http-boot-config/config/logger/logger.go

package logger

import (
	"fmt"
	"io"
	"os"
)

const (
	nc     = "\033[0m"
	red    = "\033[0;31m"
	yellow = "\033[0;33m"
	gray   = "\033[0;30m"
)

const (
	errorPrefix   = "Error: "
	fatalPrefix   = "Fatal: "
	warningprefix = "Warning: "
	debugprefix   = "Debug: "
)

type SimpleLogger struct {
	enableColour bool
	debug        bool
}

func (sl *SimpleLogger) printMsg(msg string, dest io.Writer) {
	if msg[len(msg)-1:] != "\n" {
		msg = msg + "\n"
	}

	n, err := fmt.Fprint(dest, msg)
	if err != nil {
		panic(fmt.Errorf("failed to write message to %v: %w", dest, err))
	}
	if n != len(msg) {
		panic(fmt.Errorf("failed to write the entire message (%d/%d)", n, len(msg)))
	}
}

func (sl *SimpleLogger) colourText(msg string, colour string) string {
	if !sl.enableColour {
		return msg
	}
	return colour + msg + nc
}

func (sl *SimpleLogger) Info(msg string) {
	sl.printMsg(msg, os.Stdout)
}

func (sl *SimpleLogger) Infof(format string, a ...any) {
	sl.printMsg(fmt.Sprintf(format, a...), os.Stdout)
}

func (sl *SimpleLogger) Error(msg string) {
	sl.printMsg(sl.colourText(errorPrefix+msg, red), os.Stderr)
}

func (sl *SimpleLogger) Errorf(format string, a ...any) {
	sl.printMsg(sl.colourText(errorPrefix+fmt.Sprintf(format, a...), red), os.Stderr)
}

func (sl *SimpleLogger) Warning(msg string) {
	sl.printMsg(sl.colourText(warningprefix+msg, yellow), os.Stdout)
}

func (sl *SimpleLogger) Warningf(format string, a ...any) {
	sl.printMsg(sl.colourText(warningprefix+fmt.Sprintf(format, a...), yellow), os.Stdout)
}

func (sl *SimpleLogger) Debug(msg string) {
	if !sl.debug {
		return
	}
	sl.printMsg(sl.colourText(debugprefix+msg, gray), os.Stdout)
}

func (sl *SimpleLogger) Debugf(format string, a ...any) {
	if !sl.debug {
		return
	}
	sl.printMsg(sl.colourText(debugprefix+fmt.Sprintf(format, a...), gray), os.Stdout)
}
func (sl *SimpleLogger) Fatal(msg string) {
	sl.printMsg(sl.colourText(fatalPrefix+msg, red), os.Stderr)
	os.Exit(1)
}

func (sl *SimpleLogger) Fatalf(format string, a ...any) {
	sl.printMsg(sl.colourText(fatalPrefix+fmt.Sprintf(format, a...), red), os.Stderr)
	os.Exit(1)
}

func New(colour, debug bool) *SimpleLogger {
	return &SimpleLogger{
		debug:        debug,
		enableColour: colour,
	}
}