feat: 实现公共工具包，包括日志、错误处理、数据库和缓存

backend/shared/pkg/logger/logger.go

@@ -0,0 +1,38 @@
+package logger
+
+import (
+	"log"
+	"os"
+)
+
+type Logger struct {
+	infoLogger  *log.Logger
+	errorLogger *log.Logger
+	debugLogger *log.Logger
+}
+
+var instance *Logger
+
+func init() {
+	instance = NewLogger()
+}
+
+func NewLogger() *Logger {
+	return &Logger{
+		infoLogger:  log.New(os.Stdout, "INFO: ", log.Ldate|log.Ltime|log.Lshortfile),
+		errorLogger: log.New(os.Stderr, "ERROR: ", log.Ldate|log.Ltime|log.Lshortfile),
+		debugLogger: log.New(os.Stdout, "DEBUG: ", log.Ldate|log.Ltime|log.Lshortfile),
+	}
+}
+
+func Info(format string, v ...interface{}) {
+	instance.infoLogger.Printf(format, v...)
+}
+
+func Error(format string, v ...interface{}) {
+	instance.errorLogger.Printf(format, v...)
+}
+
+func Debug(format string, v ...interface{}) {
+	instance.debugLogger.Printf(format, v...)
+}