how to get correct file when I wrap a logger in go?

I use a global logger like this:

[root@dev log]# cat src/logging/logging.go 
package logging

import (
	"log"
	"os"
)

var Logger *log.Logger

func init() {
	Logger = log.New(os.Stdout, "[Debug]", log.Llongfile|log.LstdFlags)
}

func Debug(format string, v ...interface{}) {
	Logger.SetPrefix("[Debug] ")
	Logger.Printf(format, v...)
}

[root@dev log]# cat src/main/main.go 
package main

import "logging"

func main() {
	logging.Debug("in main")
}

Here in main function I want to get:

[Debug] 2015/12/10 22:20:23 /tmp/log/src/main/main.go:6: in main

But I get following output instead:

[Debug] 2015/12/10 22:20:23 /tmp/log/src/logging/logging.go:16: in main

How can I get the correct file which calling the logger?

Instead of using logger.Printf, you need to use the raw logger.Output function, and provide the correct callDepth for the call point (the default is 2).

If you look at the code for Logger.Printf, you can see how it's done by default:

func (l *Logger) Printf(format string, v ...interface{}) {
    l.Output(2, fmt.Sprintf(format, v...))
}