Custom package Logger doesn't work for other files

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1

Hello everyone, I have an issue to use the different logs from my custom Logger package in other files of the project. So here is my Logger package with InitLogs() method.
I have only one module in the application ‘ConsulGitOpsOperator/packages’ and all other custom packages are located here. I can use Methods from other packages in main function, but for some reason the Logger package doesn’t work for other files. Could you please help me to find a solution?

Any help is appreciated!!

package Logger

import (
	"ConsulGitOpsOperator/packages/Config"
	"flag"
	"fmt"
	"io"
	"log"
	"os"
)

var (
	Info    *log.Logger
	Warning *log.Logger
	Error   *log.Logger
)

func InitLogs() {
	logPath := fmt.Sprintf("%s%s", Config.WorkingDir(), "\\appLogs.txt")
	flag.Parse()
	logFile, err := os.OpenFile(logPath, os.O_APPEND|os.O_WRONLY|os.O_CREATE, 0666)
	if err != nil {
		fmt.Printf("Error creating log file: %v\n", err)
		os.Exit(1)
	}
	defer logFile.Close()
	writer := io.Writer(logFile)
	flags := log.Ldate | log.Ltime | log.Lshortfile
	Info = log.New(writer, "INFO: ", flags)
	Warning = log.New(writer, "WARNING: ", flags)
	Error = log.New(writer, "ERROR: ", flags)
	writeLog := io.MultiWriter(os.Stdout, writer)
	log.SetOutput(writeLog)
	Warning.Println("LogFile : " + logPath)	// the output is saved in the logFile
}

And this is the way how I import it and use in the main function

package main

import (
	"ConsulGitOpsOperator/packages/GenerateACLTokens"
	Logger "ConsulGitOpsOperator/packages/Logger"
)

func main() {

	Logger.InitLogs()
	Logger.Info.Println("This is an Info")  // the output is NOT saved in the logFile
	err := GenerateACLTokens.StartGeneratingToken()
	if err != nil {
		Logger.Error.Println("Error", err)  // the output is NOT saved in the logFile
	}
}
2

Can you clarify what you mean by “doesn’t work?” Are you getting an error, or is it not behaving how you would expect?

3

It is not behaving as I would expect. For example, you see in the main function I added in the second line a log message ‘Logger.Info.Println(“This is an Info”) // the output is NOT saved in the logFile’ and this message or any other message throughout the application will not be saved in the log file which I create in the method InitLogs. I want to save all the error, warning and info messages in that single file.

4

You close the file when InitLogs returns. You can’t write to the closed file later. Is there no panic?

Isn’t this redundant? *File already implements Writer.

5

Where should I close the logFile, on which line? Maybe outside of the function InitLogs?

The logFile itself has type of os.File, that’s why I thought iy should have wrapped it as a io.writer.

6

  • You can return the logFile from InitLogs and defer its closure in main.

  • A Tour of Go

1 Like
7

Another option is for InitLogs to return a function to close the log file(s):

func InitLogs() (closer func() error) {
	// ...
	return logFile.Close
}

func main() {
	closeLogs := Logger.InitLogs()
	defer closeLogs()
	// ...
}
2 Likes