{"id":207368,"date":"2025-07-08T11:54:24","date_gmt":"2025-07-08T03:54:24","guid":{"rendered":"https:\/\/server.hk\/cnblog\/207368\/"},"modified":"2025-07-08T11:54:24","modified_gmt":"2025-07-08T03:54:24","slug":"%e4%bd%bf%e7%94%a8-waitgroup-%e7%a8%8b%e5%ba%8f%e9%99%b7%e5%85%a5%e6%ad%bb%e9%94%81","status":"publish","type":"post","link":"https:\/\/server.hk\/cnblog\/207368\/","title":{"rendered":"\u4f7f\u7528 waitgroup \u7a0b\u5e8f\u9677\u5165\u6b7b\u9501"},"content":{"rendered":"

<\/b> <\/p>\n

\u5f53\u524d\u4f4d\u7f6e\uff1a ><\/span> ><\/span> ><\/span> ><\/span> \u4f7f\u7528 waitgroup \u7a0b\u5e8f\u9677\u5165\u6b7b\u9501<\/span><\/p>\n

\u6765\u6e90\uff1astackoverflow<\/span>
\n2024-04-21 23:18:36<\/span>
\n<\/i>0\u6d4f\u89c8<\/span>
\n<\/i>\u6536\u85cf<\/span> <\/p>\n

\u5b66\u4e60\u77e5\u8bc6\u8981\u5584\u4e8e\u601d\u8003\uff0c\u601d\u8003\uff0c\u518d\u601d\u8003\uff01\u4eca\u5929\u5c0f\u7f16\u5c31\u7ed9\u5927\u5bb6\u5e26\u6765\u300a\u4f7f\u7528 waitgroup \u7a0b\u5e8f\u9677\u5165\u6b7b\u9501\u300b<\/span>\uff0c\u4ee5\u4e0b\u5185\u5bb9\u4e3b\u8981\u5305\u542b<\/span>\u7b49\u77e5\u8bc6\u70b9\uff0c\u5982\u679c\u4f60\u6b63\u5728\u5b66\u4e60\u6216\u51c6\u5907\u5b66\u4e60Golang<\/span>\uff0c\u5c31\u90fd\u4e0d\u8981\u9519\u8fc7\u672c\u6587\u5566~\u8ba9\u6211\u4eec\u4e00\u8d77\u6765\u770b\u770b\u5427\uff0c\u80fd\u5e2e\u52a9\u5230\u4f60\u5c31\u66f4\u597d\u4e86\uff01<\/span><\/p>\n

\u95ee\u9898\u5185\u5bb9
\n <\/p>\n

\u6211\u6b63\u5728\u7f16\u5199\u4e00\u4e2a\u7a0b\u5e8f\uff0c\u8be5\u7a0b\u5e8f\u8bfb\u53d6\u540d\u4e3aorders.csv \u7684\u6587\u4ef6\u4e2d\u7684\u8ba2\u5355\u53f7\u5217\u8868\uff0c\u5e76\u5c06\u5176\u4e0e\u6587\u4ef6\u5939\u4e2d\u5b58\u5728\u7684\u5176\u4ed6 csv \u6587\u4ef6\u8fdb\u884c\u6bd4\u8f83\u3002<\/p>\n

\u95ee\u9898\u662f\uff0c\u5373\u4f7f\u4f7f\u7528 waitgroup\uff0c\u5b83\u4e5f\u4f1a\u9677\u5165\u6b7b\u9501\uff0c\u6211\u4e0d\u77e5\u9053\u4e3a\u4ec0\u4e48\u3002<\/p>\n

\u7531\u4e8e\u67d0\u79cd\u539f\u56e0\uff0cstackoverflow \u8bf4\u6211\u7684\u5e16\u5b50\u4e3b\u8981\u662f\u4ee3\u7801\uff0c\u6240\u4ee5\u6211\u5fc5\u987b\u6dfb\u52a0\u8fd9\u4e00\u884c\uff0c\u56e0\u4e3a\u5982\u679c\u6709\u4eba\u60f3\u5e2e\u52a9\u6211\u8c03\u8bd5\u6211\u9047\u5230\u7684\u8fd9\u4e2a\u95ee\u9898\uff0c\u6574\u4e2a\u4ee3\u7801\u662f\u5fc5\u8981\u7684\u3002<\/p>\n

