logger.go

package main

import (
	"encoding/hex"
	"fmt"
	"io"
	"os"
	"reflect"
	"slices"
	"strings"

	"github.com/rs/zerolog"
	"github.com/rs/zerolog/log"
	"gopkg.in/natefinch/lumberjack.v2"
)

var globalInst *logger

type logger struct {
	writer io.Writer
}

func InitGlobalLogger() {
	writers := []io.Writer{}

	if slices.Contains(config.LogTargets, "file") {
		fileWriter := &lumberjack.Logger{
			Filename: config.LogFilename,
			MaxSize:  config.LogFileMaxSize,
			Compress: config.LogFileCompress,
		}
		writers = append(writers, fileWriter)
	}

	if slices.Contains(config.LogTargets, "console") {
		writers = append(writers, zerolog.ConsoleWriter{Out: os.Stderr, TimeFormat: "15:04:05"})
	}

	globalInst = &logger{
		writer: io.MultiWriter(writers...),
	}

	level, err := zerolog.ParseLevel(strings.ToLower(config.LogLevel))
	if err != nil {
		level = zerolog.InfoLevel
	}
	zerolog.SetGlobalLevel(level)

	log.Logger = zerolog.New(globalInst.writer).With().Timestamp().Logger()
}

func addFields(event *zerolog.Event, keyvals ...any) *zerolog.Event {
	if len(keyvals)%2 != 0 {
		keyvals = append(keyvals, "!MISSING-VALUE!")
	}

	for i := 0; i < len(keyvals); i += 2 {
		key, ok := keyvals[i].(string)
		if !ok {
			key = "!INVALID-KEY!"
		}

		value := keyvals[i+1]
		switch typ := value.(type) {
		case fmt.Stringer:
			if isNil(typ) {
				event.Any(key, typ)
			} else {
				event.Stringer(key, typ)
			}
		case error:
			event.AnErr(key, typ)
		case []byte:
			event.Str(key, hex.EncodeToString(typ))
		default:
			event.Any(key, typ)
		}
	}

	return event
}

func Trace(msg string, keyvals ...any) {
	addFields(log.Trace(), keyvals...).Msg(msg)
}

func Debug(msg string, keyvals ...any) {
	addFields(log.Debug(), keyvals...).Msg(msg)
}

func Info(msg string, keyvals ...any) {
	addFields(log.Info(), keyvals...).Msg(msg)
}

func Warn(msg string, keyvals ...any) {
	addFields(log.Warn(), keyvals...).Msg(msg)
}

func Error(msg string, keyvals ...any) {
	addFields(log.Error(), keyvals...).Msg(msg)
}

func Fatal(msg string, keyvals ...any) {
	addFields(log.Fatal(), keyvals...).Msg(msg)
}

func Panic(msg string, keyvals ...any) {
	addFields(log.Panic(), keyvals...).Msg(msg)
}

func isNil(i any) bool {
	if i == nil {
		return true
	}

	if reflect.TypeOf(i).Kind() == reflect.Ptr {
		return reflect.ValueOf(i).IsNil()
	}

	return false
}