gologger/format.go

// Package gologger provides a simple logging implementation with multiple appenders and formatters.
// It supports console, file, and HTTP logging with customizable formats.
package gologger

import (
	"encoding/json"
	"fmt"
	"strings"
)

// LogFormatter is a function type that formats a LogEvent into a string.
// Example:
//
//	formatter := func(event LogEvent) string {
//	  return fmt.Sprintf("[%s] %s: %v", event.Ts.Format("2006-01-02"), event.Level, event.Data)
//	}
type LogFormatter = func(LogEvent) string

const logTemplate = "[%s] %s : %s - %s\n"

// format is the default formatter that converts a LogEvent to a string using the default template.
// It handles both simple values and formatted strings.
// Template: "[timestamp] level : category - data"
func format(logEvent LogEvent) string {
	data := logEvent.Ts.Format("2006-01-02 15:04:05")
	msg := ""
	firstMsg := logEvent.Data[0]
	if isFormatString(firstMsg) {
		msg = fmt.Sprintf(firstMsg.(string), logEvent.Data[1:]...)
	} else {
		msg = sprint(logEvent.Data)
	}

	ret := fmt.Sprintf(logTemplate, data, logEvent.Category, getLogLevelStr(logEvent.Level), msg)
	return ret
}

func getLogLevelStr(level int) string {
	for name, slevel := range logLevelMap {
		if slevel == level {
			return strings.ToUpper(name)
		}
	}
	return "Unknown"
}

func isFormatString(f interface{}) bool {
	s, ok := f.(string)
	if !ok {
		return false
	}
	// 尝试使用空接口来格式化字符串
	m := fmt.Sprintf(s, []interface{}{}...)
	return strings.Contains(m, "MISSING")
}

func sprint(s []interface{}) string {
	str := make([]any, len(s))
	for i, v := range s {
		if i > 0 {
			str[i] = fmt.Sprintf(" %v", v)
		} else {
			str[i] = fmt.Sprintf("%v", v)
		}
	}
	return fmt.Sprint(str...)
}

func jsonFormatter(logEvent LogEvent) string {
	_, err := json.Marshal(logEvent.Data)
	if err != nil {
		logEvent.Data = []interface{}{fmt.Sprintf("%v", logEvent.Data)}
	}
	d, _ := json.Marshal(logEvent)
	return string(d)
}

func SelectFormatter(formatter string) LogFormatter {
	switch strings.ToLower(formatter) {
	case "json":
		return jsonFormatter
	case "text":
		return format
	default:
		return format
	}
}