Golang Cmd.Start方法代码示例

func (w *Worker) ExecBin(binPath string, args []string, maxRunTime int64) (string, error) {
	var cmd *exec.Cmd
	var stdout bytes.Buffer
	var stderr bytes.Buffer
	var err error

	if len(args) == 0 {
		cmd = exec.Command(binPath)
	} else {
		cmd = exec.Command(binPath, args...)
	}

	cmd.Stdout = &stdout
	cmd.Stderr = &stderr
	cmd.Start() // attention!

	err, _ = w.CmdRunWithTimeout(cmd,
		time.Duration(maxRunTime)*time.Second,
	)
	if err != nil {
		return "", err
	}
	if len(stderr.String()) != 0 {
		errMsg := strings.TrimRight(stderr.String(), "\n")
		return "", errors.NewError(errMsg)
	}

	return strings.TrimRight(stdout.String(), "\n"), nil
}

func source(dir, from, to string) <-chan string {
	var cmd *exec.Cmd
	if to == "" {
		cmd = exec.Command("git", "-C", dir, "log", `--pretty=format:hash: %H%n-----%nauthor: %an <%ae>%n-----%nrawSubject: %s%n-----%nrawBody: %b%n-----%nEND-COMMIT%n`, from)
	} else {
		cmd = exec.Command("git", "-C", dir, "log", `--pretty=format:hash: %H%n-----%nauthor: %an <%ae>%n-----%nrawSubject: %s%n-----%nrawBody: %b%n-----%nEND-COMMIT%n`, to+".."+from)
	}

	outputChannel := make(chan string)

	output, err := cmd.StdoutPipe()
	if err != nil {
		panic(err)
	}
	err = cmd.Start()
	if err != nil {
		log.Fatal(err)
	}

	go func() {
		scanner := bufio.NewScanner(output)
		for scanner.Scan() {
			outputChannel <- scanner.Text()
		}
		defer output.Close()
		close(outputChannel)
		if err := scanner.Err(); err != nil {
			log.Fatal(err)
		}
	}()
	return outputChannel
}

func execCommand(cmd *exec.Cmd) error {
	cmdReader, err := cmd.StdoutPipe()
	if err != nil {
		fmt.Fprintln(os.Stderr, "Error creating StdoutPipe for Cmd", err)
		return err
	}

	scanner := bufio.NewScanner(cmdReader)
	go func() {
		for scanner.Scan() {
			fmt.Printf("docker build out | %s\n", scanner.Text())
		}
	}()

	var stderr bytes.Buffer
	cmd.Stdout = os.Stdout
	cmd.Stderr = &stderr

	err = cmd.Start()
	if err != nil {
		fmt.Printf("docker build out | %s\n", stderr.String())
		return err
	}

	err = cmd.Wait()
	if err != nil {
		fmt.Printf("docker build out | %s\n", stderr.String())
		return err
	}
	return err
}

// send produces a binary diff stream and passes it to cont
func send(repo, commit string, cont func(io.Reader) error) error {
	parent := GetMeta(path.Join(repo, commit), "parent")
	var cmd *exec.Cmd
	if parent == "" {
		cmd = exec.Command("btrfs", "send", FilePath(path.Join(repo, commit)))
	} else {
		cmd = exec.Command("btrfs", "send", "-p", FilePath(path.Join(repo, parent)), FilePath(path.Join(repo, commit)))
	}
	stdin, stdout := io.Pipe()
	stderr := bytes.NewBuffer(nil)
	cmd.Stdout = stdout
	if err := cmd.Start(); err != nil {
		return err
	}
	errC := make(chan error, 1)
	go func() {
		errC <- cont(stdin)
	}()
	waitErr := cmd.Wait()
	closeErr := stdout.Close()
	if waitErr != nil {
		return fmt.Errorf("%s %s", waitErr.Error(), stderr.String())
	}
	if closeErr != nil {
		return closeErr
	}
	return <-errC
}

