[英]Why is my Golang Channel Write Blocking Forever?
在過去的幾天里,我一直試圖通過重構我的一個命令行實用程序來解決Golang的並發問題,但我陷入了困境。
這是原始代碼(主分支)。
這是具有並發性的分支(x_concurrent分支)。
當我使用go run jira_open_comment_emailer.go
執行並發代碼時,如果將JIRA問題添加到此處的通道,則defer wg.Done()
永遠不會執行,這會導致我的wg.Wait()
永遠掛起。
這個想法是我有大量的JIRA問題,我想為每個問題分拆一個goroutine,看看它是否有我需要回應的評論。 如果是這樣,我想將它添加到某個結構(我在一些研究后選擇了一個頻道),我可以稍后從隊列中讀取以構建電子郵件提醒。
這是代碼的相關部分:
// Given an issue, determine if it has an open comment
// Returns true if there is an open comment on the issue, otherwise false
func getAndProcessComments(issue Issue, channel chan<- Issue, wg *sync.WaitGroup) {
// Decrement the wait counter when the function returns
defer wg.Done()
needsReply := false
// Loop over the comments in the issue
for _, comment := range issue.Fields.Comment.Comments {
commentMatched, err := regexp.MatchString("~"+config.JIRAUsername, comment.Body)
checkError("Failed to regex match against comment body", err)
if commentMatched {
needsReply = true
}
if comment.Author.Name == config.JIRAUsername {
needsReply = false
}
}
// Only add the issue to the channel if it needs a reply
if needsReply == true {
// This never allows the defered wg.Done() to execute?
channel <- issue
}
}
func main() {
start := time.Now()
// This retrieves all issues in a search from JIRA
allIssues := getFullIssueList()
// Initialize a wait group
var wg sync.WaitGroup
// Set the number of waits to the number of issues to process
wg.Add(len(allIssues))
// Create a channel to store issues that need a reply
channel := make(chan Issue)
for _, issue := range allIssues {
go getAndProcessComments(issue, channel, &wg)
}
// Block until all of my goroutines have processed their issues.
wg.Wait()
// Only send an email if the channel has one or more issues
if len(channel) > 0 {
sendEmail(channel)
}
fmt.Printf("Script ran in %s", time.Since(start))
}
goroutines阻止發送到無緩沖的通道。 解決goroutines的最小變化是創建一個緩沖通道,其容量適用於所有問題:
channel := make(chan Issue, len(allIssues))
並在調用wg.Wait()后關閉通道。
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