How to get file and function name for loggers - go

Question

I'm using logrus OS which works as expected, now we have a requirement to add to the logger output the file and the function which from where you put the logger call,
we need it to be something like
File log-ut-usage
func main(){
logs := lts.InitLogger("test","1","debug")
logs.Debugf("test 123")
....
}
This is the required output
{"file":"log-ut-usage/main.go:21","function":"main","level":"warn","test 123":"ddd","timestamp":"2019-10-02T09:21:39.309559Z"}
currently we got the file and function of the
file logger.go
func InitLog(label string) LoggerI {
loggerImpl = &logrus.Logger{
Out: os.Stdout,
Level: level,
ReportCaller: true,
Formatter: &logrus.JSONFormatter{
TimestampFormat: timestampFormat,
CallerPrettyfier: func(f *runtime.Frame) (string, string) {
s := strings.Split(f.Function, ".")
funcname := s[len(s)-1]
_, filename := path.Split(f.File)
return funcname, filename
},
},
}
This is the (unwanted) output
{"file":"logger.go","func":"InitLog","level":"debug","msg":"test 123","time":"2019-10-02 12:21:39"}
I dont want to get the file logger.go where we coded the json formater, I want to get the file that with the usage of the logger .

Answer 1

You can wrap your logger with file, function and line information and then use that.
Here's an example (live):
package main
import (
"os"
"runtime"
"strconv"
"strings"
log "github.com/sirupsen/logrus"
)
func init() {
log.SetFormatter(&log.JSONFormatter{})
log.SetOutput(os.Stdout)
}
func logger() *log.Entry {
pc, file, line, ok := runtime.Caller(1)
if !ok {
panic("Could not get context info for logger!")
}
filename := file[strings.LastIndex(file, "/")+1:] + ":" + strconv.Itoa(line)
funcname := runtime.FuncForPC(pc).Name()
fn := funcname[strings.LastIndex(funcname, ".")+1:]
return log.WithField("file", filename).WithField("function", fn)
}
func test() {
logger().Info("Testing...")
}
func main() {
logger().Info("Testing...")
test()
}
Output:
{"file":"prog.go:34","function":"main","level":"info","msg":"Testing...","time":"2009-11-10T23:00:00Z"}
{"file":"prog.go:30","function":"test","level":"info","msg":"Testing...","time":"2009-11-10T23:00:00Z"}

Answer 2

Have you tried to use debug.Stack() to fetch the file name which calls InitLog?
https://play.golang.org/p/g6yLGsiuEEn
goroutine 1 [running]:
runtime/debug.Stack(0x15d6b0, 0x3, 0x68360, 0x1580)
/usr/local/go/src/runtime/debug/stack.go:24 +0xc0
main.fun2()
/tmp/sandbox834348417/prog.go:20 +0x20
main.fun1(...)
/tmp/sandbox834348417/prog.go:15
main.main()
/tmp/sandbox834348417/prog.go:10 +0x20
Hope it works.