Use nmz to inspect process deployed by tidb-ansible.

proc_inspect.go

package main

import (
    "context"
    "flag"
    "fmt"
    "io/ioutil"
    "os"
    "os/exec"
    "strconv"
    "strings"
    "syscall"
    "time"
)

var (
    pidFile       = flag.String("pid-file", "", "PID file to get real PID")
    nmzConfigFile = flag.String("nmz", "", "namazu config file")
)

func readPID() (int64, error) {
    data, err := ioutil.ReadFile(*pidFile)
    if err != nil {
        return 0, err
    }

    pid, err := strconv.ParseInt(strings.TrimSpace(string(data)), 10, 64)
    if err != nil {
        return 0, err
    }

    return pid, nil
}

func pexit(msg string) {
    println(msg)
    os.Exit(1)
}

func checkProcExist(pid int64) error {
    process, err := os.FindProcess(int(pid))
    if err != nil {
        return err
    }

    if err = process.Signal(syscall.Signal(0)); err != nil {
        return err
    }

    return nil
}

func runInspect(pid int64) {
    ctx, cancel := context.WithCancel(context.Background())

    go func() {
        defer cancel()

        t := time.NewTicker(time.Second)
        defer t.Stop()
        for {
            <-t.C

            if err := checkProcExist(pid); err != nil {
                fmt.Printf("check process %d failed, err %v", pid, err)
                return
            }
        }
    }()

    cmd := exec.CommandContext(ctx, "nmz", "inspectors", "proc", "-pid",
        strconv.FormatInt(pid, 10), "-autopilot",
        *nmzConfigFile, "-watch-interval", "1s")
    cmd.Stdout = os.Stdout
    cmd.Stderr = os.Stderr
    cmd.Run()
}

func main() {
    flag.Parse()

    if len(*pidFile) == 0 {
        pexit("must assign the PID file")
    }

    if len(*nmzConfigFile) == 0 {
        pexit("must assign the namazu config file")
    }

    for {
        pid, err := readPID()
        if err != nil {
            fmt.Printf("can't read PID from PID file %s, retry later", *pidFile)
            time.Sleep(5 * time.Second)
            continue
        }

        if err := checkProcExist(pid); err != nil {
            fmt.Printf("check process %d failed, err %v, retry later", pid, err)
            time.Sleep(5 * time.Second)
            continue
        }

        runInspect(pid)
    }
}