Change logrus to slog

Signed-off-by: Asai Neko <sugar@sne.moe>

logger/slog.go

@@ -0,0 +1,47 @@
+package logger
+
+import (
+	"io"
+	"log/slog"
+	"os"
+	"strings"
+)
+
+func Init() {
+	levelStr := strings.ToLower(os.Getenv("LOG_LEVEL"))
+	var level slog.Level
+	switch levelStr {
+	case "debug":
+		level = slog.LevelDebug
+	case "warn":
+		level = slog.LevelWarn
+	case "error":
+		level = slog.LevelError
+	default:
+		level = slog.LevelInfo
+	}
+
+	file, err := os.OpenFile("app.log", os.O_APPEND|os.O_CREATE|os.O_RDWR, 0666)
+	var writer io.Writer = os.Stdout
+	if err != nil {
+		slog.Error("Error to create log file", "err", err)
+	} else {
+		writer = io.MultiWriter(os.Stdout, file)
+	}
+
+	opts := &slog.HandlerOptions{
+		Level:     level,
+		AddSource: true,
+		ReplaceAttr: func(groups []string, a slog.Attr) slog.Attr {
+			if a.Key == slog.TimeKey {
+				return slog.String(a.Key, a.Value.Time().Format("2006-01-02 15:04:05"))
+			}
+			return a
+		},
+	}
+
+	handler := slog.NewJSONHandler(writer, opts)
+
+	logger := slog.New(handler)
+	slog.SetDefault(logger)
+}