add checking detect

lib/taskMoniter.mjs

@@ -14,6 +14,8 @@ class TaskMoniter {
 
   constructor(task_list_dir) {
     this.check_time_gap = 10;           //检测间隔时间，单位：秒
+    this.checking = false;
+
     this.task_dir = task_list_dir;      //监控目录：任务列表保存目录
     this.tasks = {};                    //内存中的任务列表
     this.taskStatus = {                 //当前任务状态
@@ -42,16 +44,31 @@ class TaskMoniter {
   }
 
   async checkTasks() {
+    if (this.checking == true) {
+        return;
+    }
+
+    try {
+        this.checking = true;
+
+        //do something
+        console.log('[%s] TaskMoniter auto check...', common.getTimeString());
+
+
+        this.checking = false;
+    }catch(error) {
+        this.checking = false;
+    }
   }
 
   run() {     //开始监控任务目录，把所有任务缓存到内存
     console.log('[%s] TaskMoniter started.', common.getTimeString());
 
     //auto run
+    const _self = this;
     const task_check_time = this.check_time_gap;
     const task_auto_run = cron.schedule(`*/${task_check_time} * * * * *`, () =>  {
-        console.log('[%s] TaskMoniter auto check...', common.getTimeString());
-
+        _self.checkTasks();
     }, {
         scheduled: false
     });