logger.go

package logger

import (
	"fmt"
	"io"
	"io/ioutil"
	"log"
	"os"
	"path"
	"runtime"
	"time"
)

func init() {
	setDefaultOutputs()
}

// SetupLogger configure logger instance with user provided settings
func SetupLogger() (err error) {
	if *Logger.Enabled {
		err = setupOutputs()
		if err != nil {
			return
		}
		logLevel()
		if Logger.ColourOutput {
			colourOutput()
		}
	} else {
		clearAllLoggers()
	}
	return
}

// setDefaultOutputs() this setups defaults used by the logger
// This allows it to be used without any user configuration
func setDefaultOutputs() {
	debugLogger = log.New(os.Stdout,
		"[DEBUG]: ",
		log.Ldate|log.Ltime)

	infoLogger = log.New(os.Stdout,
		"[INFO]:  ",
		log.Ldate|log.Ltime)

	warnLogger = log.New(os.Stdout,
		"[WARN]:  ",
		log.Ldate|log.Ltime)

	errorLogger = log.New(os.Stdout,
		"[ERROR]: ",
		log.Ldate|log.Ltime)

	fatalLogger = log.New(os.Stdout,
		"[FATAL]: ",
		log.Ldate|log.Ltime)
}

// colorOutput() sets the prefix of each log type to matching colour
// TODO: add windows support
func colourOutput() {
	if runtime.GOOS != "windows" || Logger.ColourOutputOverride {
		debugLogger.SetPrefix("\033[34m[DEBUG]\033[0m: ")
		infoLogger.SetPrefix("\033[32m[INFO]\033[0m: ")
		warnLogger.SetPrefix("\033[33m[WARN]\033[0m: ")
		errorLogger.SetPrefix("\033[31m[ERROR]\033[0m: ")
		fatalLogger.SetPrefix("\033[31m[FATAL]\033[0m: ")
	}
}

// clearAllLoggers() sets all logger flags to 0 and outputs to Discard
func clearAllLoggers() {
	debugLogger.SetFlags(0)
	infoLogger.SetFlags(0)
	warnLogger.SetFlags(0)
	errorLogger.SetFlags(0)
	fatalLogger.SetFlags(0)

	debugLogger.SetOutput(ioutil.Discard)
	infoLogger.SetOutput(ioutil.Discard)
	warnLogger.SetOutput(ioutil.Discard)
	errorLogger.SetOutput(ioutil.Discard)
	fatalLogger.SetOutput(ioutil.Discard)
}

// setupOutputs() sets up the io.writer to use for logging
// TODO: Fix up rotating at the moment its a quick job
func setupOutputs() (err error) {
	if len(Logger.File) > 0 {
		logFile := path.Join(LogPath, Logger.File)
		if Logger.Rotate {
			if _, err = os.Stat(logFile); !os.IsNotExist(err) {
				currentTime := time.Now()
				newName := currentTime.Format("2006-01-02 15-04-05")
				newFile := newName + " " + Logger.File
				err = os.Rename(logFile, path.Join(LogPath, newFile))
				if err != nil {
					err = fmt.Errorf("Failed to rename old log file %s", err)
					return
				}
			}
		}
		logFileHandle, err = os.OpenFile(logFile, os.O_RDWR|os.O_CREATE|os.O_APPEND, 0666)
		if err != nil {
			return
		}
		logOutput = io.MultiWriter(os.Stdout, logFileHandle)
	} else {
		logOutput = os.Stdout
	}
	return
}

// CloseLogFile close the handler for any open log files
func CloseLogFile() (err error) {
	if logFileHandle != nil {
		err = logFileHandle.Close()
	}
	return
}