chore: add storage logger and handler in /int

backend/internal/logger/logger.go

@@ -0,0 +1,45 @@
+package logger
+
+import (
+	"io"
+	"log/slog"
+	"os"
+	"path/filepath"
+
+	"gopkg.in/natefinch/lumberjack.v2"
+)
+
+type Logger struct {
+	*slog.Logger
+}
+
+func New(debug bool) *Logger {
+	logDir := "/var/log/banforge"
+	if err := os.MkdirAll(logDir, 0750); err != nil {
+		return nil
+	}
+
+	fileWriter := &lumberjack.Logger{
+		Filename:   filepath.Join(logDir, "banforge.log"),
+		MaxSize:    500,
+		MaxBackups: 3,
+		MaxAge:     28,
+		Compress:   true,
+	}
+
+	var level slog.Level
+	if debug {
+		level = slog.LevelDebug
+	} else {
+		level = slog.LevelInfo
+	}
+	multiWriter := io.MultiWriter(fileWriter, os.Stdout)
+
+	handler := slog.NewTextHandler(multiWriter, &slog.HandlerOptions{
+		Level: level,
+	})
+
+	return &Logger{
+		Logger: slog.New(handler),
+	}
+}