转到日志未出现

Question

I want to create a Dependency Injection for a logging system in golang, but when I do log.Info.Println it doesn't print anything to the log file. Here's my code:

app.go

package main

import (
    log "github.com/jass-trix/BVDI/backend/application/logging"
)

func main() {
    logger := log.InitLog()
    logger.Info.Println("test info")
    logger.Error.Println("test error")
}

init.go

package logging

import (
    "flag"
    "io"
    "log"
    "os"
)

const logPath = "log/path/"

//Logger is a struct that contain all type of logger
//logger will be separated into two level
type Logger struct {
    Info  *log.Logger
    Error *log.Logger
}

var infoLog *log.Logger
var errorLog *log.Logger

//InitLog is a function to instantiate logging
func InitLog() *Logger {

    flag.Parse()

    fileInfo, err := os.OpenFile(logPath+"file.log", os.O_CREATE|os.O_WRONLY|os.O_APPEND, 0660)
    if err != nil {
        log.Fatalf("error on opening file: %v", err)
    }
    defer fileInfo.Close()

    multiInfo := io.MultiWriter(fileInfo, os.Stdout)
    infoLog := log.New(multiInfo, "INFO: ", log.Ldate|log.Ltime|log.Lshortfile)

    fileError, err := os.OpenFile(logPath+"file.error.log", os.O_CREATE|os.O_WRONLY|os.O_APPEND, 0660)
    if err != nil {
        log.Fatalf("error on opening file: %v", err)
    }
    defer fileError.Close()

    multiError := io.MultiWriter(fileError, os.Stdout)
    errorLog := log.New(multiError, "ERROR: ", log.Ldate|log.Ltime|log.Lshortfile)
    return &Logger{
        Info:  infoLog,
        Error: errorLog,
    }
}

When I call logger.Info.Println() in app.go it doesn't print anything, but when I call errorLog.Println() in init.go it prints to the file.

Does logging support Dependency Injection?

Answer 1

In InitLog you used

defer fileInfo.Close()

It closed file after InitLog call. Then logger.Info.Println("test info") tries to write to the closed file.

If you (really) want to use global logger, you should not close file in InitLog function.