup.Done()
    count := len(team)
    for i := 0; i < count; i++ {
        writerChan <- team[i].Age
    }
    writerFinishChan <- 1 // when writer finishes writing, he puts 1 to the "writerFinishChan"

    if len(writerFinishChan) == len(teams) { // if all writers are done writing (the len should be equal to 6)
        close(writerChan)
    }
}

所以现在的问题是,在实施 selectWaitGroup 之后,我的程序不再正常工作,它给了我一个 "fatal error : goroutines asleep, deadlock"。

也许有人可以帮我解决这个问题?我很确定问题出在 Manager 函数中,它是 select

看起来您退出 Manager 函数的逻辑现在有所不同。在您等待通道关闭之前,但是现在您根本不检查。事实上 Manager 永远不会退出。这也意味着 WaitGroup 永远不会完成。

我认为Manager中的select没有必要。如果你要关闭频道,那么就在它上面范围:

for ageIn := range writerChan {
  Add(list, Request{Value: ageIn, Count: 1}) // putting new object to list
}

writerChan 关闭时,这将正确退出。