package main\n\nimport (\n    \"bufio\"\n    \"fmt\"\n    \"log\"\n    \"os\"\n    \"path\/filepath\"\n    \"strings\"\n    \"sync\"\n)\n\ntype Files struct {\n    filenames []string\n}\n\ntype Orders struct {\n    ID []string\n}\n\nvar ordersFilename string = \"orders.csv\"\n\nfunc main() {\n    var (\n        ordersFile *os.File\n        files       Files\n        orders     Orders\n        err        error\n    )\n\n    mu := new(sync.Mutex)\n    wg := &sync.WaitGroup{}\n    wg.Add(1)\n\n    if ordersFile, err = os.Open(ordersFilename); err != nil {\n        log.Fatalln(\"Could not open file: \" + ordersFilename)\n    }\n\n    orders = getOrderIDs(ordersFile)\n\n    files.filenames = getCSVsFromCurrentDir()\n\n    var filenamesSize = len(files.filenames)\n    var ch = make(chan map[string][]string, filenamesSize)\n    var done = make(chan bool)\n\n    for i, filename := range files.filenames {\n        go func(currentFilename string, ch chan<- map[string][]string, i int, orders Orders, wg *sync.WaitGroup, filenamesSize *int, mu *sync.Mutex, done chan<- bool) {\n            wg.Add(1)\n            defer wg.Done()\n            checkFile(currentFilename, orders, ch)\n            mu.Lock()\n            *filenamesSize--\n            mu.Unlock()\n            if i == *filenamesSize {\n                done <- true\n                close(done)\n            }\n        }(filename, ch, i, orders, wg, &filenamesSize, mu, done)\n    }\n\n    select {\n    case str := <-ch:\n        fmt.Printf(\"%+v\\n\", str)\n    case <-done:\n        wg.Done()\n        break\n    }\n\n    wg.Wait()\n    close(ch)\n}\n\n\/\/ getCSVsFromCurrentDir returns a string slice\n\/\/ with the filenames of csv files inside the\n\/\/ current directory that are not \"orders.csv\"\nfunc getCSVsFromCurrentDir() []string {\n    var filenames []string\n\n    err := filepath.Walk(\".\", func(path string, info os.FileInfo, err error) error {\n        if path != \".\" && strings.HasSuffix(path, \".csv\") && path != ordersFilename {\n            filenames = append(filenames, path)\n        }\n\n        return nil\n    })\n\n    if err != nil {\n        log.Fatalln(\"Could not read file names in current dir\")\n    }\n\n    return filenames\n}\n\n\/\/ getOrderIDs returns an Orders struct filled\n\/\/ with order IDs retrieved from the file\nfunc getOrderIDs(file *os.File) Orders {\n    var (\n        orders      Orders\n        err         error\n        fileContent string\n    )\n\n    reader := bufio.NewReader(file)\n\n    if fileContent, err = readLine(reader); err != nil {\n        log.Fatalln(\"Could not read file: \" + ordersFilename)\n    }\n\n    for err == nil {\n        orders.ID = append(orders.ID, fileContent)\n        fileContent, err = readLine(reader)\n    }\n\n    return orders\n}\n\nfunc checkFile(filename string, orders Orders, ch chan<- map[string][]string) {\n    var (\n        err           error\n        file          *os.File\n        fileContent   string\n        orderFilesMap map[string][]string\n        counter       int\n    )\n\n    orderFilesMap = make(map[string][]string)\n\n    if file, err = os.Open(filename); err != nil {\n        log.Fatalln(\"Could not read file: \" + filename)\n    }\n\n    reader := bufio.NewReader(file)\n\n    if fileContent, err = readLine(reader); err != nil {\n        log.Fatalln(\"Could not read file: \" + filename)\n    }\n\n    for err == nil {\n        if containedInSlice(fileContent, orders.ID) && !containedInSlice(fileContent, orderFilesMap[filename]) {\n            orderFilesMap[filename] = append(orderFilesMap[filename], fileContent)\n            \/\/ fmt.Println(\"Found: \", fileContent, \" in \", filename)\n        } else {\n            \/\/ fmt.Printf(\"Could not find: '%s' in '%s'\\n\", fileContent, filename)\n        }\n        counter++\n        fileContent, err = readLine(reader)\n    }\n\n    ch <- orderFilesMap\n}\n\n\/\/ containedInSlice returns true or false\n\/\/ based on whether the string is contained\n\/\/ in the slice\nfunc containedInSlice(str string, slice []string) bool {\n    for _, ID := range slice {\n        if ID == str {\n            return true\n        }\n    }\n\n    return false\n}\n\n\/\/ readLine returns a line from the passed reader\nfunc readLine(r *bufio.Reader) (string, error) {\n    var (\n        isPrefix bool  = true\n        err      error = nil\n        line, ln []byte\n    )\n    for isPrefix && err == nil {\n        line, isPrefix, err = r.ReadLine()\n        ln = append(ln, line...)\n    }\n    return string(ln), err\n}<\/pre>\n
 <\/p>\n
\u89e3\u51b3\u65b9\u6848<\/h2>\n
 <\/p>\n
    \n
  1. \n
    \u7b2c\u4e00\u4e2a\u95ee\u9898\u662f wg.add<\/code> \u59cb\u7ec8\u5fc5\u987b\u4f4d\u4e8e\u5b83\u4ee3\u8868\u7684 goroutine \u4e4b\u5916\u3002\u5982\u679c\u4e0d\u662f\uff0c\u5219 wg.wait<\/code> \u8c03\u7528\u53ef\u80fd\u4f1a\u5728 goutine \u5b9e\u9645\u5f00\u59cb\u8fd0\u884c\u4e4b\u524d\u8c03\u7528\uff08\u5e76\u79f0\u4e3a wg.add<\/code>\uff09\uff0c\u56e0\u6b64\u4f1a\u201c\u601d\u8003\u201d \u6ca1\u6709\u4ec0\u4e48\u53ef\u4ee5\u7b49\u5f85\u7684\u3002<\/p>\n<\/li>\n
  2. \n
    \u4ee3\u7801\u7684\u7b2c\u4e8c\u4e2a\u95ee\u9898\u662f\u5b83\u6709\u591a\u79cd\u65b9\u5f0f\u7b49\u5f85\u4f8b\u7a0b\u5b8c\u6210\u3002\u6709 waitgroup<\/code> \u5e76\u4e14\u6709 done<\/code> \u901a\u9053\u3002\u4ec5\u4f7f\u7528\u5176\u4e2d\u4e4b\u4e00\u3002\u54ea\u4e00\u4e2a\u8fd8\u53d6\u51b3\u4e8e\u7ed3\u679c\u5982\u4f55 \u4f7f\u7528 goroutine\u3002\u6211\u4eec\u6765\u8ba8\u8bba\u4e0b\u4e00\u4e2a\u95ee\u9898\u3002<\/p>\n<\/li>\n
  3. \n
    \u7b2c\u4e09\u4e2a\u95ee\u9898\u662f\u6536\u96c6\u7ed3\u679c\u3002\u76ee\u524d\uff0c\u4ee3\u7801\u4ec5\u6253\u5370\/\u4f7f\u7528 goroutine \u7684\u5355\u4e2a\u7ed3\u679c\u3002 \u5728 select \u5468\u56f4\u653e\u7f6e\u4e00\u4e2a for { ... }<\/code> \u5faa\u73af\uff0c\u5e76\u5728 done<\/code> \u901a\u9053\u5173\u95ed\u65f6\u4f7f\u7528 return<\/code> \u8df3\u51fa\u5faa\u73af\u3002 \uff08\u8bf7\u6ce8\u610f\uff0c\u60a8\u4e0d\u9700\u8981\u5728 done<\/code> \u901a\u9053\u4e0a\u53d1\u9001\u4efb\u4f55\u5185\u5bb9\uff0c\u5173\u95ed\u5b83\u5c31\u8db3\u591f\u4e86\u3002\uff09<\/p>\n<\/li>\n<\/ol>\n
    \u6539\u8fdb\u7248\u672c0.0.1<\/h2>\n
    \u8fd9\u91cc\u662f\u7b2c\u4e00\u4e2a\u7248\u672c\uff08\u5305\u62ec\u5176\u4ed6\u4e00\u4e9b\u201c\u4ee3\u7801\u6e05\u7406\u201d\uff09\uff0c\u5176\u4e2d\u6709\u4e00\u4e2a\u7528\u4e8e\u5173\u95ed\u7684 done<\/code> \u901a\u9053\uff0c\u5e76\u5220\u9664\u4e86 waitgroup<\/code>\uff1a<\/p>\n
