优雅退出

并发读3个文件-开3个线程-插入管道-开1个线程写入新文件后优雅退出

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package main
 
import (
    "bufio"
    "fmt"
    "io"
    "io/ioutil"
    "os"
    "path/filepath"
    "runtime"
    "strings"
    "sync"
)
 
var ch = make(chan string, 1000000) //  读文件插入的隧道
var write_main = make(chan struct{}) // 优雅退出main协程的空隧道
var wg_1 = sync.WaitGroup{} //优先等待读文件协程全部结束后 在执行下一步操作
<br>//读目录下所有txt文件获取path+文件名
func FileName(path string) (string, []string) {
    filename := []string{}
    subDirs, err := ioutil.ReadDir(path)
    // fmt.Println(subDirs)
    if err != nil {
        return "nil", nil
    }
    for _, dir := range subDirs {
        if dir.IsDir() {
            FileName(filepath.Join(path, dir.Name()))
        } else {
            if strings.HasSuffix(dir.Name(), ".txt") {
                // fmt.Println(dir.Name())
                filename = append(filename, dir.Name())
            }
        }
    }
    return path, filename
}<br><br>3个协程并发读文件
func ReadFile(path string, filename []string) {
    wg_1.Add(len(filename))
 
    for _, v := range filename {
 
        go func(v string) {
            //读文件并发
            path_filename := path + "/" + v
 
            fin, err := os.Open(path_filename)
            if err != nil {
                fmt.Printf("打开文件失败:%v\n", err)
            }
            defer fin.Close()
 
            reder := bufio.NewReader(fin)
            // Hostslice := []string{}
 
            for {
                line, err := reder.ReadString('\n')
                fmt.Println(line, "line")
                if err != nil {
                    if err == io.EOF {
                        break
                    } else {
                        fmt.Printf("读文件失败:%v\n", err)
                    }
                } else {
                    line = strings.TrimRight(line, "\n")
                    ch <- line
                    fmt.Println(line, "插入管道的每一行")
                }
            }
            wg_1.Done()
        }(v)
    }
 
}
func WriteFile(ch chan string) {
    f, err := os.OpenFile("dir/new.txt", os.O_CREATE|os.O_APPEND|os.O_WRONLY, 0777)
    if err != nil {
        fmt.Println("打开文件失败", err)
    }
    defer f.Close()
    for {
        v, ok := <-ch
        if !ok {
            break
        } else {
            writer := bufio.NewWriter(f)
            writer.WriteString(v + "\n")
            writer.Flush()
            fmt.Println(v, "write")
        }
    }
    <-write_main
}
 
func main() {
    path, filename := FileName("dir") 
    ReadFile(path, filename)
    fmt.Println("当前存在的协程数量", runtime.NumGoroutine())
    go WriteFile(ch)
    wg_1.Wait()              //等读完文件
    close(ch)                //读完关闭文件
    write_main <- struct{}{} //先插入一条进管道，然后write执行后取出管道
    fmt.Println("当前存在的协程数量", runtime.NumGoroutine())
 
}