Golang守护进程用法示例分析

pid = fork();
//pid > 0 父进程
//pid = 0 子进程
//pid < 0 出错

execve(pathname, argv, envp);
//pathname 可执行文件路径
//argv 参数列表
//envp 环境变量列表

//判 断当其是否是子进程，当父进程return之后，子进程会被 系统1 号进程接管
if os.Getppid() != 1 {
    // 将命令行参数中执行文件路径转换成可用路径
    filePath, _ := filepath.Abs(os.Args[0])
    cmd := exec.Command(filePath, os.Args[1:]...)
    // 将其他命令传入生成出的进程
    cmd.Stdin = os.Stdin // 给新进程设置文件描述符，可以重定向到文件中
    cmd.Stdout = os.Stdout
    cmd.Stderr = os.Stderr
    cmd.Start() // 开始执行新进程，不等待新进程退出
    os.Exit(0)
}

if os.Getppid()!=1{   
    args:=append([]string{filePath},os.Args[1:]...)
    os.StartProcess(filePath,args,&os.ProcAttr{Files:[]*os.File{os.Stdin,os.Stdout,os.Stderr}})
    os.Exit(0)
}

pid, _, sysErr := syscall.RawSyscall(syscall.SYS_FORK, 0, 0, 0)
if sysErr != 0 {
    Utils.LogErr(sysErr)
    os.Exit(0)
}

func main() {
    // ------------------------ 守护进程 start ------------------------
    basePath, _ := os.Getwd()
    baseDir := filepath.Dir(basePath)
    fmt.Println(fmt.Sprintf("basePath is %s and baseDir is %s", basePath, baseDir))
    // step1
    // 创建监听退出chan
    c := make(chan os.Signal)
    // 监听指定信号 ctrl+c kill
    signal.Notify(c, syscall.SIGHUP, syscall.SIGINT, syscall.SIGTERM, syscall.SIGQUIT)
    go func() {
        for s := range c {
            switch s {
            case syscall.SIGHUP, syscall.SIGINT, syscall.SIGTERM, syscall.SIGQUIT:
                utils.StopBusinessProcess(fmt.Sprintf("go_start | grep business"))
                os.Exit(0)
            default:
                fmt.Println("test stop others...")
            }
        }
    }()
    fmt.Println(fmt.Sprintf("os.args is %v", os.Args))
    join := strings.Join(os.Args, "")
    // step2
    if !strings.Contains(join, "-daemon") {
        fmt.Println("enter daemon branch...")
        isE, ierr := utils.CheckProRunning("go_start | grep daemon")
        if ierr != nil {
            fmt.Println("check daemon process failed, " + ierr.Error())
            return
        }
        if isE {
            fmt.Println("daemon process exist!")
        } else {
            fmt.Println("start daemon process...")
            // 启动守护进程
            cmd := exec.Command(os.Args[0], "-c", os.Args[2], "-d", os.Args[4], "-e", os.Args[6], "-daemon")
            cmd.Stdin = os.Stdin
            cmd.Stdout = os.Stdout
            cmd.Stderr = os.Stderr
            strerr := cmd.Start()
            if strerr != nil {
                fmt.Println("start daemon process fail," + strerr.Error())
                return
            }
            fmt.Println("start daemon process success!")
            time.Sleep(time.Second * 2)
            daePid := cmd.Process.Pid
            isDae, daeErr := utils.CheckProRunning("go_start | grep daemon")
            if daeErr != nil {
                fmt.Println("check daemon process failed, " + daeErr.Error())
                return
            }
            if isDae {
                fmt.Println(fmt.Sprintf("start daemon process success, pid is %d", daePid))
                return
            } else {
                fmt.Println("warning! start business process fail...")
            }
        }
    }
    // step3
    join = strings.Join(os.Args, "")
    if strings.Contains(join, "-daemon") {
        fmt.Println("enter business branch...")
        for {
            exist, checkerr := utils.CheckProRunning("go_start | grep business")
            if checkerr != nil {
                fmt.Println("check business failed, " + checkerr.Error())
                return
            }
            if exist {
                fmt.Println("business process exist!")
                time.Sleep(time.Second * 5)
                continue
            }
            fmt.Println("start business process...")
            command := exec.Command(fmt.Sprintf(fmt.Sprintf("%s/go_start", basePath), "-business", "-c", os.Args[2], "-d", os.Args[4], "-e", os.Args[6]))
            command.SysProcAttr = &syscall.SysProcAttr{Setpgid: true}
            if comerr := command.Start(); comerr != nil {
                fmt.Println("start business process failed, " + comerr.Error())
                return
            }
            time.Sleep(time.Second * 5)
            businessPid := command.Process.Pid
            exist, checkerr = utils.CheckProRunning("go_start | grep business")
            if checkerr != nil {
                fmt.Println("check business process failed, " + checkerr.Error())
                return
            }
            if exist {
                fmt.Println(fmt.Sprintf("start business process suceess, pid is %d", businessPid))
            } else {
                fmt.Println("warning! start business process fail...")
            }
        }
    }
    // ------------------------ 守护进程 end ------------------------
    // ------------------------ 业务进程 start ------------------------
    fmt.Println("hello, welcome to business detail!")
}

package utils
import (
    "os"
    "fmt"
    "go_start/core/global"
    "os/exec"
    "runtime"
    "strconv"
    "strings"
    "syscall"
)
func StopBusinessProcess(serverName string) {
    global.G_LOG.Info("start to stop business...")
    pid, _ := GetPid(serverName)
    if pid > 0 {
        global.G_LOG.Info(fmt.Sprintf("stop %s ...", serverName))
        syscall.Kill(pid, syscall.SIGKILL)
        global.G_LOG.Info(fmt.Sprintf("stop business success, pid is %d", pid))
    }
}
//根据进程名判断进程是否运行
func CheckProRunning(serverName string) (bool, error) {
    a := `ps -ef|grep ` + serverName + `|grep -v grep|awk '{print $2}'`
    pid, err := runCommand(a)
    if err != nil {
        return false, err
    }
    return pid != "", nil
}
//根据进程名称获取进程ID
func GetPid(serverName string) (pid int, err error) {
    a := `ps -ef|grep ` + serverName + `|grep -v grep|awk '{print $2}'`
    var pidStr string
    if pidStr, err = runCommand(a); err != nil {
        return
    }
    pid, err = strconv.Atoi(pidStr)
    return
}
func runCommand(cmd string) (string, error) {
    if runtime.GOOS == "windows" {
        return runInWindows(cmd)
    } else {
        return runInLinux(cmd)
    }
}
func runInWindows(cmd string) (string, error) {
    result, err := exec.Command("cmd", "/c", cmd).Output()
    if err != nil {
        return "", err
    }
    return strings.TrimSpace(string(result)), err
}
func runInLinux(cmd string) (string, error) {
    result, err := exec.Command("/bin/sh", "-c", cmd).Output()
    if err != nil {
        return "", err
    }
    return strings.TrimSpace(string(result)), err
}