cron_python

Cron Job implementation in python

• cron_manager: The class to be imported for using cron job functionality. It's methods are used to add, remove and modify the cron jobs.

• cron_manager class methods:

1. start_cron(): Start the cron manager. It needs to be called immediately after creating the cron_manager instance. It's a pre-requisite to all other functions.

2. new_job(function, args[, every_seconds=None, minutes=-1, hours=-1, dom=-1, months=-1]): Add a new cron job.

Arguments:

'function' : Mandatory argument. Any python function can be specified.

'args' : Mandatory argument. Arguments to the function. It should be provided as a list.

'every_seconds' : Optional. Its value should be an integer. If it's specified, the cron job is executed every 'n' seconds where 'n' is the value of argument. Default value is None.

'minutes' : Optional. It accepts argument of type list. It's the list of minute values at which the cron job is executed. Default value is -1, which is a special value meaning that the cron job is executed at every minute. The list values should be in range [0, 59].

'hours' : Optional. It accepts argument of type list. It's the list of hour values at which the cron job is executed. Default value is -1, which is a special value meaning that the cron job is executed at every hour. The list values should be in range [0, 23].

'dom': : Optional. It's short form for 'day of month'. It accepts argument of type list. It's the list of days of month values at which the cron job is executed. Default value is -1, which is a special value meaning that the cron job is executed every day. The list values should be in range [0, 31].

'months' : Optional. It accepts argument of type list. It's the list of days of month values at which the cron job is executed. Default value is -1, which is a special value meaning that the cron job is executed every month. The list values should be in range [0, 11]. (0-January, 11-December).

The return value is an object of type 'cron_obj'. This object needs to be passed to other functions (remove_job(), modify_job(), etc)

3. remove_job(job_object):

Remove the cron job, passed as an argument.

4. modify_job(job_object[, every_seconds=None, minutes=-1, hours=-1, dom=-1, months=-1]):

   Modify the cron job pass as an argument. The optional arguments are same as that of new_job() function.

Example:

import cron_manager

#Function to be passed to cron job. def keep_printing(args1, args2): with open("C:\cron_logs.log", "a") as fp: fp.write(str(args1) + str(args2) + "\n")

mgr = cron_manager.cron_manager()

#Start the cron daemon. mgr.start_cron()

#Create a cron job which gets executed every 2 seconds at minute values 1, 20 and 30 every hour. j1 = mgr.new_job(keep_printing, ['arg1', 'arg2'], every_seconds=2, minutes=[1, 20, 30])

#Remove the job. mgr.remove_job(j1)