    func main() {\n    ordersfile, err := os.open(ordersfilename)\n    if err != nil {\n        log.fatalln(\"could not open file: \" + ordersfilename)\n    }\n\n    orders := getorderids(ordersfile)\n\n    files := files{\n        filenames: getcsvsfromcurrentdir(),\n    }\n\n    var (\n        mu = new(sync.mutex)\n        filenamessize = len(files.filenames)\n        ch = make(chan map[string][]string, filenamessize)\n        done = make(chan bool)\n    )\n\n    for i, filename := range files.filenames {\n        go func(currentfilename string, ch chan<- map[string][]string, i int, orders orders, filenamessize *int, mu *sync.mutex, done chan<- bool) {\n            checkfile(currentfilename, orders, ch)\n            mu.lock()\n            *filenamessize--\n            mu.unlock()\n            \/\/ todo: this also accesses filenamessize, so it also needs to be protected with the mutex:\n            if i == *filenamessize {\n                done <- true\n                close(done)\n            }\n        }(filename, ch, i, orders, &filenamessize, mu, done)\n    }\n\n    \/\/ note: closing a channel is not really needed, so you can omit this:\n    defer close(ch)\n    for {\n        select {\n        case str := <-ch:\n            fmt.printf(\"%+v\\n\", str)\n        case <-done:\n            return\n        }\n    }\n}\n<\/pre>\n
    \u6539\u8fdb\u7248\u672c0.0.2<\/h2>\n
      \n
    1. \u5bf9\u4e8e\u60a8\u7684\u60c5\u51b5\uff0c\u6211\u4eec\u6709\u4e00\u4e9b\u4f18\u52bf\u3002\u6211\u4eec\u786e\u5207\u5730\u77e5\u9053\u6211\u4eec\u542f\u52a8\u4e86\u591a\u5c11\u4e2a goroutine\uff0c\u56e0\u6b64\u4e5f\u77e5\u9053\u5982\u4f55\u542f\u52a8 \u6211\u4eec\u671f\u5f85\u8bb8\u591a\u7ed3\u679c\u3002 \uff08\u5f53\u7136\uff0c\u5982\u679c\u6bcf\u4e2a goroutine \u8fd4\u56de\u5f53\u524d\u4ee3\u7801\u6240\u505a\u7684\u7ed3\u679c\u3002\uff09\u8fd9\u7ed9\u51fa\u4e86 \u6211\u4eec\u8fd8\u6709\u53e6\u4e00\u79cd\u9009\u62e9\uff0c\u56e0\u4e3a\u6211\u4eec\u53ef\u4ee5\u4f7f\u7528\u53e6\u4e00\u4e2a\u5177\u6709\u76f8\u540c\u8fed\u4ee3\u6b21\u6570\u7684 for \u5faa\u73af\u6765\u6536\u96c6\u7ed3\u679c\uff1a<\/li>\n<\/ol>\n
      func main() {\n    ordersfile, err := os.open(ordersfilename)\n    if err != nil {\n        log.fatalln(\"could not open file: \" + ordersfilename)\n    }\n\n    orders := getorderids(ordersfile)\n\n    files := files{\n        filenames: getcsvsfromcurrentdir(),\n    }\n\n    var (\n        \/\/ note: a buffered channel helps speed things up. the size does not need to match the size of the items that will\n        \/\/   be passed through the channel. a fixed, small size is perfect here.\n        ch = make(chan map[string][]string, 5)\n    )\n\n    for _, filename := range files.filenames {\n        go func(filename string) {\n            \/\/ orders and channel are not variables of the loop and can be used without copying\n            checkfile(filename, orders, ch)\n        }(filename)\n    }\n\n    for range files.filenames {\n        str := <-ch\n        fmt.printf(\"%+v\\n\", str)\n    }\n}\n<\/pre>\n
      \u7b80\u5355\u591a\u4e86\uff0c\u4e0d\u662f\u5417\uff1f\u5e0c\u671b\u6709\u5e2e\u52a9\uff01<\/p>\n
      \u8fd9\u6bb5\u4ee3\u7801\u6709\u5f88\u591a\u9519\u8bef\u3002<\/p>\n
        \n
      1. \u60a8\u4f7f\u7528\u7684 waitgroup \u662f\u9519\u8bef\u7684\u3002 add \u5fc5\u987b\u5728\u4e3b goroutine \u4e2d\u8c03\u7528\uff0c\u5426\u5219\u6709\u53ef\u80fd\u5728\u6240\u6709 add \u8c03\u7528\u5b8c\u6210\u4e4b\u524d\u8c03\u7528 wait\u3002<\/li>\n
      2. \u521d\u59cb\u5316 waitgroup \u540e\u7acb\u5373\u8fdb\u884c\u4e86\u4e00\u4e2a\u65e0\u5173\u7684 add(1) \u8c03\u7528\uff0c\u8be5\u8c03\u7528\u4e0e done() \u8c03\u7528\u4e0d\u5339\u914d\uff0c\u56e0\u6b64 wait \u6c38\u8fdc\u4e0d\u4f1a\u8fd4\u56de\uff08\u5047\u8bbe\u4e0a\u9762\u7684\u70b9\u5df2\u4fee\u590d\uff09\u3002<\/li>\n
