GoEthemineTelegramBot/logger.go

package main

import (
	"io"
	"log"
	"os"
	"time"
)

type customLogWriter struct {
	Writer io.Writer
}

// Initializes Loggers
func LoggersInit() {
	fullLogPath := appSettings.FullLogPath
	errorLogPath := appSettings.ErrorLogPath

	fullLog, err := os.OpenFile(fullLogPath, os.O_CREATE|os.O_APPEND|os.O_RDWR, 0766)
	if err != nil {
		log.Panic(err)
	}
	// Prints log to os.Stdout, fullLog,
	fullLogWriter := &customLogWriter{io.MultiWriter(os.Stdout, fullLog)}

	errLog, err := os.OpenFile(errorLogPath, os.O_CREATE|os.O_APPEND|os.O_RDWR, 0766)
	if err != nil {
		log.Panic(err)
	}
	// Prints log to os.Stdout, fullLog, errLog
	errLogWriter := &customLogWriter{io.MultiWriter(os.Stdout, fullLog, errLog)}

	LogInfo = log.New(fullLogWriter, "INFO\t", 0)
	LogWarn = log.New(fullLogWriter, "WARNING\t", 0)
	LogError = log.New(errLogWriter, "ERROR\t", log.Lshortfile)
	LogDebug = log.New(fullLogWriter, "DEBUG\t", log.Lshortfile)

}

// Passes message to writer with added current time
func (writer customLogWriter) Write(message []byte) (int, error) {
	bytes := append([]byte(time.Now().Format("[01-02-2006 15:04:05] "))[:], message...)

	n, err := writer.Writer.Write(bytes)
	if err != nil {
		return n, err
	}
	if n != len(bytes) {
		return n, io.ErrShortWrite
	}
	return len(bytes), nil
}