添加数据中心的rpc 服务

src/Service/Interfaces/DatacenterServiceInterface.php

+<?php
+/**
+ * Created by PhpStorm.
+ * User: 王源
+ * Date: 2020/3/16
+ * Time: 15:07
+ */
+
+namespace Meibuyu\Micro\Service\Interfaces;
+
+interface DatacenterServiceInterface
+{
+
+    /**
+     * description:获取国家汇率 默认取最新一个汇率值
+     * author: fuyunnan
+     * @param int $currencyId 货币id
+     * @param array $field 字段
+     * @return array
+     * @throws
+     * Date: 2020/8/11
+     */
+    public function getCurrencyRate($currencyId, $field = ['id', 'currency_id', 'rate_val']): array;
+
+
+
+}
\ No newline at end of file