Anyway to have errors/warnings go to stderr and info/debug to stdout

[gemscoder]

Hi,
Is it possible for zerolog to log errors/warnings to stderr and everything else to stdout or do I need to use 2 different loggers ?I am using kubernetes environment thank for you help in advance.

[rs]

You can implement a zerolog.LevelWriter that would use the level to choose between os.Stdout and os.Stderr.

[gemscoder]

Thanks for your reply. That helps. Any sample code?

[rs]

You can find some example in the writer.go file.

[mitar]

This has also been discussed here.

[v613]

@gemscoder here is my little contribution.

package main

import (
	"io"
	"os"

	"github.com/rs/zerolog"
)

type myWriter struct {
	io.Writer
	ErrOut io.Writer
}

func (mw myWriter) WriteLevel(lvl zerolog.Level, txt []byte) (int, error) {
	if lvl > zerolog.InfoLevel {
		// return os.Stderr.Write(txt)
		return mw.ErrOut.Write(txt)
	}
	return mw.Writer.Write(txt)
}

func main() {
	out := myWriter{os.Stdout, os.Stderr}
	l := zerolog.New(out)
	l.Info().Msg("to standard out")
	l.Error().Msg("to standard error")
}

go run main.go 2> >(sed 's/^/stderr: /') > >(sed 's/^/stdout: /')
stdout: {"level":"info","message":"to standard out"}
stderr: {"level":"error","message":"to standard error"}

$ go run main.go 2> err.log
{"level":"info","message":"to standard out"}
$ cat err.log 
{"level":"error","message":"to standard error"}
$

We could probably close this issue, especially since it's from 2021.