package runner import ( "fmt" "io/ioutil" "os" "os/exec" "path/filepath" "strconv" "strings" "time" "git.rootprojects.org/root/serviceman/service" ps "github.com/mitchellh/go-ps" ) // Filled in on init by runner_windows.go var shellArgs = []string{} // Notes on spawning a child process // https://groups.google.com/forum/#!topic/golang-nuts/shST-SDqIp4 // Start will execute the service, and write the PID and logs out to the log directory func Start(conf *service.Service) error { pid := os.Getpid() originalBackoff := 1 * time.Second maxBackoff := 1 * time.Minute threshold := 5 * time.Second backoff := originalBackoff failures := 0 logfile := filepath.Join(conf.Logdir, conf.Name+".log") if oldPid, exename, err := getProcess(conf); nil == err { return fmt.Errorf("%q may already be running as %q (pid %d)", conf.Name, exename, oldPid) } go func() { for { maybeWritePidFile(pid, conf) time.Sleep(1 * time.Second) } }() binpath := conf.Exec args := []string{} if "" != conf.Interpreter { binpath = conf.Interpreter args = append(args, conf.Exec) } args = append(args, conf.Argv...) if !conf.System && 0 != len(shellArgs) { nargs := append(shellArgs[1:], binpath) args = append(nargs, args...) binpath = shellArgs[0] } for { // setup the log lf, err := os.OpenFile(logfile, os.O_WRONLY|os.O_CREATE|os.O_APPEND, 0644) if nil != err { fmt.Fprintf(os.Stderr, "[%s] Could not open log file %q\n", time.Now(), logfile) lf = os.Stderr } else { defer lf.Close() } start := time.Now() cmd := exec.Command(binpath, args...) backgroundCmd(cmd) fmt.Fprintf(lf, "[%s] Starting %q %s \n", time.Now(), binpath, strings.Join(args, " ")) cmd.Stdin = nil cmd.Stdout = lf cmd.Stderr = lf if "" != conf.Workdir { cmd.Dir = conf.Workdir } if len(conf.Envs) > 0 { for k, v := range conf.Envs { cmd.Env = append(cmd.Env, k+"="+v) } } err = cmd.Start() if nil != err { fmt.Fprintf(lf, "[%s] Could not start %q process: %s\n", time.Now(), conf.Name, err) } else { err = cmd.Wait() if nil != err { fmt.Fprintf(lf, "[%s] Process %q failed with error: %s\n", time.Now(), conf.Name, err) } else { fmt.Fprintf(lf, "[%s] Process %q exited cleanly\n", time.Now(), conf.Name) } } // if this is a oneshot... so it is if !conf.Restart { fmt.Fprintf(lf, "Not restarting %q because `restart` set to `false`\n", conf.Name) break } end := time.Now() if end.Sub(start) > threshold { backoff = originalBackoff failures = 0 } else { failures++ fmt.Fprintf(lf, "Waiting %s to restart %q (%d consequtive immediate exits)\n", backoff, conf.Name, failures) time.Sleep(backoff) backoff *= 2 if backoff > maxBackoff { backoff = maxBackoff } } } return nil } // Stop will find and stop another serviceman runner instance by it's PID func Stop(conf *service.Service) error { i := 0 var err error for { if i >= 3 { return err } i++ oldPid, exename, err2 := getProcess(conf) err = err2 switch err { case nil: fmt.Printf("killing old process %q with pid %d\n", exename, oldPid) err := kill(oldPid) if nil != err { return err } return waitForProcessToDie(oldPid) case ErrNoPidFile: return err case ErrNoProcess: return err case ErrInvalidPidFile: fallthrough default: // waiting a little bit since the PID is written every second time.Sleep(400 * time.Millisecond) } } return fmt.Errorf("unexpected error: %s", err) } // Restart calls Stop, ignoring any failure, and then Start, returning any failure func Restart(conf *service.Service) error { _ = Stop(conf) return Start(conf) } var ErrNoPidFile = fmt.Errorf("no pid file") var ErrInvalidPidFile = fmt.Errorf("malformed pid file") var ErrNoProcess = fmt.Errorf("process not found by pid") func waitForProcessToDie(pid int) error { exename := "unknown" for i := 0; i < 10; i++ { px, err := ps.FindProcess(pid) if nil != err { return nil } if nil == px { return nil } exename = px.Executable() time.Sleep(1 * time.Second) } return fmt.Errorf("process %q (%d) just won't die", exename, pid) } func getProcess(conf *service.Service) (int, string, error) { // TODO make Pidfile() a property of conf? pidFile := filepath.Join(conf.Logdir, conf.Name+".pid") b, err := ioutil.ReadFile(pidFile) if nil != err { return 0, "", ErrNoPidFile } s := strings.TrimSpace(string(b)) oldPid, err := strconv.Atoi(s) if nil != err { return 0, "", ErrInvalidPidFile } px, err := ps.FindProcess(oldPid) if nil != err { return 0, "", err } if nil == px { return 0, "", ErrNoProcess } _, err = os.FindProcess(oldPid) if nil != err { return 0, "", err } exename := px.Executable() return oldPid, exename, nil } // TODO error out if can't write to PID or log func maybeWritePidFile(pid int, conf *service.Service) bool { newPid := []byte(strconv.Itoa(pid)) // TODO use a specific PID dir? meh... pidFile := filepath.Join(conf.Logdir, conf.Name+".pid") b, err := ioutil.ReadFile(pidFile) if nil != err { ioutil.WriteFile(pidFile, newPid, 0644) return true } s := strings.TrimSpace(string(b)) oldPid, err := strconv.Atoi(s) if nil != err { ioutil.WriteFile(pidFile, newPid, 0644) return true } if oldPid != pid { Stop(conf) ioutil.WriteFile(pidFile, newPid, 0644) return true } return false }