global variable 'cpuOut' is always nil

[RemoteOnly]

package service

...
var cpuOut *os.File
...

// BeforeRun takes care of necessary actions such as creating files
// before the beat should run.
func BeforeRun() {
	logger := logp.NewLogger("service")
	if withCPUProfile() {
		cpuOut, err := os.Create(*cpuprofile)
		....
	}

	...
}

cpuOut, err := os.Create(*cpuprofile) will create a new variable cpuOut, which is different with global variable var cpuOut *os.File. Global variable var cpuOut *os.File is never set and one error will be created when function Cleanup() is called.

func Cleanup() {
	logger := logp.NewLogger("service")
	if withCPUProfile() {
		pprof.StopCPUProfile()
		cpuOut.Close() // -------- cpuOut is nil
	}

        ...
}

Besides, the cpuprofile will not be closed in time.