转到lang多等待组，计时器最后停止

Question

i have written the following code in order to run until someone exit the program manually.

it does is

• ----- check if the exists every 1 second

• ----- if available then read the file and print the file content line by line

for this i have first call a function from the main and then i call a waitgroup and call a function again from there to do the aforementioned tasks.

please check if i have written the source code correctly as im a newbi on GO

plus this only runs once and stop... i want to it keep alive and see if the file exsists

please help me

 package main

import (
    "encoding/csv"
    "fmt"
    "io"
    "log"
    "os"
    "sync"
    "time"
)

func main() {
    mainfunction()
}

//------------------------------------------------------------------

func mainfunction() {
    var wg sync.WaitGroup
    wg.Add(1)

    go filecheck(&wg)

    wg.Wait()
    fmt.Printf("Program finished 
")

}

func filecheck(wg *sync.WaitGroup) {

    for range time.Tick(time.Second * 1) {
        fmt.Println("Foo")

        var wgi sync.WaitGroup
        wgi.Add(1)

        oldName := "test.csv"
        newName := "testi.csv"

        if _, err := os.Stat(oldName); os.IsNotExist(err) {
            fmt.Printf("Path does not exsist 
")
        } else {
            os.Rename(oldName, newName)
            if err != nil {
                log.Fatal(err)
            }
            looping(newName, &wgi)
        }
        fmt.Printf("Test complete 
")
        wgi.Wait()
        wg.Done()
        time.Sleep(time.Second * 5)
    }
}

func looping(newName string, wgi *sync.WaitGroup) {
    file, _ := os.Open(newName)
    r := csv.NewReader(file)
    for {
        record, err := r.Read()
        if err == io.EOF {
            break
        }
        if err != nil {
            log.Fatal(err)
        }

        var Date = record[0]
        var Agent = record[1]
        var Srcip = record[2]
        var Level = record[3]

        fmt.Printf("Data: %s Agent: %s Srcip: %s Level: %s
", Date, Agent, Srcip, Level)
    }
    fmt.Printf("Test complete 2 
")
    wgi.Done()

    fmt.Printf("for ended")
}

Answer 1

The short answer is that you have this in the loop:

    wg.Done()

Which makes the main goroutine proceed to exit as soon as the file is read once.

---

The longer answer is that you're not using wait groups correctly here, IMHO. For example there's absolutely no point in passing a WaitGroup into looping.

It's not clear what your code is trying to accomplish - you certainly don't need any goroutines to just perform the task you've specified - it can all be gone with no concurrency and thus simpler code.