有没有更好的方法来跟踪goroutine的响应？

huangapple
go评论122阅读模式
英文:

Any better way to keep track of goroutine responses?

问题

我正在努力理解goroutines。我创建了一个简单的程序，可以在多个搜索引擎上并行执行相同的搜索。目前，为了跟踪响应的数量，我计算了我收到的响应数量。但这似乎有点业余。

在下面的代码中，有没有更好的方法来知道我是否收到了所有goroutines的响应？

  1. package main
  3. import (
  4. 	"fmt"
  5. 	"net/http"
  6. 	"log"
  7. )
  9. type Query struct {
  10. 	url    string
  11. 	status string
  12. }
  14. func search(url string, out chan Query) {
  15. 	fmt.Printf("Fetching URL %s\n", url)
  16. 	resp, err := http.Get(url)
  18. 	if err != nil {
  19. 		log.Fatal(err)
  20. 	}
  22. 	defer resp.Body.Close()
  24. 	out <- Query{url, resp.Status}
  25. }
  27. func main() {
  28. 	searchTerm := "carrot"
  30. 	fmt.Println("Hello world! Searching for ", searchTerm)
  32. 	searchEngines := []string{
  33. 		"http://www.bing.co.uk/?q=",
  34. 		"http://www.google.co.uk/?q=",
  35. 		"http://www.yahoo.co.uk/?q="}
  37. 	out := make(chan Query)
  39. 	for i := 0; i < len(searchEngines); i++ {
  40. 		go search(searchEngines[i]+searchTerm, out)
  41. 	}
  43. 	progress := 0
  45. 	for {
  46. 		// 有没有更好的方法来执行这一步？
  47. 		if progress >= len(searchEngines) {
  48. 			break
  49. 		}
  50. 		fmt.Println("Polling...")
  51. 		query := <-out
  52. 		fmt.Printf("Status from %s was %s\n", query.url, query.status)
  53. 		progress++
  54. 	}
  55. }
英文:

I'm trying to get my head around goroutines. I've created a simple program that performs the same search in parallel across multiple search engines. At the moment to keep track of the number of responses, I count the number I've received. It seems a bit amateur though.

Is there a better way of knowing when I've received a response from all of the goroutines in the following code?

  1. package main
  3. import (
  4. 	&quot;fmt&quot;
  5. 	&quot;net/http&quot;
  6. 	&quot;log&quot;
  7. )
  9. type Query struct {
  10. 	url string
  11. 	status string
  12. }
  14. func search (url string, out chan Query) {
  15. 	fmt.Printf(&quot;Fetching URL %s\n&quot;, url)
  16. 	resp, err := http.Get(url)
  18. 	if err != nil {
  19. 		log.Fatal(err)
  20. 	}
  22. 	defer resp.Body.Close()
  24. 	out &lt;- Query{url, resp.Status}
  25. }
  27. func main() {
  28. 	searchTerm := &quot;carrot&quot;
  30. 	fmt.Println(&quot;Hello world! Searching for &quot;, searchTerm)
  32. 	searchEngines := []string{
  33. 		&quot;http://www.bing.co.uk/?q=&quot;,
  34. 		&quot;http://www.google.co.uk/?q=&quot;,
  35. 		&quot;http://www.yahoo.co.uk/?q=&quot;}
  37. 	out := make(chan Query)
  39. 	for i := 0; i &lt; len(searchEngines); i++ {
  40. 		go search(searchEngines[i] + searchTerm, out)
  41. 	}
  43. 	progress := 0
  45. 	for {
  46.                     // is there a better way of doing this step?
  47. 		if progress &gt;= len(searchEngines) {
  48. 			break
  49. 		}
  50. 		fmt.Println(&quot;Polling...&quot;)
  51. 		query := &lt;-out
  52. 		fmt.Printf(&quot;Status from %s was %s\n&quot;, query.url, query.status)
  53. 		progress++
  54. 	}
  55. }

答案1

得分: 12

请使用sync.WaitGroup，在pkg doc中有一个示例

  1. searchEngines := []string{
  2. 	"http://www.bing.co.uk/?q=",
  3. 	"http://www.google.co.uk/?q=",
  4. 	"http://www.yahoo.co.uk/?q="}
  5. var wg sync.WaitGroup
  6. out := make(chan Query)
  8. for i := 0; i < len(searchEngines); i++ {
  9.     wg.Add(1)
  10. 	go func (url string) {
  11.         defer wg.Done()
  12. 		fmt.Printf("Fetching URL %s\n", url)
  13. 		resp, err := http.Get(url)
  15. 		if err != nil {
  16. 			log.Fatal(err)
  17. 		}
  19. 		defer resp.Body.Close()
  21. 		out <- Query{url, resp.Status}
  22. 		
  23. 	}(searchEngines[i] + searchTerm)
  24. 	
  25. }
  26. wg.Wait()
英文:

Please use sync.WaitGroup, there is an example in the pkg doc

  1. searchEngines := []string{
  2. 	&quot;http://www.bing.co.uk/?q=&quot;,
  3. 	&quot;http://www.google.co.uk/?q=&quot;,
  4. 	&quot;http://www.yahoo.co.uk/?q=&quot;}
  5. var wg sync.WaitGroup
  6. out := make(chan Query)
  8. for i := 0; i &lt; len(searchEngines); i++ {
  9.     wg.Add(1)
  10. 	go func (url string) {
  11.         defer wg.Done()
  12. 		fmt.Printf(&quot;Fetching URL %s\n&quot;, url)
  13. 		resp, err := http.Get(url)
  15. 		if err != nil {
  16. 			log.Fatal(err)
  17. 		}
  19. 		defer resp.Body.Close()
  21. 		out &lt;- Query{url, resp.Status}
  22. 		
  23. 	}(searchEngines[i] + searchTerm)
  24. 	
  25. }
  26. wg.Wait()

huangapple
  • 本文由 发表于 2013年2月23日 17:00:27
  • 转载请务必保留本文链接：https://go.coder-hub.com/15038834.html
  • go
  • goroutine
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