func (this *Start) reloadHAproxy() (err error) {
	var cmd *exec.Cmd = nil
	waitStartCh := make(chan struct{})
	if this.starting {
		log.Info("haproxy starting")
		cmd = exec.Command(this.command, "-f", configFile) // TODO use absolute path
		this.starting = false

		go func() {
			<-waitStartCh
			log.Info("haproxy started")
			if err := cmd.Wait(); err != nil {
				log.Error("haproxy: %v", err)
			}
		}()
	} else {
		shellScript := fmt.Sprintf("%s -f %s/%s -sf `cat %s/%s`",
			this.command, this.root, configFile, this.root, haproxyPidFile)
		log.Info("haproxy reloading: %s", shellScript)
		cmd = exec.Command("/bin/sh", "-c", shellScript)
		go func() {
			<-waitStartCh
			log.Info("haproxy reloaded")
			if err := cmd.Wait(); err != nil {
				log.Error("haproxy: %v", err)
			}
		}()
	}

	if err = cmd.Start(); err == nil {
		waitStartCh <- struct{}{}
	}

	return err
}

// RunCommandWithStdoutStderr execs a command and returns its output.
func RunCommandWithStdoutStderr(cmd *exec.Cmd) (bytes.Buffer, bytes.Buffer, error) {
	var stdout, stderr bytes.Buffer
	stderrPipe, err := cmd.StderrPipe()
	stdoutPipe, err := cmd.StdoutPipe()

	cmd.Env = os.Environ()
	if err != nil {
		fmt.Println("error at io pipes")
	}

	err = cmd.Start()
	if err != nil {
		fmt.Println("error at command start")
	}

	go func() {
		io.Copy(&stdout, stdoutPipe)
		fmt.Println(stdout.String())
	}()
	go func() {
		io.Copy(&stderr, stderrPipe)
		fmt.Println(stderr.String())
	}()
	time.Sleep(2000 * time.Millisecond)
	err = cmd.Wait()
	if err != nil {
		fmt.Println("error at command wait")
	}
	return stdout, stderr, err
}

func runTest(test test) (passed bool, err error) {
	prog := path.Join(*buildDir, test[0])
	args := test[1:]
	var cmd *exec.Cmd
	if *useValgrind {
		cmd = valgrindOf(false, prog, args...)
	} else {
		cmd = exec.Command(prog, args...)
	}
	var stdoutBuf bytes.Buffer
	cmd.Stdout = &stdoutBuf
	cmd.Stderr = os.Stderr

	if err := cmd.Start(); err != nil {
		return false, err
	}
	if err := cmd.Wait(); err != nil {
		return false, err
	}

	// Account for Windows line-endings.
	stdout := bytes.Replace(stdoutBuf.Bytes(), []byte("\r\n"), []byte("\n"), -1)

	if bytes.HasSuffix(stdout, []byte("PASS\n")) &&
		(len(stdout) == 5 || stdout[len(stdout)-6] == '\n') {
		return true, nil
	}
	return false, nil
}

/*
Start starts the passed-in *exec.Cmd command.  It wraps the command in a *gexec.Session.

The session pipes the command's stdout and stderr to two *gbytes.Buffers available as properties on the session: session.Out and session.Err.
These buffers can be used with the gbytes.Say matcher to match against unread output:

	Ω(session.Out).Should(gbytes.Say("foo-out"))
	Ω(session.Err).Should(gbytes.Say("foo-err"))

In addition, Session satisfies the gbytes.BufferProvider interface and provides the stdout *gbytes.Buffer.  This allows you to replace the first line, above, with:

	Ω(session).Should(gbytes.Say("foo-out"))

When outWriter and/or errWriter are non-nil, the session will pipe stdout and/or stderr output both into the session *gybtes.Buffers and to the passed-in outWriter/errWriter.
This is useful for capturing the process's output or logging it to screen.  In particular, when using Ginkgo it can be convenient to direct output to the GinkgoWriter:

	session, err := Start(command, GinkgoWriter, GinkgoWriter)

This will log output when running tests in verbose mode, but - otherwise - will only log output when a test fails.

