How to use the sync.WaitGroup to execute all the goroutine?

huangapple
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英文:

How to use the sync.WaitGroup to execute all the goroutine?

问题

目前我正在将所有的值推送到通道中，并从中读取并对其进行平方处理。
我想避免使用time.Sleep(2000 * time.Millisecond)，因为它会阻塞程序执行2秒钟，而我希望每个goroutine都能处理并等待其执行，然后退出程序。我对golang有点生疏，所以现在问这个基本问题:(。有人可以帮我吗？

  1. package main
  3. import (
  4. 	"fmt"
  5. 	"sync"
  6. 	"time"
  7. )
  9. func doSquare(num int) int {
  10. 	return num * num
  11. }
  13. var wg sync.WaitGroup
  15. func main() {
  17. 	wg.Add(1)
  18. 	st := []int{1, 2, 3, 4, 5, 6, 7, 8, 9, 10}
  19. 	quit := make(chan bool)
  20. 	ch := make(chan int)
  21. 	go func() {
  22. 		for i := range st {
  23. 			ch <- i
  24. 		}
  25. 	}()
  27. 	go func() {
  28. 		for {
  29. 			select {
  30. 			case x := <-ch:
  31. 				fmt.Println(doSquare(x))
  32. 				// return
  34. 			case <-quit:
  35. 				wg.Done()
  36. 			default:
  37. 				// fmt.Println("---")
  38. 				// do something
  39. 			}
  40. 		}
  41. 	}()
  43. 	quit <- true
  45. 	wg.Wait()
  46. 	time.Sleep(2000 * time.Millisecond)
  47. }

请注意，我只翻译了代码部分，其他内容不包括在内。

英文:

Currently I am pushing all the values to the channel and reading from it and doing the square of it.
I want to avoid using time.Sleep(2000 * time.Millisecond) since it's blocking the execution for 2 seconds instead I want every goroutine to process and wait for its execution and then exit the program. I just got out of touch with golang so asking this basic question now :(. Can anyone help me with this?

  1. package main
  3. import (
  4. 	&quot;fmt&quot;
  5. 	&quot;sync&quot;
  6. 	&quot;time&quot;
  7. )
  9. func doSquare(num int) int {
  10. 	return num * num
  11. }
  13. var wg sync.WaitGroup
  15. func main() {
  17. 	wg.Add(1)
  18. 	st := []int{1, 2, 3, 4, 5, 6, 7, 8, 9, 10}
  19. 	quit := make(chan bool)
  20. 	ch := make(chan int)
  21. 	go func() {
  22. 		for i := range st {
  23. 			ch &lt;- i
  24. 		}
  25. 	}()
  27. 	go func() {
  28. 		for {
  29. 			select {
  30. 			case x := &lt;-ch:
  31. 				fmt.Println(doSquare(x))
  32. 				// return
  34. 			case &lt;-quit:
  35. 				wg.Done()
  36. 			default:
  37. 				// fmt.Println(&quot;---&quot;)
  38. 				// do something
  39. 			}
  40. 		}
  41. 	}()
  43. 	quit &lt;- true
  45. 	wg.Wait()
  46. 	time.Sleep(2000 * time.Millisecond)
  47. }

答案1

得分: 1

只需将quit <- true移动到第一个goroutine的末尾。

  1. func main() {
  2.     wg.Add(1)
  3.     st := []int{1, 2, 3, 4, 5, 6, 7, 8, 9, 10}
  4.     quit := make(chan bool)
  5.     ch := make(chan int)
  6.     go func() {
  7.         for i := range st {
  8.             ch <- i
  9.         }
  10.         quit <- true
  11.     }()
  13.     go func() {
  14.         for {
  15.             select {
  16.             case x := <-ch:
  17.                 fmt.Println(doSquare(x))
  18.                 // return
  20.             case <-quit:
  21.                 wg.Done()
  22.                 return
  23.             default:
  24.                 // fmt.Println("---")
  25.                 // do something
  26.             }
  27.         }
  28.     }()
  30.     wg.Wait()
  31. }

这是另一种通过close(ch)来表示没有更多数据的方法。

  1. func main() {
  2.     st := []int{1, 2, 3, 4, 5, 6, 7, 8, 9, 10}
  3.     quit := make(chan bool)
  4.     ch := make(chan int) // improve concurrency by `ch := make(chan int, 100)`
  5.     go func() {
  6.         for i := range st {
  7.             ch <- i
  8.         }
  9.         close(ch)
  10.     }()
  12.     go func() {
  13.         for x := range ch {
  14.             fmt.Println(doSquare(x))
  15.         }
  16.         quit <- true
  17.     }()
  19.     <-quit
  20. }
英文:

Just move quit &lt;- true to the end of the first goroutine

  1. func main() {
  2.     wg.Add(1)
  3.     st := []int{1, 2, 3, 4, 5, 6, 7, 8, 9, 10}
  4.     quit := make(chan bool)
  5.     ch := make(chan int)
  6.     go func() {
  7.         for i := range st {
  8.             ch &lt;- i
  9.         }
  10.         quit &lt;- true
  11.     }()
  13.     go func() {
  14.         for {
  15.             select {
  16.             case x := &lt;-ch:
  17.                 fmt.Println(doSquare(x))
  18.                 // return
  20.             case &lt;-quit:
  21.                 wg.Done()
  22.                 return
  23.             default:
  24.                 // fmt.Println(&quot;---&quot;)
  25.                 // do something
  26.             }
  27.         }
  28.     }()
  30.     wg.Wait()
  31. }

This is another way to signal there is no more data by close(ch)

  1. func main() {
  2.     st := []int{1, 2, 3, 4, 5, 6, 7, 8, 9, 10}
  3.     quit := make(chan bool)
  4.     ch := make(chan int) // improve concurrency by `ch := make(chan int, 100)`
  5.     go func() {
  6.         for i := range st {
  7.             ch &lt;- i
  8.         }
  9.         close(ch)
  10.     }()
  12.     go func() {
  13.         for x := range ch {
  14.             fmt.Println(doSquare(x))
  15.         }
  16.         quit &lt;- true
  17.     }()
  19.     &lt;-quit
  20. }

huangapple
  • 本文由 发表于 2023年4月27日 14:37:27
  • 转载请务必保留本文链接：https://go.coder-hub.com/76117415.html
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