golang gists

log-to-file.go

f, err := os.OpenFile("testlogfile", os.O_RDWR | os.O_CREATE | os.O_APPEND, 0666)
if err != nil {
    t.Fatalf("error opening file: %v", err)
}
defer f.Close()

log.SetOutput(f)
log.Println("This is a test log entry")

simple-sched.go

// sched to start scheduler job at start time by interval duration.
func sched(jobFunc interface{}, start, interval string, jobArgs ...interface{}) {
	jobValue := reflect.ValueOf(jobFunc)
	if jobValue.Kind() != reflect.Func {
		log.Panic("only function can be schedule.")
	}
	if len(jobArgs) != jobValue.Type().NumIn() {
		log.Panic("The number of args valid.")
	}
	// Get job function args.
	in := make([]reflect.Value, len(jobArgs))
	for i, arg := range jobArgs {
		in[i] = reflect.ValueOf(arg)
	}

	d, err := time.ParseDuration(interval)
	if err != nil {
		log.Panic(err)
	}
	location, err := time.LoadLocation("Asia/Shanghai")
	if err != nil {
		log.Panic(err)
	}
	t, err := time.ParseInLocation("15:04:05", start, location)
	if err != nil {
		log.Panic(err)
	}
	now := time.Now()

	// Start time.
	t = time.Date(now.Year(), now.Month(), now.Day(), t.Hour(), t.Minute(), t.Second(), 0, location)

	if now.After(t) {
		t = t.Add((now.Sub(t)/d + 1) * d)
	}

	time.Sleep(t.Sub(now))
	go jobValue.Call(in)
	ticker := time.NewTicker(d)
	go func() {
		for _ = range ticker.C {
			go jobValue.Call(in)
		}
	}()
}