pref: 调整插件目录，增加一些帮助说明

packages/ui/certd-server/src/modules/plugin/cron/cron.ts

@@ -0,0 +1,43 @@
+import cron from 'node-cron';
+export type CronTask = {
+  /**
+   * 为空则为单次执行
+   */
+  cron: string;
+  job: () => Promise<void>;
+  name: string;
+};
+export class Cron {
+  logger;
+  constructor(opts) {
+    this.logger = opts.logger;
+  }
+
+  register(task: CronTask) {
+    if (!task.cron) {
+      this.logger.info(`[cron] register once : [${task.name}]`);
+      task.job();
+      return;
+    }
+    this.logger.info(`[cron] register cron : [${task.name}] ,${task.cron}`);
+    cron.schedule(task.cron, task.job, {
+      name: task.name,
+    });
+    this.logger.info('当前定时任务数量：', this.getListSize());
+  }
+
+  remove(taskName: string) {
+    this.logger.info(`[cron] remove : [${taskName}]`);
+    const tasks = cron.getTasks() as Map<any, any>;
+    const node = tasks.get(taskName);
+    if (node) {
+      node.stop();
+      tasks.delete(taskName);
+    }
+  }
+
+  getListSize() {
+    const tasks = cron.getTasks();
+    return tasks.size;
+  }
+}