added check_isexist function

ee/core/cron.py

@@ -1,4 +1,5 @@
 from crontab import *
+from ee.core.shellexec import EEShellExec
 from ee.core.logging import Log
 
 """
@@ -7,6 +8,7 @@ Set CRON on LINUX system.
 
 class EECron():
     def setcron_daily(self,cmd,comment='Cron set by EasyEngine',user='root',min=0,hour=12):
+        if not self.check_isexist(self,cmd):
             tab = CronTab(user=user)
             cron_job = tab.new(cmd, comment=comment)
             cron_job.minute().on(min)
@@ -14,3 +16,12 @@ class EECron():
             #writes to crontab
             tab.write()
             Log.debug(self, "Cron is set:\n" + tab.render())
+
+    #Check if cron already exist
+    def check_isexist(self,cmd):
+
+         if EEShellExec.cmd_exec(self, "crontab -l | grep -q \'{0}\'".format(cmd)):
+             Log.debug(self, "Cron already exist")
+             return True
+         else:
+             return False