      3. \u60a8\u6b63\u5728\u4f7f\u7528 waitgroup \u548c done \u901a\u9053\u6765\u8868\u793a\u5b8c\u6210\u3002\u8fd9\u5145\u5176\u91cf\u662f\u591a\u4f59\u7684\u3002<\/li>\n
      4. \u60a8\u5728\u672a\u6301\u6709\u9501\u7684\u60c5\u51b5\u4e0b\u8bfb\u53d6 filenamessize\uff08\u5728 if i == *filenamessize<\/code> \u8bed\u53e5\u4e2d\uff09\u3002\u8fd9\u662f\u4e00\u4e2a\u7ade\u4e89\u6761\u4ef6\u3002<\/li>\n
      5. i == *filenamessize<\/code> \u6761\u4ef6\u9996\u5148\u6ca1\u6709\u4efb\u4f55\u610f\u4e49\u3002 goroutine \u4ee5\u4efb\u610f\u987a\u5e8f\u6267\u884c\uff0c\u56e0\u6b64\u4f60\u65e0\u6cd5\u786e\u5b9a i == 0 \u7684 goroutine \u662f\u6700\u540e\u4e00\u4e2a\u51cf\u5c11 filenamessize \u7684 goroutine<\/li>\n<\/ol>\n
        \u8fd9\u4e00\u5207\u90fd\u53ef\u4ee5\u901a\u8fc7\u6446\u8131\u5927\u90e8\u5206 if \u540c\u6b65\u539f\u8bed\u5e76\u5728\u6240\u6709 goroutine \u5b8c\u6210\u65f6\u7b80\u5355\u5730\u5173\u95ed ch \u901a\u9053\u6765\u7b80\u5316\uff1a<\/p>\n
        func main() { \n    ch := make(chan map[string][]string)\n    var wg WaitGroup\n\n    for _, filename := range getCSVsFromCurrentDir() { \n        filename := filename \/\/ capture loop var\n        wg.Add(1)\n        go func() { \n            checkFile(filename, orders, ch)\n            wg.Done()\n        }()\n    } \n\n    go func() { \n        wg.Wait() \/\/ after all goroutines are done...\n        close(ch) \/\/ let range loop below exit\n    }()\n\n    for str := range ch { \n        \/\/ ...\n    } \n}\n<\/pre>\n
        \u5230\u8fd9\u91cc\uff0c\u6211\u4eec\u4e5f\u5c31\u8bb2\u5b8c\u4e86\u300a\u4f7f\u7528 waitgroup \u7a0b\u5e8f\u9677\u5165\u6b7b\u9501\u300b\u7684\u5185\u5bb9\u4e86\u3002\u4e2a\u4eba\u8ba4\u4e3a\uff0c\u57fa\u7840\u77e5\u8bc6\u7684\u5b66\u4e60\u548c\u5de9\u56fa\uff0c\u662f\u4e3a\u4e86\u66f4\u597d\u7684\u5c06\u5176\u8fd0\u7528\u5230\u9879\u76ee\u4e2d\uff0c\u6b22\u8fce\u5173\u6ce8\u516c\u4f17\u53f7\uff0c\u5e26\u4f60\u4e86\u89e3\u66f4\u591a\u5173\u4e8e\u7684\u77e5\u8bc6\u70b9\uff01<\/p>\n","protected":false},"excerpt":{"rendered":"
        \u5f53\u524d\u4f4d\u7f6e\uff1a > > ...<\/p>\n","protected":false},"author":1,"featured_media":0,"comment_status":"closed","ping_status":"","sticky":false,"template":"","format":"standard","meta":{"footnotes":""},"categories":[4925],"tags":[],"class_list":["post-207368","post","type-post","status-publish","format-standard","hentry","category-4925"],"_links":{"self":[{"href":"https:\/\/server.hk\/cnblog\/wp-json\/wp\/v2\/posts\/207368","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/server.hk\/cnblog\/wp-json\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/server.hk\/cnblog\/wp-json\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/server.hk\/cnblog\/wp-json\/wp\/v2\/users\/1"}],"replies":[{"embeddable":true,"href":"https:\/\/server.hk\/cnblog\/wp-json\/wp\/v2\/comments?post=207368"}],"version-history":[{"count":0,"href":"https:\/\/server.hk\/cnblog\/wp-json\/wp\/v2\/posts\/207368\/revisions"}],"wp:attachment":[{"href":"https:\/\/server.hk\/cnblog\/wp-json\/wp\/v2\/media?parent=207368"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/server.hk\/cnblog\/wp-json\/wp\/v2\/categories?post=207368"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/server.hk\/cnblog\/wp-json\/wp\/v2\/tags?post=207368"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}