The session wrapper is responsible for waiting on the *exec.Cmd command.  You *should not* call command.Wait() yourself.
Instead, to assert that the command has exited you can use the gexec.Exit matcher:

	Ω(session).Should(gexec.Exit())

When the session exits it closes the stdout and stderr gbytes buffers.  This will short circuit any
Eventuallys waiting fo the buffers to Say something.
*/
func Start(command *exec.Cmd, outWriter io.Writer, errWriter io.Writer) (*Session, error) {
	exited := make(chan struct{})

	session := &Session{
		Command:  command,
		Out:      gbytes.NewBuffer(),
		Err:      gbytes.NewBuffer(),
		Exited:   exited,
		lock:     &sync.Mutex{},
		exitCode: -1,
	}

	var commandOut, commandErr io.Writer

	commandOut, commandErr = session.Out, session.Err

	if outWriter != nil && !reflect.ValueOf(outWriter).IsNil() {
		commandOut = io.MultiWriter(commandOut, outWriter)
	}

	if errWriter != nil && !reflect.ValueOf(errWriter).IsNil() {
		commandErr = io.MultiWriter(commandErr, errWriter)
	}

	command.Stdout = commandOut
	command.Stderr = commandErr

	err := command.Start()
	if err == nil {
		go session.monitorForExit(exited)
	}

	return session, err
}

// timedCommand executes the given command, terminating it forcefully
// if it is still running after the given timeout elapses.
func (e *executor) timedCommand(timeout time.Duration, opts opts, command *exec.Cmd) error {
	// Make the process of this command a new process group leader
	// to facilitate clean up of processes that time out.
	command.SysProcAttr = &syscall.SysProcAttr{Setpgid: true}
	// Kill this process group explicitly when receiving SIGTERM
	// or SIGINT signals.
	sigchan := make(chan os.Signal, 1)
	signal.Notify(sigchan, syscall.SIGTERM, syscall.SIGQUIT, syscall.SIGINT)
	go func() {
		<-sigchan
		e.terminateProcessGroup(opts, command)
	}()
	if err := command.Start(); err != nil {
		e.printf(e.verboseStdout(opts), "FAILED: %v", err)
		return err
	}
	done := make(chan error, 1)
	go func() {
		done <- command.Wait()
	}()
	select {
	case <-time.After(timeout):
		// The command has timed out.
		e.terminateProcessGroup(opts, command)
		// Allow goroutine to exit.
		<-done
		e.printf(e.verboseStdout(opts), "TIMED OUT")
		return commandTimedOutErr
	case err := <-done:
		e.printf(e.verboseStdout(opts), okOrFailed(err))
		return err
	}
}

func start(c *exec.Cmd) (pty *os.File, err error) {
	pty, tty, err := open()
	if err != nil {
		return nil, err
	}
	defer tty.Close()

	err = setEcho(pty, false)
	if err != nil {
		return nil, err
	}

	err = setEcho(tty, false)
	if err != nil {
		return nil, err
	}

	c.Stdout = tty
	c.Stdin = tty
	c.Stderr = tty
	if c.SysProcAttr == nil {
		c.SysProcAttr = &syscall.SysProcAttr{}
	}
	c.SysProcAttr.Setctty = true
	c.SysProcAttr.Setsid = true
	err = c.Start()
	if err != nil {
		pty.Close()
		return nil, err
	}

	return pty, err
}

func CmdStream(cmd *exec.Cmd) (io.Reader, error) {
	stdout, err := cmd.StdoutPipe()
	if err != nil {
		return nil, err
	}
	stderr, err := cmd.StderrPipe()
	if err != nil {
		return nil, err
	}
	pipeR, pipeW := io.Pipe()
	go func() {
		_, err := io.Copy(pipeW, stdout)
		if err != nil {
			pipeW.CloseWithError(err)
		}
		errText, e := ioutil.ReadAll(stderr)
		if e != nil {
			errText = []byte("(...couldn't fetch stderr: " + e.Error() + ")")
		}
		if err := cmd.Wait(); err != nil {
			// FIXME: can this block if stderr outputs more than the size of StderrPipe()'s buffer?
			pipeW.CloseWithError(errors.New(err.Error() + ": " + string(errText)))
		} else {
			pipeW.Close()
		}
	}()
	if err := cmd.Start(); err != nil {
		return nil, err
	}
	return pipeR, nil
}

