所以我在 golang 中创建了一些日志分析器，我需要的是新创建文件的实时 tail -f。

我正在使用 tail 包和 fsnotify 包，但我不太熟悉 go 中的 channel 和例程，所以我需要一些帮助。

目前程序是这样的:

package main

import(
    "fmt"
    "github.com/hpcloud/tail"
    "strings"
    "log"
    "net/smtp"
    "time"
    "github.com/fsnotify/fsnotify"
)

//this function needs to monitor for new files in directory
func newFileCheck() (newFilename chan string, err error) {
    watcher, err := fsnotify.NewWatcher()
    if err != nil {
        return
    }

    err = watcher.Add("myDir")
    if err != nil {
        return
    }

    newFilename = make(chan string)

    // Process events
    go func() {
        for {
            select {
            case ev := <-watcher.Events:
                log.Println("event:", ev)
                newFilename <- ev.Name // Relative path to the file
                //t.Stop() //if I pass reference to t THIS IS NOT HAPPENING ?
            case err := <-watcher.Errors:
                log.Println("error:", err)
            }
        }
    }()

    return
}

func main() {
    newFileName = "mylog_0000.log.txt"

    fmt.Println("Processing log: ",newFileName)

    newFilenameChan, err := newFileCheck()
    if err != nil {
        fmt.Println("ERR: ",err)
    }

    t := tailLog(newFileName)

    go func() {
        for {
            select {
                case name := <-newFilenameChan:
                    fmt.Println("New file created: ",name) //this will be printed only once and then on new events nothing is printed ?

                //NONE of the lines abowe doesn't work
                t.Stop()
                t.Dead()
                t.Done()

                t = tailLog(name)
            }
        }
    }()
}

func tailLog(fileName string) *tail.Tail{
    var count = 0
    // close the old one and read new file
    t, err := tail.TailFile("/mydir/"+fileName, tail.Config{Follow: true, ReOpen: true})

    for line := range t.Lines {
        //fmt.Println("Line is:", line.Text)

        //check do we have what we need
        if strings.Contains(strings.ToLower(line.Text), "mfc"){

            count++
            //do other stuff
        }
    }

    fmt.Println(err)

    return t
}

所以我不明白为什么 newFileCheck 函数只在第一次打印事件，而且我也不知道如何在新事件发生时取消事件尾部，然后在该事件发生后再次开始尾部？

最佳答案

考虑一下:

When the function main returns, the program exits. It does not wait for other (non-main) goroutines to complete.

然后查看您的代码块:

func main() {
    newFileName = "mylog_0000.log.txt"

    fmt.Println("Processing log: ",newFileName)

    newFilenameChan, err := newFileCheck()
    if err != nil {
        fmt.Println("ERR: ",err)
    }

    t := tailLog(newFileName)

    go func() {
        for {
            select {
                case name := <-newFilenameChan:
                    fmt.Println("New file created: ",name) //this will be printed only once and then on new events nothing is printed ?

                //NONE of the lines abowe doesn't work
                t.Stop()
                t.Dead()
                t.Done()

                t = tailLog(name)
            }
        }
    }()
}

要优雅地处理这项工作，您应该了解更多关于 Golang 中的并发性。如果您对执行/完成任务的顺序感兴趣，请使用 channel 来控制 goroutine，例如停止/启动/等和 WaitGroup。当无法控制您的程序流程时，goroutines 可以过自己的生活，这是不好的做法。

关于go - 中断当前的尾部并开始新的尾部，我们在Stack Overflow上找到一个类似的问题： https://stackoverflow.com/questions/41243206/