func()

in openwhisk/executor.go [128:187]

• 49 lines of code
• 10 McCabe index (conditional complexity)

func (proc *Executor) Start(waitForAck bool) error {
	// start the underlying executable
	Debug("Start:")
	err := proc.cmd.Start()
	if err != nil {
		Debug("run: early exit: %e", err)
		proc.cmd = nil // no need to kill
		return fmt.Errorf("command exited")
	}
	Debug("pid: %d", proc.cmd.Process.Pid)

	go func() {
		proc.cmd.Wait()
		proc.exited <- true
	}()

	// not waiting for an ack, so use a timeout
	if !waitForAck {
		select {
		case <-proc.exited:
			return fmt.Errorf("command exited")
		case <-time.After(DefaultTimeoutStart):
			return nil
		}
	}

	// wait for acknowledgement
	Debug("waiting for an ack")
	ack := make(chan error)
	go func() {
		out, err := proc.output.ReadBytes('\n')
		Debug("received ack %s", out)
		if err != nil {
			ack <- err
			return
		}
		// parse ack
		var ackData ActionAck
		err = json.Unmarshal(out, &ackData)
		if err != nil {
			ack <- err
			return
		}
		// check ack
		if !ackData.Ok {
			ack <- fmt.Errorf("The action did not initialize properly.")
			return
		}
		ack <- nil
	}()
	// wait for ack or unexpected termination
	select {
	// ack received
	case err = <-ack:
		return err
	// process exited
	case <-proc.exited:
		return fmt.Errorf("Command exited abruptly during initialization.")
	}
}