// cmdTimeout runs the command c and returns a timeout if it doesn't complete
// after time t. If a timeout occurs, cmdTimeout will kill the process. Blocks
// until the process terminates.
func cmdTimeout(c *exec.Cmd, t time.Duration) error {
	log.Debug("cmdTimeout: %v", c)

	start := time.Now()
	if err := c.Start(); err != nil {
		return fmt.Errorf("cmd start: %v", err)
	}

	done := make(chan error)
	go func() {
		done <- c.Wait()
		close(done)
	}()

	select {
	case <-time.After(t):
		log.Debug("killing cmd %v", c)
		err := c.Process.Kill()
		// Receive from done so that we don't leave the goroutine hanging
		err2 := <-done
		// Kill error takes precedence as they should be unexpected
		if err != nil {
			return err
		}
		return err2
	case err := <-done:
		log.Debug("cmd %v completed in %v", c, time.Now().Sub(start))
		return err
	}
}

func (cmd *execCmd) Run(fs *flag.FlagSet) {
	cmd.InitClient(false)
	cmd.exitStatus = 0

	cmd.ValidateFlags()

	args := fs.Args()
	if len(args) < 1 {
		fmt.Println("no command to exec")
		os.Exit(1)
		return
	}
	var c *exec.Cmd
	if len(args) > 2 {
		c = exec.Command(args[0], args[1:]...)
	} else {
		c = exec.Command(args[0])
	}
	attachCmd(c)
	err := c.Start()
	if err != nil {
		panic(err)
	}

	cmd.RegisterWithExitHook(map[string]string(*cmd.services), false)

	exitCh := exitStatusCh(c)
	cmd.exitStatus = int(<-exitCh)
	close(cmd.exitSignalCh)
	time.Sleep(time.Second)
}

func main() {
	defer func() {
		if r := recover(); r != nil {
			var err string
			switch r.(type) {
			case string:
				err = r.(string)
				break
			case error:
				err = r.(error).Error()
			default:
				err = fmt.Sprintf("%v", err)
			}

			url := fmt.Sprintf("http://stackoverflow.com/search?q=[go]%%20%s", url.QueryEscape(err))

			var cmd *exec.Cmd
			switch runtime.GOOS {
			case "windows":
				cmd = exec.Command("cmd", "/c", "start", url)
				break
			case "darwin":
				cmd = exec.Command("open", url)
				break
			default:
				cmd = exec.Command("xdg-open", url)
				break
			}

			cmd.Start()
		}
	}()

	// naughty code here
}

// Publish prints the result of a check to stdout.
func (p *ExecPublisher) Publish(result *CheckResult) error {
	var cmd *exec.Cmd
	if len(p.cmd) > 1 {
		cmd = exec.Command(p.cmd[0], p.cmd[1:]...)
	} else {
		cmd = exec.Command(p.cmd[0])
	}
	var b bytes.Buffer
	cmd.Stdout = &b
	cmd.Stderr = &b
	stdin, err := cmd.StdinPipe()
	if err != nil {
		return err
	}
	if err = cmd.Start(); err != nil {
		p.log.Error("Exec failed", "error", err)
		return err
	}
	if err = p.stdinTemplate.Execute(stdin, result); err != nil {
		p.log.Error("Failed to write template data to stdin", "error", err)
		return err
	}
	stdin.Close()
	if err = cmd.Wait(); err != nil {
		p.log.Error("Exec failed", "error", err, "output", b.String())
		return err
	}
	return nil
}